Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH 14/14] um/ptrace: run seccomp after ptrace | Date | Thu, 9 Jun 2016 14:02:04 -0700 |
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Close the hole where ptrace can change a syscall out from under seccomp.
Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: user-mode-linux-devel@lists.sourceforge.net --- arch/um/kernel/skas/syscall.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index 9c5570f0f397..ef4b8f949b51 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -20,12 +20,12 @@ void handle_syscall(struct uml_pt_regs *r) UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp); PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS); - /* Do the secure computing check first; failures should be fast. */ - if (secure_computing(NULL) == -1) + if (syscall_trace_enter(regs)) return; - if (syscall_trace_enter(regs)) - goto out; + /* Do the seccomp check after ptrace; failures should be fast. */ + if (secure_computing(NULL) == -1) + return; /* Update the syscall number after orig_ax has potentially been updated * with ptrace. @@ -37,6 +37,5 @@ void handle_syscall(struct uml_pt_regs *r) PT_REGS_SET_SYSCALL_RETURN(regs, EXECUTE_SYSCALL(syscall, regs)); -out: syscall_trace_leave(regs); } -- 2.7.4
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