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Commit 2545e5da authored by Al Viro's avatar Al Viro
Browse files

asm-generic: make copy_from_user() zero the destination properly 



... in all cases, including the failing access_ok()

Note that some architectures using asm-generic/uaccess.h have
__copy_from_user() not zeroing the tail on failure halfway
through.  This variant works either way.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 2561d309

include/asm-generic/uaccess.h

+6 −4
Original line number Original line Diff line number Diff line
@@ -257,11 +257,13 @@ extern int __get_user_bad(void) __attribute__((noreturn)); 
static inline long copy_from_user(void *to,

static inline long copy_from_user(void *to,

		const void __user * from, unsigned long n)

		const void __user * from, unsigned long n)

{

{

	unsigned long res = n;

	might_fault();

	might_fault();

	if (access_ok(VERIFY_READ, from, n))

	if (likely(access_ok(VERIFY_READ, from, n)))

		return __copy_from_user(to, from, n);

		res = __copy_from_user(to, from, n);

	else

	if (unlikely(res))

		return n;

		memset(to + (n - res), 0, res);

	return res;

}

}





static inline long copy_to_user(void __user *to,

static inline long copy_to_user(void __user *to,