From c6cfbeb4029610c8c330c312dcf4d514cc067554 Mon Sep 17 00:00:00 2001 From: Will Drewry Date: Thu, 12 Apr 2012 16:48:03 -0500 Subject: 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 Reviewed-by: H. Peter Anvin Acked-by: Eric Paris Reviewed-by: Kees Cook 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 --- arch/x86/kernel/ptrace.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/ptrace.c') 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; } -- cgit v1.2.3 From bad1a753d4d4deb09d4bc0bac1dd4fc3298502e9 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 21 May 2012 20:29:45 -0700 Subject: x86, x32, ptrace: Remove PTRACE_ARCH_PRCTL for x32 When I added x32 ptrace to 3.4 kernel, I also include PTRACE_ARCH_PRCTL support for x32 GDB For ARCH_GET_FS/GS, it takes a pointer to int64. But at user level, ARCH_GET_FS/GS takes a pointer to int32. So I have to add x32 ptrace to glibc to handle it with a temporary int64 passed to kernel and copy it back to GDB as int32. Roland suggested that PTRACE_ARCH_PRCTL is obsolete and x32 GDB should use fs_base and gs_base fields of user_regs_struct instead. Accordingly, remove PTRACE_ARCH_PRCTL completely from the x32 code to avoid possible memory overrun when pointer to int32 is passed to kernel. Link: http://lkml.kernel.org/r/CAMe9rOpDzHfS7NH7m1vmD9QRw8SSj4Sc%2BaNOgcWm_WJME2eRsQ@mail.gmail.com Signed-off-by: H. Peter Anvin Cc: v3.4 --- arch/x86/kernel/ptrace.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'arch/x86/kernel/ptrace.c') diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 13b1990c7c58..c4c6a5c2bf0f 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -1211,12 +1211,6 @@ static long x32_arch_ptrace(struct task_struct *child, 0, sizeof(struct user_i387_struct), datap); - /* normal 64bit interface to access TLS data. - Works just like arch_prctl, except that the arguments - are reversed. */ - case PTRACE_ARCH_PRCTL: - return do_arch_prctl(child, data, addr); - default: return compat_ptrace_request(child, request, addr, data); } -- cgit v1.2.3