Linux cifs mount with ntlmssp against an Mac OS X (Yosemite
10.10.5) share fails in case the clocks differ more than +/-2h:
digest-service: digest-request: od failed with 2 proto=ntlmv2
digest-service: digest-request: kdc failed with -1561745592 proto=ntlmv2
Fix this by (re-)using the given server timestamp for the
ntlmv2 authentication (as Windows 7 does).
Signed-off-by: Peter Seiderer <ps.report@xxxxxxx>
---
fs/cifs/cifsencrypt.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 51 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index aa0dc25..e6bfa92 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -444,6 +444,48 @@ find_domain_name(struct cifs_ses *ses, const struct nls_table *nls_cp)
return 0;
}
+/* Server has provided av pairs/target info in the type 2 challenge
+ * packet and we have plucked it and stored within smb session.
+ * We parse that blob here to find the server given timestamp
+ * as part of ntlmv2 authentication (or local current time as
+ * default in case of failure)
+ */
+static u64
+find_timestamp(struct cifs_ses *ses)
+{
+ unsigned int attrsize;
+ unsigned int type;
+ unsigned int onesize = sizeof(struct ntlmssp2_name);
+ unsigned char *blobptr;
+ unsigned char *blobend;
+ struct ntlmssp2_name *attrptr;
+
+ if (!ses->auth_key.len || !ses->auth_key.response)
+ return 0;
+
+ blobptr = ses->auth_key.response;
+ blobend = blobptr + ses->auth_key.len;
+
+ while (blobptr + onesize < blobend) {
+ attrptr = (struct ntlmssp2_name *) blobptr;
+ type = le16_to_cpu(attrptr->type);
+ if (type == NTLMSSP_AV_EOL)
+ break;
+ blobptr += 2; /* advance attr type */
+ attrsize = le16_to_cpu(attrptr->length);
+ blobptr += 2; /* advance attr size */
+ if (blobptr + attrsize > blobend)
+ break;
+ if (type == NTLMSSP_AV_TIMESTAMP) {
+ if (attrsize == sizeof(u64))
+ return *((u64 *)blobptr);
+ }
+ blobptr += attrsize; /* advance attr value */
+ }
+
+ return cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
+}
+
static int calc_ntlmv2_hash(struct cifs_ses *ses, char *ntlmv2_hash,
const struct nls_table *nls_cp)
{
@@ -641,6 +683,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
struct ntlmv2_resp *ntlmv2;
char ntlmv2_hash[16];
unsigned char *tiblob = NULL; /* target info blob */
+ u64 rsp_timestamp;
if (ses->server->negflavor == CIFS_NEGFLAVOR_EXTENDED) {
if (!ses->domainName) {
@@ -659,6 +702,12 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
}
}
+ /* Must be within 5 minutes of the server (or in range +/-2h
+ * in case of Mac OS X), so simply carry over server timestamp
+ * (as Windows 7 does)
+ */
+ rsp_timestamp = find_timestamp(ses);
+
baselen = CIFS_SESS_KEY_SIZE + sizeof(struct ntlmv2_resp);
tilen = ses->auth_key.len;
tiblob = ses->auth_key.response;
@@ -675,8 +724,8 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
(ses->auth_key.response + CIFS_SESS_KEY_SIZE);
ntlmv2->blob_signature = cpu_to_le32(0x00000101);
ntlmv2->reserved = 0;
- /* Must be within 5 minutes of the server */
- ntlmv2->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
+ ntlmv2->time = rsp_timestamp;
+
get_random_bytes(&ntlmv2->client_chal, sizeof(ntlmv2->client_chal));
ntlmv2->reserved2 = 0;
--
2.1.4
--
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