[PATCH 14/14] um/ptrace: run seccomp after ptrace
From: Kees Cook <hidden>
Date: 2016-06-09 21:05:55
Also in:
linux-arch, linux-arm-kernel, linux-s390, linux-um, linuxppc-dev, lkml
Subsystem:
the rest, user-mode linux (uml) · Maintainers:
Linus Torvalds, Richard Weinberger, Anton Ivanov, Johannes Berg
Close the hole where ptrace can change a syscall out from under seccomp. Signed-off-by: Kees Cook <redacted> Cc: Jeff Dike <redacted> 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