aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorWill Drewry <wad@chromium.org>2012-04-12 16:48:03 -0500
committerJames Morris <james.l.morris@oracle.com>2012-04-14 11:13:21 +1000
commitc6cfbeb4029610c8c330c312dcf4d514cc067554 (patch)
treed61f1431884e042dc47ceb020fbcfada0c66bb3b
parentfb0fadf9b213f55ca9368f3edafe51101d5d2deb (diff)
downloadlinux-linaro-stable-c6cfbeb4029610c8c330c312dcf4d514cc067554.tar.gz
x86: Enable HAVE_ARCH_SECCOMP_FILTER
Enable support for seccomp filter on x86: - syscall_get_arch() - syscall_get_arguments() - syscall_rollback() - syscall_set_return_value() - SIGSYS siginfo_t support - secure_computing is called from a ptrace_event()-safe context - secure_computing return value is checked (see below). SECCOMP_RET_TRACE and SECCOMP_RET_TRAP may result in seccomp needing to skip a system call without killing the process. This is done by returning a non-zero (-1) value from secure_computing. This change makes x86 respect that return value. To ensure that minimal kernel code is exposed, a non-zero return value results in an immediate return to user space (with an invalid syscall number). Signed-off-by: Will Drewry <wad@chromium.org> Reviewed-by: H. Peter Anvin <hpa@zytor.com> Acked-by: Eric Paris <eparis@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> v18: rebase and tweaked change description, acked-by v17: added reviewed by and rebased v..: all rebases since original introduction. Signed-off-by: James Morris <james.l.morris@oracle.com>
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/kernel/ptrace.c7
2 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d14cc6b79ad..3a41c4424a0a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -82,6 +82,7 @@ config X86
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_IOMAP
select DCACHE_WORD_ACCESS if !DEBUG_PAGEALLOC
+ select HAVE_ARCH_SECCOMP_FILTER
config INSTRUCTION_DECODER
def_bool (KPROBES || PERF_EVENTS)
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 685845cf16e0..13b1990c7c58 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -1480,7 +1480,11 @@ long syscall_trace_enter(struct pt_regs *regs)
regs->flags |= X86_EFLAGS_TF;
/* do the secure computing check first */
- secure_computing(regs->orig_ax);
+ if (secure_computing(regs->orig_ax)) {
+ /* seccomp failures shouldn't expose any additional code. */
+ ret = -1L;
+ goto out;
+ }
if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
ret = -1L;
@@ -1505,6 +1509,7 @@ long syscall_trace_enter(struct pt_regs *regs)
regs->dx, regs->r10);
#endif
+out:
return ret ?: regs->orig_ax;
}