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Commit 0208b944 authored by Kees Cook's avatar Kees Cook
Browse files

s390/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: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linux-s390@vger.kernel.org
parent 375f0183

arch/s390/kernel/ptrace.c

+9 −12
Original line number Diff line number Diff line
@@ -821,15 +821,6 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, 


asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)

{

	long ret = 0;



	/* Do the secure computing check first. */

	if (secure_computing(NULL)) {

		/* seccomp failures shouldn't expose any additional code. */

		ret = -1;

		goto out;

	}



	/*

	 * The sysc_tracesys code in entry.S stored the system

	 * call number to gprs[2].
@@ -843,7 +834,13 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 
		 * the system call and the system call restart handling.

		 */

		clear_pt_regs_flag(regs, PIF_SYSCALL);

		ret = -1;

		return -1;

	}



	/* Do the secure computing check after ptrace. */

	if (secure_computing(NULL)) {

		/* seccomp failures shouldn't expose any additional code. */

		return -1;

	}



	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
@@ -852,8 +849,8 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 
	audit_syscall_entry(regs->gprs[2], regs->orig_gpr2,

			    regs->gprs[3], regs->gprs[4],

			    regs->gprs[5]);

out:

	return ret ?: regs->gprs[2];



	return regs->gprs[2];

}



asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)