From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Wed, 12 Dec 2018 11:50:00 +1000
Subject: [PATCH] cifs: remove coverity warning in calc_lanman_hash
Git-commit: 52baa51d30573273341b78a3e3ed0d9a845d3e55
Patch-mainline: v5.0-rc1
References: bsc#1144333

password_with_pad is a fixed size buffer of 16 bytes, it contains a
password string, to be padded with \0 if shorter than 16 bytes
but is just truncated if longer.
It is not, and we do not depend on it to be, nul terminated.

As such, do not use strncpy() to populate this buffer since
the str* prefix suggests that this is a string, which it is not,
and it also confuses coverity causing a false warning.

Detected by CoverityScan CID#113743 ("Buffer not null terminated")

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
---
 fs/cifs/cifsencrypt.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index ecdff344e8fe..d2a05e46d6f5 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -304,12 +304,17 @@ int setup_ntlm_response(struct cifs_ses *ses, const struct nls_table *nls_cp)
 int calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
 			char *lnm_session_key)
 {
-	int i;
+	int i, len;
 	int rc;
 	char password_with_pad[CIFS_ENCPWD_SIZE] = {0};
 
-	if (password)
-		strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE);
+	if (password) {
+		for (len = 0; len < CIFS_ENCPWD_SIZE; len++)
+			if (!password[len])
+				break;
+
+		memcpy(password_with_pad, password, len);
+	}
 
 	if (!encrypt && global_secflags & CIFSSEC_MAY_PLNTXT) {
 		memcpy(lnm_session_key, password_with_pad,
-- 
2.16.4