Commit 972939e2 authored Aug 01, 2016 by Mickaël Salaün Committed by Kees Cook Sep 07, 2016

um/ptrace: Fix the syscall_trace_leave call



Keep the same semantic as before the commit 26703c63: deallocate
audit context and fake a proper syscall exit.

This fix a kernel panic triggered by the seccomp_bpf test:
> [ RUN      ] global.ERRNO_valid
> BUG: failure at kernel/auditsc.c:1504/__audit_syscall_entry()!
> Kernel panic - not syncing: BUG!

Fixes: 26703c63 ("um/ptrace: run seccomp after ptrace")

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: James Morris <jmorris@namei.org>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

parent d060e0f6

arch/um/kernel/skas/syscall.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -21,11 +21,11 @@ void handle_syscall(struct uml_pt_regs *r)
		PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);

		if (syscall_trace_enter(regs))
		return;
		goto out;

		/* Do the seccomp check after ptrace; failures should be fast. */
		if (secure_computing(NULL) == -1)
		return;
		goto out;

		/* Update the syscall number after orig_ax has potentially been updated
		* with ptrace.
		@@ -37,5 +37,6 @@ void handle_syscall(struct uml_pt_regs *r)
		PT_REGS_SET_SYSCALL_RETURN(regs,
		EXECUTE_SYSCALL(syscall, regs));

		out:
		syscall_trace_leave(regs);
		}