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Commit 08ff18e2 authored by Roland McGrath's avatar Roland McGrath
Browse files

x86: ptrace: do not sign-extend orig_ax on write 



The high 32 bits of orig_ax will be ignored when it matters,
so don't fiddle them when setting it.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
parent 18c1e2c8

arch/x86/kernel/ptrace.c

+1 −18
Original line number Diff line number Diff line
@@ -325,16 +325,6 @@ static int putreg(struct task_struct *child, 
		return set_flags(child, value);



#ifdef CONFIG_X86_64

	/*

	 * Orig_ax is really just a flag with small positive and

	 * negative values, so make sure to always sign-extend it

	 * from 32 bits so that it works correctly regardless of

	 * whether we come from a 32-bit environment or not.

	 */

	case offsetof(struct user_regs_struct, orig_ax):

		value = (long) (s32) value;

		break;



	case offsetof(struct user_regs_struct,fs_base):

		if (value >= TASK_SIZE_OF(child))

			return -EIO;
@@ -1121,17 +1111,10 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value) 
	R32(esi, si);

	R32(ebp, bp);

	R32(eax, ax);

	R32(orig_eax, orig_ax);

	R32(eip, ip);

	R32(esp, sp);



	case offsetof(struct user32, regs.orig_eax):

		/*

		 * Sign-extend the value so that orig_eax = -1

		 * causes (long)orig_ax < 0 tests to fire correctly.

		 */

		regs->orig_ax = (long) (s32) value;

		break;



	case offsetof(struct user32, regs.eflags):

		return set_flags(child, value);