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authorMakar Semyonov <m.semenov@tssltd.ru>2025-09-04 15:28:41 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-09-09 19:02:34 +0200
commit3c26a8d30ed6b53a52a023ec537dc50a6d34a67a (patch)
tree6f7b62cd87c623185523d0b716a3ac69817be3e5
parenta67c6397fcb7e842d3c595243049940970541c48 (diff)
cifs: prevent NULL pointer dereference in UTF16 conversion
commit 70bccd9855dae56942f2b18a08ba137bb54093a0 upstream. There can be a NULL pointer dereference bug here. NULL is passed to __cifs_sfu_make_node without checks, which passes it unchecked to cifs_strndup_to_utf16, which in turn passes it to cifs_local_to_utf16_bytes where '*from' is dereferenced, causing a crash. This patch adds a check for NULL 'src' in cifs_strndup_to_utf16 and returns NULL early to prevent dereferencing NULL pointer. Found by Linux Verification Center (linuxtesting.org) with SVACE Signed-off-by: Makar Semyonov <m.semenov@tssltd.ru> Cc: stable@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/smb/client/cifs_unicode.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/smb/client/cifs_unicode.c b/fs/smb/client/cifs_unicode.c
index 4cc6e0896fad..f8659d36793f 100644
--- a/fs/smb/client/cifs_unicode.c
+++ b/fs/smb/client/cifs_unicode.c
@@ -629,6 +629,9 @@ cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
int len;
__le16 *dst;
+ if (!src)
+ return NULL;
+
len = cifs_local_to_utf16_bytes(src, maxlen, cp);
len += 2; /* NULL */
dst = kmalloc(len, GFP_KERNEL);