UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

riscv: kprobe: Fixup kernel panic when probing an illegal position 

The kernel would panic when probed for an illegal position. eg:

(CONFIG_RISCV_ISA_C=n)

echo 'p:hello kernel_clone+0x16 a0=%a0' >> kprobe_events
echo 1 > events/kprobes/hello/enable
cat trace

Kernel panic - not syncing: stack-protector: Kernel stack
is corrupted in: __do_sys_newfstatat+0xb8/0xb8
CPU: 0 PID: 111 Comm: sh Not tainted
6.2.0-rc1-00027-g2d398fe49a4d #490
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
[<ffffffff80007268>] dump_backtrace+0x38/0x48
[<ffffffff80c5e83c>] show_stack+0x50/0x68
[<ffffffff80c6da28>] dump_stack_lvl+0x60/0x84
[<ffffffff80c6da6c>] dump_stack+0x20/0x30
[<ffffffff80c5ecf4>] panic+0x160/0x374
[<ffffffff80c6db94>] generic_handle_arch_irq+0x0/0xa8
[<ffffffff802deeb0>] sys_newstat+0x0/0x30
[<ffffffff800158c0>] sys_clone+0x20/0x30
[<ffffffff800039e8>] ret_from_syscall+0x0/0x4
---[ end Kernel panic - not syncing: stack-protector:
Kernel stack is corrupted in: __do_sys_newfstatat+0xb8/0xb8 ]---

That is because the kprobe's ebreak instruction broke the kernel's
original code. The user should guarantee the correction of the probe
position, but it couldn't make the kernel panic.

This patch adds arch_check_kprobe in arch_prepare_kprobe to prevent an
illegal position (Such as the middle of an instruction).

Fixes: c22b0bcb1d ("riscv: Add kprobes supported")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20230201040604.3390509-1-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Guo Ren 2023-01-31 23:06:04 -05:00 committed by Palmer Dabbelt
parent 3c349eacc5
commit 87f48c7ccc
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
1 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
arch/riscv/kernel/probes/kprobes.c
View File

@ -48,6 +48,21 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
post_kprobe_handler(p, kcb, regs);
}
static bool __kprobes arch_check_kprobe(struct kprobe *p)
{
unsigned long tmp = (unsigned long)p->addr - p->offset;
unsigned long addr = (unsigned long)p->addr;
while (tmp <= addr) {
if (tmp == addr)
return true;
tmp += GET_INSN_LENGTH(*(u16 *)tmp);
}
return false;
}
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
unsigned long probe_addr = (unsigned long)p->addr;
@ -55,6 +70,9 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
if (probe_addr & 0x1)
return -EILSEQ;
if (!arch_check_kprobe(p))
return -EILSEQ;
/* copy instruction */
p->opcode = *p->addr;