iovec: make sure the caller actually wants anything in memcpy_fromiov…

…ecend [ Upstream commit 06ebb06 ] Check for cases when the caller requests 0 bytes instead of running off and dereferencing potentially invalid iovecs. Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
fkwp · Aug 14, 2014 · 8fbbef0 · 8fbbef0
1 parent 80db167
commit 8fbbef0
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/net/core/iovec.c b/net/core/iovec.c
@@ -157,6 +157,10 @@ EXPORT_SYMBOL(memcpy_fromiovec);
 int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
 			int offset, int len)
 {
+	/* No data? Done! */
+	if (len == 0)
+		return 0;
+
 	/* Skip over the finished iovecs */
 	while (offset >= iov->iov_len) {
 		offset -= iov->iov_len;