diff options
| author | Will Drewry <wad@chromium.org> | 2012-02-09 11:28:23 -0600 |
|---|---|---|
| committer | John Rigby <john.rigby@linaro.org> | 2012-06-25 15:04:04 -0600 |
| commit | 1830178fdb0092f9863f279b6d00f59ae2135df1 (patch) | |
| tree | b9ff91c8f9a178189ed1c6133a05bccc8c514143 | |
| parent | f30e6e5a95389f12f3abcf5080dfe6c571804330 (diff) | |
UBUNTU: SAUCE: SECCOMP: x86: Enable HAVE_ARCH_SECCOMP_FILTER
Enable support for seccomp filter on x86:
- asm/tracehook.h exists
- syscall_get_arguments() works
- syscall_rollback() works
- ptrace_report_syscall() works
- secure_computing() return value is honored (see below)
This also adds support for honoring the return
value from secure_computing().
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>
Signed-off-by: Kees Cook <kees@ubuntu.com>
| -rw-r--r-- | arch/x86/Kconfig | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 7 |
2 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index e32329977f5..faab3f5cf81 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -81,7 +81,8 @@ config X86 select CLKEVT_I8253 select ARCH_HAVE_NMI_SAFE_CMPXCHG select GENERIC_IOMAP - select DCACHE_WORD_ACCESS + 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 685845cf16e..13b1990c7c5 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; } |