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Commit 26703c63 authored by Kees Cook's avatar Kees Cook
Browse files

um/ptrace: run seccomp after ptrace 



Close the hole where ptrace can change a syscall out from under seccomp.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: user-mode-linux-devel@lists.sourceforge.net
parent 635efc70

arch/um/kernel/skas/syscall.c

+4 −5
Original line number Diff line number Diff line
@@ -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);

}