From: Len Baker len.baker@gmx.com
[ Upstream commit f980d055a0f858d73d9467bb0b570721bbfcdfb8 ]
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 len.baker@gmx.com Reviewed-by: Paulo Alcantara (SUSE) pc@cjr.nz Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 9986817532b1..7932e20555d2 100644 --- a/fs/cifs/cifs_unicode.c +++ b/fs/cifs/cifs_unicode.c @@ -371,14 +371,9 @@ 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;