From f980d055a0f858d73d9467bb0b570721bbfcdfb8 Mon Sep 17 00:00:00 2001 From: Len Baker Date: Tue, 17 Aug 2021 12:27:09 +0200 Subject: [PATCH] CIFS: Fix a potencially linear read overflow strlcpy() reads the entire source buffer first. This read may exceed the destination size limit. This is both inefficient and can lead to linear read overflows if a source string is not NUL-terminated. Also, the strnlen() call does not avoid the read overflow in the strlcpy function when a not NUL-terminated string is passed. So, replace this block by a call to kstrndup() that avoids this type of overflow and does the same. Fixes: 066ce6899484d ("cifs: rename cifs_strlcpy_to_host and make it use new functions") Signed-off-by: Len Baker Reviewed-by: Paulo Alcantara (SUSE) Reviewed-by: Jeff Layton Signed-off-by: Steve French --- fs/cifs/cifs_unicode.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/fs/cifs/cifs_unicode.c b/fs/cifs/cifs_unicode.c index 9bd03a231032..171ad8b42107 100644 --- a/fs/cifs/cifs_unicode.c +++ b/fs/cifs/cifs_unicode.c @@ -358,14 +358,9 @@ cifs_strndup_from_utf16(const char *src, const int maxlen, if (!dst) return NULL; cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage, - NO_MAP_UNI_RSVD); + NO_MAP_UNI_RSVD); } else { - len = strnlen(src, maxlen); - len++; - dst = kmalloc(len, GFP_KERNEL); - if (!dst) - return NULL; - strlcpy(dst, src, len); + dst = kstrndup(src, maxlen, GFP_KERNEL); } return dst; -- 2.39.5