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Commit ab29b33a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'seccomp-v4.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux 

Pull seccomp fixes from Kees Cook:
 "Fix UM seccomp vs ptrace, after reordering landed"

* tag 'seccomp-v4.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  seccomp: Remove 2-phase API documentation
  um/ptrace: Fix the syscall number update after a ptrace
  um/ptrace: Fix the syscall_trace_leave call
parents 08411a75 4fadd04d

arch/Kconfig

+0 −11
Original line number Diff line number Diff line
@@ -336,17 +336,6 @@ config HAVE_ARCH_SECCOMP_FILTER 
	    results in the system call being skipped immediately.

	  - seccomp syscall wired up



	  For best performance, an arch should use seccomp_phase1 and

	  seccomp_phase2 directly.  It should call seccomp_phase1 for all

	  syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not

	  need to be called from a ptrace-safe context.  It must then

	  call seccomp_phase2 if seccomp_phase1 returns anything other

	  than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.



	  As an additional optimization, an arch may provide seccomp_data

	  directly to seccomp_phase1; this avoids multiple calls

	  to the syscall_xyz helpers for every syscall.



config SECCOMP_FILTER

	def_bool y

	depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET

arch/um/kernel/skas/syscall.c

+3 −7
Original line number Diff line number Diff line
@@ -21,21 +21,17 @@ 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.

	 */

	UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);

	syscall = UPT_SYSCALL_NR(r);



	if (syscall >= 0 && syscall <= __NR_syscall_max)

		PT_REGS_SET_SYSCALL_RETURN(regs,

				EXECUTE_SYSCALL(syscall, regs));



out:

	syscall_trace_leave(regs);

}

arch/x86/um/ptrace_32.c

+3 −0
Original line number Diff line number Diff line
@@ -84,7 +84,10 @@ int putreg(struct task_struct *child, int regno, unsigned long value) 
	case EAX:

	case EIP:

	case UESP:

		break;

	case ORIG_EAX:

		/* Update the syscall number. */

		UPT_SYSCALL_NR(&child->thread.regs.regs) = value;

		break;

	case FS:

		if (value && (value & 3) != 3)

arch/x86/um/ptrace_64.c

+4 −0
Original line number Diff line number Diff line
@@ -78,7 +78,11 @@ int putreg(struct task_struct *child, int regno, unsigned long value) 
	case RSI:

	case RDI:

	case RBP:

		break;



	case ORIG_RAX:

		/* Update the syscall number. */

		UPT_SYSCALL_NR(&child->thread.regs.regs) = value;

		break;



	case FS: