X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2Fstrncpy_from_user.c;h=05efc1fa97f08941d763996d38ce08afbbaba459;hb=18b2b11c14a714ed3620fb0bd56e8e193a803b47;hp=e0af6ff73d146cfa3356080ebcb1bbea36cd1f96;hpb=9f86262dcc573ca195488de9ec6e4d6d74288ad3;p=firefly-linux-kernel-4.4.55.git

diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index e0af6ff73d14..05efc1fa97f0 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -1,5 +1,6 @@
 #include <linux/compiler.h>
 #include <linux/export.h>
+#include <linux/thread_info.h>
 #include <linux/uaccess.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
@@ -39,8 +40,8 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long
 		unsigned long c, data;
 
 		/* Fall back to byte-at-a-time if we get a page fault */
-		if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
-			break;
+		unsafe_get_user(c, (unsigned long __user *)(src+res), byte_at_a_time);
+
 		*(unsigned long *)(dst+res) = c;
 		if (has_zero(c, &data, &constants)) {
 			data = prep_zero_mask(c, data, &constants);
@@ -55,8 +56,7 @@ byte_at_a_time:
 	while (max) {
 		char c;
 
-		if (unlikely(__get_user(c,src+res)))
-			return -EFAULT;
+		unsafe_get_user(c,src+res, efault);
 		dst[res] = c;
 		if (!c)
 			return res;
@@ -75,6 +75,7 @@ byte_at_a_time:
 	 * Nope: we hit the address space limit, and we still had more
 	 * characters the caller would have wanted. That's an EFAULT.
 	 */
+efault:
 	return -EFAULT;
 }
 
@@ -107,7 +108,13 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
 	src_addr = (unsigned long)src;
 	if (likely(src_addr < max_addr)) {
 		unsigned long max = max_addr - src_addr;
-		return do_strncpy_from_user(dst, src, count, max);
+		long retval;
+
+		check_object_size(dst, count, false);
+		user_access_begin();
+		retval = do_strncpy_from_user(dst, src, count, max);
+		user_access_end();
+		return retval;
 	}
 	return -EFAULT;
 }