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authorKees Cook <keescook@chromium.org>2016-06-02 19:59:42 -0700
committerKees Cook <keescook@chromium.org>2016-06-14 10:54:47 -0700
commit26703c636c1f3272b39bd0f6d04d2e970984f1b6 (patch)
treea23cb02922fdac007e7d97d9d4f40ef12bf0893e /arch/um/kernel
parent635efc702984857b45a2a2491ed7a529e14cbdf9 (diff)
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um/ptrace: run seccomp after ptrace
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
Diffstat (limited to 'arch/um/kernel')
-rw-r--r--arch/um/kernel/skas/syscall.c9
1 files 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);
}