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| author | Will Drewry <wad@chromium.org> | 2012-04-12 16:48:03 -0500 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2012-04-14 11:13:21 +1000 |
| commit | c6cfbeb4029610c8c330c312dcf4d514cc067554 (patch) | |
| tree | d61f1431884e042dc47ceb020fbcfada0c66bb3b | |
| parent | fb0fadf9b213f55ca9368f3edafe51101d5d2deb (diff) | |
| download | linux-c6cfbeb4029610c8c330c312dcf4d514cc067554.tar.gz linux-c6cfbeb4029610c8c330c312dcf4d514cc067554.tar.bz2 linux-c6cfbeb4029610c8c330c312dcf4d514cc067554.zip | |
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/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 7 |
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; } |