OpenCloudOS-Kernel/drivers/connector/cn_proc.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* cn_proc.c - process events connector
*
* Copyright (C) Matt Helsley, IBM Corp. 2005
* Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
* Original copyright notice follows:
* Copyright (C) 2005 BULL SA.
*/
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/connector.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/gfp.h>
#include <linux/ptrace.h>
#include <linux/atomic.h>
#include <linux/pid_namespace.h>
#include <linux/cn_proc.h>
/*
* Size of a cn_msg followed by a proc_event structure. Since the
* sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we
* add one 4-byte word to the size here, and then start the actual
* cn_msg structure 4 bytes into the stack buffer. The result is that
* the immediately following proc_event structure is aligned to 8 bytes.
*/
#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4)
/* See comment above; we test our assumption about sizeof struct cn_msg here. */
static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)
{
BUILD_BUG_ON(sizeof(struct cn_msg) != 20);
return (struct cn_msg *)(buffer + 4);
}
static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
/* proc_event_counts is used as the sequence number of the netlink message */
static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
static inline void send_msg(struct cn_msg *msg)
{
preempt_disable();
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;
((struct proc_event *)msg->data)->cpu = smp_processor_id();
/*
* Preemption remains disabled during send to ensure the messages are
* ordered according to their sequence numbers.
*
* If cn_netlink_send() fails, the data is not sent.
*/
cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
preempt_enable();
}
void proc_fork_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
struct task_struct *parent;
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_FORK;
rcu_read_lock();
parent = rcu_dereference(task->real_parent);
ev->event_data.fork.parent_pid = parent->pid;
ev->event_data.fork.parent_tgid = parent->tgid;
rcu_read_unlock();
ev->event_data.fork.child_pid = task->pid;
ev->event_data.fork.child_tgid = task->tgid;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
void proc_exec_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_EXEC;
ev->event_data.exec.process_pid = task->pid;
ev->event_data.exec.process_tgid = task->tgid;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
void proc_id_connector(struct task_struct *task, int which_id)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
const struct cred *cred;
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->what = which_id;
ev->event_data.id.process_pid = task->pid;
ev->event_data.id.process_tgid = task->tgid;
rcu_read_lock();
cred = __task_cred(task);
if (which_id == PROC_EVENT_UID) {
ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid);
ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid);
} else if (which_id == PROC_EVENT_GID) {
ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid);
ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid);
} else {
rcu_read_unlock();
return;
}
rcu_read_unlock();
ev->timestamp_ns = ktime_get_ns();
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
void proc_sid_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_SID;
ev->event_data.sid.process_pid = task->pid;
ev->event_data.sid.process_tgid = task->tgid;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_PTRACE;
ev->event_data.ptrace.process_pid = task->pid;
ev->event_data.ptrace.process_tgid = task->tgid;
if (ptrace_id == PTRACE_ATTACH) {
ev->event_data.ptrace.tracer_pid = current->pid;
ev->event_data.ptrace.tracer_tgid = current->tgid;
} else if (ptrace_id == PTRACE_DETACH) {
ev->event_data.ptrace.tracer_pid = 0;
ev->event_data.ptrace.tracer_tgid = 0;
} else
return;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
void proc_comm_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_COMM;
ev->event_data.comm.process_pid = task->pid;
ev->event_data.comm.process_tgid = task->tgid;
get_task_comm(ev->event_data.comm.comm, task);
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
void proc_coredump_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
connector: fix unsafe usage of ->real_parent proc_exit_connector() uses ->real_parent lockless. This is not safe that its parent can go away at any moment, so use RCU to protect it, and ensure that this task is not released. [ 747.624551] ================================================================== [ 747.632946] BUG: KASAN: use-after-free in proc_exit_connector+0x1f7/0x310 [ 747.640686] Read of size 4 at addr ffff88a0276988e0 by task sshd/2882 [ 747.648032] [ 747.649804] CPU: 11 PID: 2882 Comm: sshd Tainted: G E 4.19.26-rc2 #11 [ 747.658629] Hardware name: IBM x3550M4 -[7914OFV]-/00AM544, BIOS -[D7E142BUS-1.71]- 07/31/2014 [ 747.668419] Call Trace: [ 747.671269] dump_stack+0xf0/0x19b [ 747.675186] ? show_regs_print_info+0x5/0x5 [ 747.679988] ? kmsg_dump_rewind_nolock+0x59/0x59 [ 747.685302] print_address_description+0x6a/0x270 [ 747.691162] kasan_report+0x258/0x380 [ 747.695835] ? proc_exit_connector+0x1f7/0x310 [ 747.701402] proc_exit_connector+0x1f7/0x310 [ 747.706767] ? proc_coredump_connector+0x2d0/0x2d0 [ 747.712715] ? _raw_write_unlock_irq+0x29/0x50 [ 747.718270] ? _raw_write_unlock_irq+0x29/0x50 [ 747.723820] ? ___preempt_schedule+0x16/0x18 [ 747.729193] ? ___preempt_schedule+0x16/0x18 [ 747.734574] do_exit+0xa11/0x14f0 [ 747.738880] ? mm_update_next_owner+0x590/0x590 [ 747.744525] ? debug_show_all_locks+0x3c0/0x3c0 [ 747.761448] ? ktime_get_coarse_real_ts64+0xeb/0x1c0 [ 747.767589] ? lockdep_hardirqs_on+0x1a6/0x290 [ 747.773154] ? check_chain_key+0x139/0x1f0 [ 747.778345] ? check_flags.part.35+0x240/0x240 [ 747.783908] ? __lock_acquire+0x2300/0x2300 [ 747.789171] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.795316] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.801457] ? do_raw_spin_unlock+0x10f/0x1e0 [ 747.806914] ? do_raw_spin_trylock+0x120/0x120 [ 747.812481] ? preempt_count_sub+0x14/0xc0 [ 747.817645] ? _raw_spin_unlock+0x2e/0x50 [ 747.822708] ? __handle_mm_fault+0x12db/0x1fa0 [ 747.828367] ? __pmd_alloc+0x2d0/0x2d0 [ 747.833143] ? check_noncircular+0x50/0x50 [ 747.838309] ? match_held_lock+0x7f/0x340 [ 747.843380] ? check_noncircular+0x50/0x50 [ 747.848561] ? handle_mm_fault+0x21a/0x5f0 [ 747.853730] ? check_flags.part.35+0x240/0x240 [ 747.859290] ? check_chain_key+0x139/0x1f0 [ 747.864474] ? __do_page_fault+0x40f/0x760 [ 747.869655] ? __audit_syscall_entry+0x4b/0x1f0 [ 747.875319] ? syscall_trace_enter+0x1d5/0x7b0 [ 747.880877] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.887895] ? trace_raw_output_sys_exit+0x80/0x80 [ 747.893860] ? up_read+0x3b/0x90 [ 747.898142] ? stop_critical_timings+0x260/0x260 [ 747.903909] do_group_exit+0xe0/0x1c0 [ 747.908591] ? __x64_sys_exit+0x30/0x30 [ 747.913460] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.920485] ? tracer_hardirqs_on+0x270/0x270 [ 747.925956] __x64_sys_exit_group+0x28/0x30 [ 747.931214] do_syscall_64+0x117/0x400 [ 747.935988] ? syscall_return_slowpath+0x2f0/0x2f0 [ 747.941931] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.947788] ? trace_hardirqs_on_caller+0x1d0/0x1d0 [ 747.953838] ? lockdep_sys_exit+0x16/0x8e [ 747.958915] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.964784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 747.971021] RIP: 0033:0x7f572f154c68 [ 747.975606] Code: Bad RIP value. [ 747.979791] RSP: 002b:00007ffed2dfaa58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 747.989324] RAX: ffffffffffffffda RBX: 00007f572f431840 RCX: 00007f572f154c68 [ 747.997910] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 748.006495] RBP: 0000000000000001 R08: 00000000000000e7 R09: fffffffffffffee0 [ 748.015079] R10: 00007f572f4387e8 R11: 0000000000000246 R12: 00007f572f431840 [ 748.023664] R13: 000055a7f90f2c50 R14: 000055a7f96e2310 R15: 000055a7f96e2310 [ 748.032287] [ 748.034509] Allocated by task 2300: [ 748.038982] kasan_kmalloc+0xa0/0xd0 [ 748.043562] kmem_cache_alloc_node+0xf5/0x2e0 [ 748.049018] copy_process+0x1781/0x4790 [ 748.053884] _do_fork+0x166/0x9a0 [ 748.058163] do_syscall_64+0x117/0x400 [ 748.062943] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.069180] [ 748.071405] Freed by task 15395: [ 748.075591] __kasan_slab_free+0x130/0x180 [ 748.080752] kmem_cache_free+0xc2/0x310 [ 748.085619] free_task+0xea/0x130 [ 748.089901] __put_task_struct+0x177/0x230 [ 748.095063] finish_task_switch+0x51b/0x5d0 [ 748.100315] __schedule+0x506/0xfa0 [ 748.104791] schedule+0xca/0x260 [ 748.108978] futex_wait_queue_me+0x27e/0x420 [ 748.114333] futex_wait+0x251/0x550 [ 748.118814] do_futex+0x75b/0xf80 [ 748.123097] __x64_sys_futex+0x231/0x2a0 [ 748.128065] do_syscall_64+0x117/0x400 [ 748.132835] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.139066] [ 748.141289] The buggy address belongs to the object at ffff88a027698000 [ 748.141289] which belongs to the cache task_struct of size 12160 [ 748.156589] The buggy address is located 2272 bytes inside of [ 748.156589] 12160-byte region [ffff88a027698000, ffff88a02769af80) [ 748.171114] The buggy address belongs to the page: [ 748.177055] page:ffffea00809da600 count:1 mapcount:0 mapping:ffff888107d01e00 index:0x0 compound_mapcount: 0 [ 748.189136] flags: 0x57ffffc0008100(slab|head) [ 748.194688] raw: 0057ffffc0008100 ffffea00809a3200 0000000300000003 ffff888107d01e00 [ 748.204424] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 [ 748.214146] page dumped because: kasan: bad access detected [ 748.220976] [ 748.223197] Memory state around the buggy address: [ 748.229128] ffff88a027698780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.238271] ffff88a027698800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.247414] >ffff88a027698880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.256564] ^ [ 748.264267] ffff88a027698900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.273493] ffff88a027698980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.282630] ================================================================== Fixes: b086ff87251b4a4 ("connector: add parent pid and tgid to coredump and exit events") Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-06 14:46:27 +08:00
struct task_struct *parent;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_COREDUMP;
ev->event_data.coredump.process_pid = task->pid;
ev->event_data.coredump.process_tgid = task->tgid;
connector: fix unsafe usage of ->real_parent proc_exit_connector() uses ->real_parent lockless. This is not safe that its parent can go away at any moment, so use RCU to protect it, and ensure that this task is not released. [ 747.624551] ================================================================== [ 747.632946] BUG: KASAN: use-after-free in proc_exit_connector+0x1f7/0x310 [ 747.640686] Read of size 4 at addr ffff88a0276988e0 by task sshd/2882 [ 747.648032] [ 747.649804] CPU: 11 PID: 2882 Comm: sshd Tainted: G E 4.19.26-rc2 #11 [ 747.658629] Hardware name: IBM x3550M4 -[7914OFV]-/00AM544, BIOS -[D7E142BUS-1.71]- 07/31/2014 [ 747.668419] Call Trace: [ 747.671269] dump_stack+0xf0/0x19b [ 747.675186] ? show_regs_print_info+0x5/0x5 [ 747.679988] ? kmsg_dump_rewind_nolock+0x59/0x59 [ 747.685302] print_address_description+0x6a/0x270 [ 747.691162] kasan_report+0x258/0x380 [ 747.695835] ? proc_exit_connector+0x1f7/0x310 [ 747.701402] proc_exit_connector+0x1f7/0x310 [ 747.706767] ? proc_coredump_connector+0x2d0/0x2d0 [ 747.712715] ? _raw_write_unlock_irq+0x29/0x50 [ 747.718270] ? _raw_write_unlock_irq+0x29/0x50 [ 747.723820] ? ___preempt_schedule+0x16/0x18 [ 747.729193] ? ___preempt_schedule+0x16/0x18 [ 747.734574] do_exit+0xa11/0x14f0 [ 747.738880] ? mm_update_next_owner+0x590/0x590 [ 747.744525] ? debug_show_all_locks+0x3c0/0x3c0 [ 747.761448] ? ktime_get_coarse_real_ts64+0xeb/0x1c0 [ 747.767589] ? lockdep_hardirqs_on+0x1a6/0x290 [ 747.773154] ? check_chain_key+0x139/0x1f0 [ 747.778345] ? check_flags.part.35+0x240/0x240 [ 747.783908] ? __lock_acquire+0x2300/0x2300 [ 747.789171] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.795316] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.801457] ? do_raw_spin_unlock+0x10f/0x1e0 [ 747.806914] ? do_raw_spin_trylock+0x120/0x120 [ 747.812481] ? preempt_count_sub+0x14/0xc0 [ 747.817645] ? _raw_spin_unlock+0x2e/0x50 [ 747.822708] ? __handle_mm_fault+0x12db/0x1fa0 [ 747.828367] ? __pmd_alloc+0x2d0/0x2d0 [ 747.833143] ? check_noncircular+0x50/0x50 [ 747.838309] ? match_held_lock+0x7f/0x340 [ 747.843380] ? check_noncircular+0x50/0x50 [ 747.848561] ? handle_mm_fault+0x21a/0x5f0 [ 747.853730] ? check_flags.part.35+0x240/0x240 [ 747.859290] ? check_chain_key+0x139/0x1f0 [ 747.864474] ? __do_page_fault+0x40f/0x760 [ 747.869655] ? __audit_syscall_entry+0x4b/0x1f0 [ 747.875319] ? syscall_trace_enter+0x1d5/0x7b0 [ 747.880877] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.887895] ? trace_raw_output_sys_exit+0x80/0x80 [ 747.893860] ? up_read+0x3b/0x90 [ 747.898142] ? stop_critical_timings+0x260/0x260 [ 747.903909] do_group_exit+0xe0/0x1c0 [ 747.908591] ? __x64_sys_exit+0x30/0x30 [ 747.913460] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.920485] ? tracer_hardirqs_on+0x270/0x270 [ 747.925956] __x64_sys_exit_group+0x28/0x30 [ 747.931214] do_syscall_64+0x117/0x400 [ 747.935988] ? syscall_return_slowpath+0x2f0/0x2f0 [ 747.941931] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.947788] ? trace_hardirqs_on_caller+0x1d0/0x1d0 [ 747.953838] ? lockdep_sys_exit+0x16/0x8e [ 747.958915] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.964784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 747.971021] RIP: 0033:0x7f572f154c68 [ 747.975606] Code: Bad RIP value. [ 747.979791] RSP: 002b:00007ffed2dfaa58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 747.989324] RAX: ffffffffffffffda RBX: 00007f572f431840 RCX: 00007f572f154c68 [ 747.997910] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 748.006495] RBP: 0000000000000001 R08: 00000000000000e7 R09: fffffffffffffee0 [ 748.015079] R10: 00007f572f4387e8 R11: 0000000000000246 R12: 00007f572f431840 [ 748.023664] R13: 000055a7f90f2c50 R14: 000055a7f96e2310 R15: 000055a7f96e2310 [ 748.032287] [ 748.034509] Allocated by task 2300: [ 748.038982] kasan_kmalloc+0xa0/0xd0 [ 748.043562] kmem_cache_alloc_node+0xf5/0x2e0 [ 748.049018] copy_process+0x1781/0x4790 [ 748.053884] _do_fork+0x166/0x9a0 [ 748.058163] do_syscall_64+0x117/0x400 [ 748.062943] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.069180] [ 748.071405] Freed by task 15395: [ 748.075591] __kasan_slab_free+0x130/0x180 [ 748.080752] kmem_cache_free+0xc2/0x310 [ 748.085619] free_task+0xea/0x130 [ 748.089901] __put_task_struct+0x177/0x230 [ 748.095063] finish_task_switch+0x51b/0x5d0 [ 748.100315] __schedule+0x506/0xfa0 [ 748.104791] schedule+0xca/0x260 [ 748.108978] futex_wait_queue_me+0x27e/0x420 [ 748.114333] futex_wait+0x251/0x550 [ 748.118814] do_futex+0x75b/0xf80 [ 748.123097] __x64_sys_futex+0x231/0x2a0 [ 748.128065] do_syscall_64+0x117/0x400 [ 748.132835] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.139066] [ 748.141289] The buggy address belongs to the object at ffff88a027698000 [ 748.141289] which belongs to the cache task_struct of size 12160 [ 748.156589] The buggy address is located 2272 bytes inside of [ 748.156589] 12160-byte region [ffff88a027698000, ffff88a02769af80) [ 748.171114] The buggy address belongs to the page: [ 748.177055] page:ffffea00809da600 count:1 mapcount:0 mapping:ffff888107d01e00 index:0x0 compound_mapcount: 0 [ 748.189136] flags: 0x57ffffc0008100(slab|head) [ 748.194688] raw: 0057ffffc0008100 ffffea00809a3200 0000000300000003 ffff888107d01e00 [ 748.204424] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 [ 748.214146] page dumped because: kasan: bad access detected [ 748.220976] [ 748.223197] Memory state around the buggy address: [ 748.229128] ffff88a027698780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.238271] ffff88a027698800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.247414] >ffff88a027698880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.256564] ^ [ 748.264267] ffff88a027698900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.273493] ffff88a027698980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.282630] ================================================================== Fixes: b086ff87251b4a4 ("connector: add parent pid and tgid to coredump and exit events") Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-06 14:46:27 +08:00
rcu_read_lock();
if (pid_alive(task)) {
parent = rcu_dereference(task->real_parent);
ev->event_data.coredump.parent_pid = parent->pid;
ev->event_data.coredump.parent_tgid = parent->tgid;
}
rcu_read_unlock();
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
void proc_exit_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
connector: fix unsafe usage of ->real_parent proc_exit_connector() uses ->real_parent lockless. This is not safe that its parent can go away at any moment, so use RCU to protect it, and ensure that this task is not released. [ 747.624551] ================================================================== [ 747.632946] BUG: KASAN: use-after-free in proc_exit_connector+0x1f7/0x310 [ 747.640686] Read of size 4 at addr ffff88a0276988e0 by task sshd/2882 [ 747.648032] [ 747.649804] CPU: 11 PID: 2882 Comm: sshd Tainted: G E 4.19.26-rc2 #11 [ 747.658629] Hardware name: IBM x3550M4 -[7914OFV]-/00AM544, BIOS -[D7E142BUS-1.71]- 07/31/2014 [ 747.668419] Call Trace: [ 747.671269] dump_stack+0xf0/0x19b [ 747.675186] ? show_regs_print_info+0x5/0x5 [ 747.679988] ? kmsg_dump_rewind_nolock+0x59/0x59 [ 747.685302] print_address_description+0x6a/0x270 [ 747.691162] kasan_report+0x258/0x380 [ 747.695835] ? proc_exit_connector+0x1f7/0x310 [ 747.701402] proc_exit_connector+0x1f7/0x310 [ 747.706767] ? proc_coredump_connector+0x2d0/0x2d0 [ 747.712715] ? _raw_write_unlock_irq+0x29/0x50 [ 747.718270] ? _raw_write_unlock_irq+0x29/0x50 [ 747.723820] ? ___preempt_schedule+0x16/0x18 [ 747.729193] ? ___preempt_schedule+0x16/0x18 [ 747.734574] do_exit+0xa11/0x14f0 [ 747.738880] ? mm_update_next_owner+0x590/0x590 [ 747.744525] ? debug_show_all_locks+0x3c0/0x3c0 [ 747.761448] ? ktime_get_coarse_real_ts64+0xeb/0x1c0 [ 747.767589] ? lockdep_hardirqs_on+0x1a6/0x290 [ 747.773154] ? check_chain_key+0x139/0x1f0 [ 747.778345] ? check_flags.part.35+0x240/0x240 [ 747.783908] ? __lock_acquire+0x2300/0x2300 [ 747.789171] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.795316] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.801457] ? do_raw_spin_unlock+0x10f/0x1e0 [ 747.806914] ? do_raw_spin_trylock+0x120/0x120 [ 747.812481] ? preempt_count_sub+0x14/0xc0 [ 747.817645] ? _raw_spin_unlock+0x2e/0x50 [ 747.822708] ? __handle_mm_fault+0x12db/0x1fa0 [ 747.828367] ? __pmd_alloc+0x2d0/0x2d0 [ 747.833143] ? check_noncircular+0x50/0x50 [ 747.838309] ? match_held_lock+0x7f/0x340 [ 747.843380] ? check_noncircular+0x50/0x50 [ 747.848561] ? handle_mm_fault+0x21a/0x5f0 [ 747.853730] ? check_flags.part.35+0x240/0x240 [ 747.859290] ? check_chain_key+0x139/0x1f0 [ 747.864474] ? __do_page_fault+0x40f/0x760 [ 747.869655] ? __audit_syscall_entry+0x4b/0x1f0 [ 747.875319] ? syscall_trace_enter+0x1d5/0x7b0 [ 747.880877] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.887895] ? trace_raw_output_sys_exit+0x80/0x80 [ 747.893860] ? up_read+0x3b/0x90 [ 747.898142] ? stop_critical_timings+0x260/0x260 [ 747.903909] do_group_exit+0xe0/0x1c0 [ 747.908591] ? __x64_sys_exit+0x30/0x30 [ 747.913460] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.920485] ? tracer_hardirqs_on+0x270/0x270 [ 747.925956] __x64_sys_exit_group+0x28/0x30 [ 747.931214] do_syscall_64+0x117/0x400 [ 747.935988] ? syscall_return_slowpath+0x2f0/0x2f0 [ 747.941931] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.947788] ? trace_hardirqs_on_caller+0x1d0/0x1d0 [ 747.953838] ? lockdep_sys_exit+0x16/0x8e [ 747.958915] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.964784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 747.971021] RIP: 0033:0x7f572f154c68 [ 747.975606] Code: Bad RIP value. [ 747.979791] RSP: 002b:00007ffed2dfaa58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 747.989324] RAX: ffffffffffffffda RBX: 00007f572f431840 RCX: 00007f572f154c68 [ 747.997910] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 748.006495] RBP: 0000000000000001 R08: 00000000000000e7 R09: fffffffffffffee0 [ 748.015079] R10: 00007f572f4387e8 R11: 0000000000000246 R12: 00007f572f431840 [ 748.023664] R13: 000055a7f90f2c50 R14: 000055a7f96e2310 R15: 000055a7f96e2310 [ 748.032287] [ 748.034509] Allocated by task 2300: [ 748.038982] kasan_kmalloc+0xa0/0xd0 [ 748.043562] kmem_cache_alloc_node+0xf5/0x2e0 [ 748.049018] copy_process+0x1781/0x4790 [ 748.053884] _do_fork+0x166/0x9a0 [ 748.058163] do_syscall_64+0x117/0x400 [ 748.062943] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.069180] [ 748.071405] Freed by task 15395: [ 748.075591] __kasan_slab_free+0x130/0x180 [ 748.080752] kmem_cache_free+0xc2/0x310 [ 748.085619] free_task+0xea/0x130 [ 748.089901] __put_task_struct+0x177/0x230 [ 748.095063] finish_task_switch+0x51b/0x5d0 [ 748.100315] __schedule+0x506/0xfa0 [ 748.104791] schedule+0xca/0x260 [ 748.108978] futex_wait_queue_me+0x27e/0x420 [ 748.114333] futex_wait+0x251/0x550 [ 748.118814] do_futex+0x75b/0xf80 [ 748.123097] __x64_sys_futex+0x231/0x2a0 [ 748.128065] do_syscall_64+0x117/0x400 [ 748.132835] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.139066] [ 748.141289] The buggy address belongs to the object at ffff88a027698000 [ 748.141289] which belongs to the cache task_struct of size 12160 [ 748.156589] The buggy address is located 2272 bytes inside of [ 748.156589] 12160-byte region [ffff88a027698000, ffff88a02769af80) [ 748.171114] The buggy address belongs to the page: [ 748.177055] page:ffffea00809da600 count:1 mapcount:0 mapping:ffff888107d01e00 index:0x0 compound_mapcount: 0 [ 748.189136] flags: 0x57ffffc0008100(slab|head) [ 748.194688] raw: 0057ffffc0008100 ffffea00809a3200 0000000300000003 ffff888107d01e00 [ 748.204424] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 [ 748.214146] page dumped because: kasan: bad access detected [ 748.220976] [ 748.223197] Memory state around the buggy address: [ 748.229128] ffff88a027698780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.238271] ffff88a027698800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.247414] >ffff88a027698880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.256564] ^ [ 748.264267] ffff88a027698900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.273493] ffff88a027698980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.282630] ================================================================== Fixes: b086ff87251b4a4 ("connector: add parent pid and tgid to coredump and exit events") Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-06 14:46:27 +08:00
struct task_struct *parent;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_EXIT;
ev->event_data.exit.process_pid = task->pid;
ev->event_data.exit.process_tgid = task->tgid;
ev->event_data.exit.exit_code = task->exit_code;
ev->event_data.exit.exit_signal = task->exit_signal;
connector: fix unsafe usage of ->real_parent proc_exit_connector() uses ->real_parent lockless. This is not safe that its parent can go away at any moment, so use RCU to protect it, and ensure that this task is not released. [ 747.624551] ================================================================== [ 747.632946] BUG: KASAN: use-after-free in proc_exit_connector+0x1f7/0x310 [ 747.640686] Read of size 4 at addr ffff88a0276988e0 by task sshd/2882 [ 747.648032] [ 747.649804] CPU: 11 PID: 2882 Comm: sshd Tainted: G E 4.19.26-rc2 #11 [ 747.658629] Hardware name: IBM x3550M4 -[7914OFV]-/00AM544, BIOS -[D7E142BUS-1.71]- 07/31/2014 [ 747.668419] Call Trace: [ 747.671269] dump_stack+0xf0/0x19b [ 747.675186] ? show_regs_print_info+0x5/0x5 [ 747.679988] ? kmsg_dump_rewind_nolock+0x59/0x59 [ 747.685302] print_address_description+0x6a/0x270 [ 747.691162] kasan_report+0x258/0x380 [ 747.695835] ? proc_exit_connector+0x1f7/0x310 [ 747.701402] proc_exit_connector+0x1f7/0x310 [ 747.706767] ? proc_coredump_connector+0x2d0/0x2d0 [ 747.712715] ? _raw_write_unlock_irq+0x29/0x50 [ 747.718270] ? _raw_write_unlock_irq+0x29/0x50 [ 747.723820] ? ___preempt_schedule+0x16/0x18 [ 747.729193] ? ___preempt_schedule+0x16/0x18 [ 747.734574] do_exit+0xa11/0x14f0 [ 747.738880] ? mm_update_next_owner+0x590/0x590 [ 747.744525] ? debug_show_all_locks+0x3c0/0x3c0 [ 747.761448] ? ktime_get_coarse_real_ts64+0xeb/0x1c0 [ 747.767589] ? lockdep_hardirqs_on+0x1a6/0x290 [ 747.773154] ? check_chain_key+0x139/0x1f0 [ 747.778345] ? check_flags.part.35+0x240/0x240 [ 747.783908] ? __lock_acquire+0x2300/0x2300 [ 747.789171] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.795316] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.801457] ? do_raw_spin_unlock+0x10f/0x1e0 [ 747.806914] ? do_raw_spin_trylock+0x120/0x120 [ 747.812481] ? preempt_count_sub+0x14/0xc0 [ 747.817645] ? _raw_spin_unlock+0x2e/0x50 [ 747.822708] ? __handle_mm_fault+0x12db/0x1fa0 [ 747.828367] ? __pmd_alloc+0x2d0/0x2d0 [ 747.833143] ? check_noncircular+0x50/0x50 [ 747.838309] ? match_held_lock+0x7f/0x340 [ 747.843380] ? check_noncircular+0x50/0x50 [ 747.848561] ? handle_mm_fault+0x21a/0x5f0 [ 747.853730] ? check_flags.part.35+0x240/0x240 [ 747.859290] ? check_chain_key+0x139/0x1f0 [ 747.864474] ? __do_page_fault+0x40f/0x760 [ 747.869655] ? __audit_syscall_entry+0x4b/0x1f0 [ 747.875319] ? syscall_trace_enter+0x1d5/0x7b0 [ 747.880877] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.887895] ? trace_raw_output_sys_exit+0x80/0x80 [ 747.893860] ? up_read+0x3b/0x90 [ 747.898142] ? stop_critical_timings+0x260/0x260 [ 747.903909] do_group_exit+0xe0/0x1c0 [ 747.908591] ? __x64_sys_exit+0x30/0x30 [ 747.913460] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.920485] ? tracer_hardirqs_on+0x270/0x270 [ 747.925956] __x64_sys_exit_group+0x28/0x30 [ 747.931214] do_syscall_64+0x117/0x400 [ 747.935988] ? syscall_return_slowpath+0x2f0/0x2f0 [ 747.941931] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.947788] ? trace_hardirqs_on_caller+0x1d0/0x1d0 [ 747.953838] ? lockdep_sys_exit+0x16/0x8e [ 747.958915] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.964784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 747.971021] RIP: 0033:0x7f572f154c68 [ 747.975606] Code: Bad RIP value. [ 747.979791] RSP: 002b:00007ffed2dfaa58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 747.989324] RAX: ffffffffffffffda RBX: 00007f572f431840 RCX: 00007f572f154c68 [ 747.997910] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 748.006495] RBP: 0000000000000001 R08: 00000000000000e7 R09: fffffffffffffee0 [ 748.015079] R10: 00007f572f4387e8 R11: 0000000000000246 R12: 00007f572f431840 [ 748.023664] R13: 000055a7f90f2c50 R14: 000055a7f96e2310 R15: 000055a7f96e2310 [ 748.032287] [ 748.034509] Allocated by task 2300: [ 748.038982] kasan_kmalloc+0xa0/0xd0 [ 748.043562] kmem_cache_alloc_node+0xf5/0x2e0 [ 748.049018] copy_process+0x1781/0x4790 [ 748.053884] _do_fork+0x166/0x9a0 [ 748.058163] do_syscall_64+0x117/0x400 [ 748.062943] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.069180] [ 748.071405] Freed by task 15395: [ 748.075591] __kasan_slab_free+0x130/0x180 [ 748.080752] kmem_cache_free+0xc2/0x310 [ 748.085619] free_task+0xea/0x130 [ 748.089901] __put_task_struct+0x177/0x230 [ 748.095063] finish_task_switch+0x51b/0x5d0 [ 748.100315] __schedule+0x506/0xfa0 [ 748.104791] schedule+0xca/0x260 [ 748.108978] futex_wait_queue_me+0x27e/0x420 [ 748.114333] futex_wait+0x251/0x550 [ 748.118814] do_futex+0x75b/0xf80 [ 748.123097] __x64_sys_futex+0x231/0x2a0 [ 748.128065] do_syscall_64+0x117/0x400 [ 748.132835] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.139066] [ 748.141289] The buggy address belongs to the object at ffff88a027698000 [ 748.141289] which belongs to the cache task_struct of size 12160 [ 748.156589] The buggy address is located 2272 bytes inside of [ 748.156589] 12160-byte region [ffff88a027698000, ffff88a02769af80) [ 748.171114] The buggy address belongs to the page: [ 748.177055] page:ffffea00809da600 count:1 mapcount:0 mapping:ffff888107d01e00 index:0x0 compound_mapcount: 0 [ 748.189136] flags: 0x57ffffc0008100(slab|head) [ 748.194688] raw: 0057ffffc0008100 ffffea00809a3200 0000000300000003 ffff888107d01e00 [ 748.204424] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 [ 748.214146] page dumped because: kasan: bad access detected [ 748.220976] [ 748.223197] Memory state around the buggy address: [ 748.229128] ffff88a027698780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.238271] ffff88a027698800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.247414] >ffff88a027698880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.256564] ^ [ 748.264267] ffff88a027698900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.273493] ffff88a027698980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.282630] ================================================================== Fixes: b086ff87251b4a4 ("connector: add parent pid and tgid to coredump and exit events") Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-06 14:46:27 +08:00
rcu_read_lock();
if (pid_alive(task)) {
parent = rcu_dereference(task->real_parent);
ev->event_data.exit.parent_pid = parent->pid;
ev->event_data.exit.parent_tgid = parent->tgid;
}
rcu_read_unlock();
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
/*
* Send an acknowledgement message to userspace
*
* Use 0 for success, EFOO otherwise.
* Note: this is the negative of conventional kernel error
* values because it's not being returned via syscall return
* mechanisms.
*/
static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
msg->seq = rcvd_seq;
ev->timestamp_ns = ktime_get_ns();
ev->cpu = -1;
ev->what = PROC_EVENT_NONE;
ev->event_data.ack.err = err;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = rcvd_ack + 1;
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
connector: fix out-of-order cn_proc netlink message delivery The proc connector messages include a sequence number, allowing userspace programs to detect lost messages. However, performing this detection is currently more difficult than necessary, since netlink messages can be delivered to the application out-of-order. To fix this, leave pre-emption disabled during cn_netlink_send(), and use GFP_NOWAIT. The following was written as a test case. Building the kernel w/ make -j32 proved a reliable way to generate out-of-order cn_proc messages. int main(int argc, char *argv[]) { static uint32_t last_seq[CPU_SETSIZE], seq; int cpu, fd; struct sockaddr_nl sa; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; struct proc_event cn_proc; }; } rmsg; struct __attribute__((aligned(NLMSG_ALIGNTO))) { struct nlmsghdr nl_hdr; struct __attribute__((__packed__)) { struct cn_msg cn_msg; enum proc_cn_mcast_op cn_mcast; }; } smsg; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); if (fd < 0) { perror("socket"); } sa.nl_family = AF_NETLINK; sa.nl_groups = CN_IDX_PROC; sa.nl_pid = getpid(); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); } memset(&smsg, 0, sizeof(smsg)); smsg.nl_hdr.nlmsg_len = sizeof(smsg); smsg.nl_hdr.nlmsg_pid = getpid(); smsg.nl_hdr.nlmsg_type = NLMSG_DONE; smsg.cn_msg.id.idx = CN_IDX_PROC; smsg.cn_msg.id.val = CN_VAL_PROC; smsg.cn_msg.len = sizeof(enum proc_cn_mcast_op); smsg.cn_mcast = PROC_CN_MCAST_LISTEN; if (send(fd, &smsg, sizeof(smsg), 0) != sizeof(smsg)) { perror("send"); } while (recv(fd, &rmsg, sizeof(rmsg), 0) == sizeof(rmsg)) { cpu = rmsg.cn_proc.cpu; if (cpu < 0) { continue; } seq = rmsg.cn_msg.seq; if ((last_seq[cpu] != 0) && (seq != last_seq[cpu] + 1)) { printf("out-of-order seq=%d on cpu=%d\n", seq, cpu); } last_seq[cpu] = seq; } /* NOTREACHED */ perror("recv"); return -1; } Signed-off-by: Aaron Campbell <aaron@monkey.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-24 21:05:32 +08:00
send_msg(msg);
}
/**
* cn_proc_mcast_ctl
* @data: message sent from userspace via the connector
*/
static void cn_proc_mcast_ctl(struct cn_msg *msg,
struct netlink_skb_parms *nsp)
{
enum proc_cn_mcast_op *mc_op = NULL;
int err = 0;
if (msg->len != sizeof(*mc_op))
return;
/*
* Events are reported with respect to the initial pid
* and user namespaces so ignore requestors from
* other namespaces.
*/
if ((current_user_ns() != &init_user_ns) ||
(task_active_pid_ns(current) != &init_pid_ns))
return;
/* Can only change if privileged. */
if (!__netlink_ns_capable(nsp, &init_user_ns, CAP_NET_ADMIN)) {
err = EPERM;
goto out;
}
mc_op = (enum proc_cn_mcast_op *)msg->data;
switch (*mc_op) {
case PROC_CN_MCAST_LISTEN:
atomic_inc(&proc_event_num_listeners);
break;
case PROC_CN_MCAST_IGNORE:
atomic_dec(&proc_event_num_listeners);
break;
default:
err = EINVAL;
break;
}
out:
cn_proc_ack(err, msg->seq, msg->ack);
}
/*
* cn_proc_init - initialization entry point
*
* Adds the connector callback to the connector driver.
*/
static int __init cn_proc_init(void)
{
int err = cn_add_callback(&cn_proc_event_id,
"cn_proc",
&cn_proc_mcast_ctl);
if (err) {
pr_warn("cn_proc failed to register\n");
return err;
}
return 0;
}
device_initcall(cn_proc_init);