smb: client: introduce av_for_each_entry() helper

Use new helper in find_domain_name() and find_timestamp() to avoid
duplicating code.

Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/cifsencrypt.c b/fs/smb/client/cifsencrypt.c
index 7a43daacc81595f3897db6c1f7f68ee47f313363..981897ec4dcd1510936c05d67769afe2814cb1ee 100644 (file)
--- a/fs/smb/client/cifsencrypt.c
+++ b/fs/smb/client/cifsencrypt.c
@@ -315,6 +315,39 @@ build_avpair_blob(struct cifs_ses *ses, const struct nls_table *nls_cp)
        return 0;
 }
 
+#define AV_TYPE(av)            (le16_to_cpu(av->type))
+#define AV_LEN(av)             (le16_to_cpu(av->length))
+#define AV_DATA_PTR(av)        ((void *)av->data)
+
+#define av_for_each_entry(ses, av) \
+       for (av = NULL; (av = find_next_av(ses, av));)
+
+static struct ntlmssp2_name *find_next_av(struct cifs_ses *ses,
+                                         struct ntlmssp2_name *av)
+{
+       u16 len;
+       u8 *end;
+
+       end = (u8 *)ses->auth_key.response + ses->auth_key.len;
+       if (!av) {
+               if (unlikely(!ses->auth_key.response || !ses->auth_key.len))
+                       return NULL;
+               av = (void *)ses->auth_key.response;
+       } else {
+               av = (void *)((u8 *)av + sizeof(*av) + AV_LEN(av));
+       }
+
+       if ((u8 *)av + sizeof(*av) > end)
+               return NULL;
+
+       len = AV_LEN(av);
+       if (AV_TYPE(av) == NTLMSSP_AV_EOL)
+               return NULL;
+       if (!len || (u8 *)av + sizeof(*av) + len > end)
+               return NULL;
+       return av;
+}
+
 /* 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 netbios domain name to be used
@@ -325,49 +358,23 @@ build_avpair_blob(struct cifs_ses *ses, const struct nls_table *nls_cp)
  * may not fail against other (those who are not very particular
  * about target string i.e. for some, just user name might suffice.
  */
-static int
-find_domain_name(struct cifs_ses *ses, const struct nls_table *nls_cp)
+static int find_domain_name(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_NB_DOMAIN_NAME) {
-                       if (!attrsize || attrsize >= CIFS_MAX_DOMAINNAME_LEN)
-                               break;
-                       if (!ses->domainName) {
-                               ses->domainName =
-                                       kmalloc(attrsize + 1, GFP_KERNEL);
-                               if (!ses->domainName)
-                                               return -ENOMEM;
-                               cifs_from_utf16(ses->domainName,
-                                       (__le16 *)blobptr, attrsize, attrsize,
-                                       nls_cp, NO_MAP_UNI_RSVD);
-                               break;
-                       }
+       const struct nls_table *nlsc = ses->local_nls;
+       struct ntlmssp2_name *av;
+       u16 len;
+
+       av_for_each_entry(ses, av) {
+               len = AV_LEN(av);
+               if (AV_TYPE(av) == NTLMSSP_AV_NB_DOMAIN_NAME &&
+                   len < CIFS_MAX_DOMAINNAME_LEN && !ses->domainName) {
+                       ses->domainName = kmalloc(len + 1, GFP_KERNEL);
+                       if (!ses->domainName)
+                               return -ENOMEM;
+                       cifs_from_utf16(ses->domainName, AV_DATA_PTR(av),
+                                       len, len, nlsc, NO_MAP_UNI_RSVD);
                }
-               blobptr += attrsize; /* advance attr  value */
        }
-
        return 0;
 }
 
@@ -377,40 +384,16 @@ find_domain_name(struct cifs_ses *ses, const struct nls_table *nls_cp)
  * as part of ntlmv2 authentication (or local current time as
  * default in case of failure)
  */
-static __le64
-find_timestamp(struct cifs_ses *ses)
+static __le64 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;
+       struct ntlmssp2_name *av;
        struct timespec64 ts;
 
-       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 *((__le64 *)blobptr);
-               }
-               blobptr += attrsize; /* advance attr value */
+       av_for_each_entry(ses, av) {
+               if (AV_TYPE(av) == NTLMSSP_AV_TIMESTAMP &&
+                   AV_LEN(av) == sizeof(u64))
+                       return *((__le64 *)AV_DATA_PTR(av));
        }
-
        ktime_get_real_ts64(&ts);
        return cpu_to_le64(cifs_UnixTimeToNT(ts));
 }
@@ -563,7 +546,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
        if (ses->server->negflavor == CIFS_NEGFLAVOR_EXTENDED) {
                if (!ses->domainName) {
                        if (ses->domainAuto) {
-                               rc = find_domain_name(ses, nls_cp);
+                               rc = find_domain_name(ses);
                                if (rc) {
                                        cifs_dbg(VFS, "error %d finding domain name\n",
                                                 rc);

diff --git a/fs/smb/client/cifspdu.h b/fs/smb/client/cifspdu.h
index ee78bb6741d62ff66a87dcece79d960399fbf539..17202754e6d00a022cbfb75289b0f081148c4be1 100644 (file)
--- a/fs/smb/client/cifspdu.h
+++ b/fs/smb/client/cifspdu.h
@@ -649,7 +649,7 @@ typedef union smb_com_session_setup_andx {
 struct ntlmssp2_name {
        __le16 type;
        __le16 length;
-/*     char   name[length]; */
+       __u8 data[];
 } __attribute__((packed));
 
 struct ntlmv2_resp {