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Eric Biggers ff7b11aa48 net: socket: set sock->sk to NULL after calling proto_ops::release()
Commit 9060cb719e ("net: crypto set sk to NULL when af_alg_release.")
fixed a use-after-free in sockfs_setattr() when an AF_ALG socket is
closed concurrently with fchownat().  However, it ignored that many
other proto_ops::release() methods don't set sock->sk to NULL and
therefore allow the same use-after-free:

    - base_sock_release
    - bnep_sock_release
    - cmtp_sock_release
    - data_sock_release
    - dn_release
    - hci_sock_release
    - hidp_sock_release
    - iucv_sock_release
    - l2cap_sock_release
    - llcp_sock_release
    - llc_ui_release
    - rawsock_release
    - rfcomm_sock_release
    - sco_sock_release
    - svc_release
    - vcc_release
    - x25_release

Rather than fixing all these and relying on every socket type to get
this right forever, just make __sock_release() set sock->sk to NULL
itself after calling proto_ops::release().

Reproducer that produces the KASAN splat when any of these socket types
are configured into the kernel:

    #include <pthread.h>
    #include <stdlib.h>
    #include <sys/socket.h>
    #include <unistd.h>

    pthread_t t;
    volatile int fd;

    void *close_thread(void *arg)
    {
        for (;;) {
            usleep(rand() % 100);
            close(fd);
        }
    }

    int main()
    {
        pthread_create(&t, NULL, close_thread, NULL);
        for (;;) {
            fd = socket(rand() % 50, rand() % 11, 0);
            fchownat(fd, "", 1000, 1000, 0x1000);
            close(fd);
        }
    }

Fixes: 86741ec254 ("net: core: Add a UID field to struct sock.")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25 10:40:57 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-02-24 09:28:26 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
arch Bug fixes. 2019-02-24 09:47:07 -08:00
block for-linus-20190215 2019-02-15 09:12:28 -08:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto net: crypto set sk to NULL when af_alg_release. 2019-02-18 12:01:24 -08:00
drivers tun: fix blocking read 2019-02-24 22:11:53 -08:00
firmware kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
fs Two bug fixes for old issues, both marked for stable. 2019-02-21 09:43:37 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-02-24 09:28:26 -08:00
init revert "initramfs: cleanup incomplete rootfs" 2019-02-21 09:00:59 -08:00
ipc ipc: IPCMNI limit check for semmni 2018-10-31 08:54:14 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-02-24 09:28:26 -08:00
lib Merge branch 'fixes-v5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-02-20 09:09:33 -08:00
mm mm, memory_hotplug: fix off-by-one in is_pageblock_removable 2019-02-21 09:01:01 -08:00
net net: socket: set sock->sk to NULL after calling proto_ops::release() 2019-02-25 10:40:57 -08:00
samples samples: mei: use /dev/mei0 instead of /dev/mei 2019-01-30 15:24:45 +01:00
scripts kallsyms: Handle too long symbols in kallsyms.c 2019-01-28 13:02:09 +09:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-02-24 09:28:26 -08:00
sound sound fixes for 5.0 2019-02-20 09:42:52 -08:00
tools selftests: fib_tests: sleep after changing carrier. again. 2019-02-23 18:34:20 -08:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt KVM/ARM fixes for 5.0: 2019-02-13 19:39:24 +01:00
.clang-format clang-format: Update .clang-format with the latest for_each macro list 2019-01-19 19:26:06 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap A few early MIPS fixes for 4.21: 2019-01-05 12:48:25 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS CREDITS/MAINTAINERS: Retire parisc-linux.org email domain 2019-02-21 20:16:10 +01:00
Kbuild kbuild: use assignment instead of define ... endef for filechk_* rules 2019-01-06 10:22:35 +09:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-02-24 09:28:26 -08:00
Makefile Linux 5.0-rc7 2019-02-17 18:46:40 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.