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x86, x32, x86_64: do not skip syscall number -1

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Syscall number -1 might be a side effect of SECCOMP_RET_ERRNO filtering.

* syscall.c (syscall_fixup_on_sysenter) [I386 || X32 || X86_64]:
Do not skip syscalls that have number -1.
This commit is contained in:
Дмитрий Левин 2015-02-05 19:31:13 +00:00
parent c394832771
commit 8e398b6c40
1 changed files with 32 additions and 13 deletions
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45
syscall.c
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@ -1605,24 +1605,43 @@ syscall_fixup_on_sysenter(struct tcb *tcp)
{
/* A common case of "not a syscall entry" is post-execve SIGTRAP */
#if defined(I386)
if (i386_regs.eax != -ENOSYS) {
/*
* Syscall number -1 requires special treatment.
* On X86, it might be a side effect of SECCOMP_RET_ERRNO filtering
* that sets orig_eax to -1 in some versions of linux kernel.
*/
if (i386_regs.orig_eax != -1 &&
i386_regs.eax != -ENOSYS) {
if (debug_flag)
fprintf(stderr, "not a syscall entry (eax = %ld)\n", i386_regs.eax);
fprintf(stderr,
"not a syscall entry (eax = %ld, orig_eax = %ld)\n",
i386_regs.eax, i386_regs.orig_eax);
return 0;
}
#elif defined(X86_64) || defined(X32)
{
long rax;
if (x86_io.iov_len == sizeof(i386_regs)) {
/* Sign extend from 32 bits */
rax = (int32_t)i386_regs.eax;
} else {
/* Note: in X32 build, this truncates 64 to 32 bits */
rax = x86_64_regs.rax;
}
if (rax != -ENOSYS) {
/*
* Syscall number -1 requires special treatment.
* On X86_64/X32, it might be a side effect of SECCOMP_RET_ERRNO
* filtering that sets orig_rax to -1 in some versions of linux kernel.
*/
if (x86_io.iov_len == sizeof(i386_regs)) {
if ((int) i386_regs.orig_eax != -1 &&
(int) i386_regs.eax != -ENOSYS) {
if (debug_flag)
fprintf(stderr, "not a syscall entry (rax = %ld)\n", rax);
fprintf(stderr,
"not a syscall entry (eax = %d, orig_eax = %d)\n",
(int) i386_regs.eax,
(int) i386_regs.orig_eax);
return 0;
}
} else {
if ((long long) x86_64_regs.orig_rax != -1 &&
(long long) x86_64_regs.rax != -ENOSYS) {
if (debug_flag)
fprintf(stderr,
"not a syscall entry (rax = %lld, orig_rax = %lld)\n",
(long long) x86_64_regs.rax,
(long long) x86_64_regs.orig_rax);
return 0;
}
}