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Commit 616fe993 authored by Dave Martin's avatar Dave Martin Committed by Greg Kroah-Hartman
Browse files

h8300/ptrace: Fix incorrect register transfer count 



commit 502585c7555083d4a949c08350306b9ec196779e upstream.

regs_set() and regs_get() are vulnerable to an off-by-1 buffer overrun
if CONFIG_CPU_H8S is set, since this adds an extra entry to
register_offset[] but not to user_regs_struct.

So, iterate over user_regs_struct based on its actual size, not based on
the length of register_offset[].

Signed-off-by: default avatarDave Martin <Dave.Martin@arm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d77bd2d6

arch/h8300/kernel/ptrace.c

+5 −3
Original line number Diff line number Diff line
@@ -95,7 +95,8 @@ static int regs_get(struct task_struct *target, 
	long *reg = (long *)&regs;



	/* build user regs in buffer */

	for (r = 0; r < ARRAY_SIZE(register_offset); r++)

	BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0);

	for (r = 0; r < sizeof(regs) / sizeof(long); r++)

		*reg++ = h8300_get_reg(target, r);



	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
@@ -113,7 +114,8 @@ static int regs_set(struct task_struct *target, 
	long *reg;



	/* build user regs in buffer */

	for (reg = (long *)&regs, r = 0; r < ARRAY_SIZE(register_offset); r++)

	BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0);

	for (reg = (long *)&regs, r = 0; r < sizeof(regs) / sizeof(long); r++)

		*reg++ = h8300_get_reg(target, r);



	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
@@ -122,7 +124,7 @@ static int regs_set(struct task_struct *target, 
		return ret;



	/* write back to pt_regs */

	for (reg = (long *)&regs, r = 0; r < ARRAY_SIZE(register_offset); r++)

	for (reg = (long *)&regs, r = 0; r < sizeof(regs) / sizeof(long); r++)

		h8300_put_reg(target, r, *reg++);

	return 0;

}