diff options
authorMark Salter <>2011-10-04 09:17:36 -0400
committerMark Salter <>2011-10-06 19:47:12 -0400
commit830f5800acae17b972d264ab65fe54a7f10c1d82 (patch)
parent3ee72ca99288f1de95ec9c570e43f531c8799f06 (diff)
fix default __strnlen_user macro
The existing __strnlen_user macro simply resolved to strnlen. However, the count returned by strnlen_user should include the NULL byte. This patch fixes the __strnlen_user macro to include the NULL byte in the count. Signed-off-by: Mark Salter <> Acked-by: Arnd Bergmann <>
1 files changed, 6 insertions, 1 deletions
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index ac68c999b6c2..9788568f7978 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -289,9 +289,14 @@ strncpy_from_user(char *dst, const char __user *src, long count)
* Return 0 on exception, a value greater than N if too long
#ifndef __strnlen_user
-#define __strnlen_user strnlen
+#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
+ * Unlike strnlen, strnlen_user includes the nul terminator in
+ * its returned count. Callers should check for a returned value
+ * greater than N as an indication the string is too long.
+ */
static inline long strnlen_user(const char __user *src, long n)
if (!access_ok(VERIFY_READ, src, 1))