1 files changed, 20 insertions, 29 deletions

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index fc783e264420..0fb15bbbe43c 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -225,6 +225,13 @@ sid_to_str(struct cifs_sid *sidptr, char *sidstr)
 }
 
 static void
+cifs_copy_sid(struct cifs_sid *dst, const struct cifs_sid *src)
+{
+        memcpy(dst, src, sizeof(*dst));
+        dst->num_subauth = min_t(u8, src->num_subauth, NUM_SUBAUTHS);
+}
+
+static void
 id_rb_insert(struct rb_root *root, struct cifs_sid *sidptr,
                 struct cifs_sid_id **psidid, char *typestr)
 {
@@ -248,7 +255,7 @@ id_rb_insert(struct rb_root *root, struct cifs_sid *sidptr,
                 }
         }
 
-        memcpy(&(*psidid)->sid, sidptr, sizeof(struct cifs_sid));
+        cifs_copy_sid(&(*psidid)->sid, sidptr);
         (*psidid)->time = jiffies - (SID_MAP_RETRY + 1);
         (*psidid)->refcount = 0;
 
@@ -354,7 +361,7 @@ id_to_sid(unsigned long cid, uint sidtype, struct cifs_sid *ssid)
          * any fields of the node after a reference is put .
          */
         if (test_bit(SID_ID_MAPPED, &psidid->state)) {
-                memcpy(ssid, &psidid->sid, sizeof(struct cifs_sid));
+                cifs_copy_sid(ssid, &psidid->sid);
                 psidid->time = jiffies; /* update ts for accessing */
                 goto id_sid_out;
         }
@@ -370,14 +377,14 @@ id_to_sid(unsigned long cid, uint sidtype, struct cifs_sid *ssid)
                 if (IS_ERR(sidkey)) {
                         rc = -EINVAL;
                         cFYI(1, "%s: Can't map and id to a SID", __func__);
+                } else if (sidkey->datalen < sizeof(struct cifs_sid)) {
+                        rc = -EIO;
+                        cFYI(1, "%s: Downcall contained malformed key "
+                                "(datalen=%hu)", __func__, sidkey->datalen);
                 } else {
                         lsid = (struct cifs_sid *)sidkey->payload.data;
-                        memcpy(&psidid->sid, lsid,
-                                sidkey->datalen < sizeof(struct cifs_sid) ?
-                                sidkey->datalen : sizeof(struct cifs_sid));
-                        memcpy(ssid, &psidid->sid,
-                                sidkey->datalen < sizeof(struct cifs_sid) ?
-                                sidkey->datalen : sizeof(struct cifs_sid));
+                        cifs_copy_sid(&psidid->sid, lsid);
+                        cifs_copy_sid(ssid, &psidid->sid);
                         set_bit(SID_ID_MAPPED, &psidid->state);
                         key_put(sidkey);
                         kfree(psidid->sidstr);
@@ -396,7 +403,7 @@ id_to_sid(unsigned long cid, uint sidtype, struct cifs_sid *ssid)
                         return rc;
                 }
                 if (test_bit(SID_ID_MAPPED, &psidid->state))
-                        memcpy(ssid, &psidid->sid, sizeof(struct cifs_sid));
+                        cifs_copy_sid(ssid, &psidid->sid);
                 else
                         rc = -EINVAL;
         }
@@ -675,8 +682,6 @@ int compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid)
 static void copy_sec_desc(const struct cifs_ntsd *pntsd,
                                 struct cifs_ntsd *pnntsd, __u32 sidsoffset)
 {
-        int i;
-
         struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
         struct cifs_sid *nowner_sid_ptr, *ngroup_sid_ptr;
 
@@ -692,26 +697,14 @@ static void copy_sec_desc(const struct cifs_ntsd *pntsd,
         owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
                                 le32_to_cpu(pntsd->osidoffset));
         nowner_sid_ptr = (struct cifs_sid *)((char *)pnntsd + sidsoffset);
-
-        nowner_sid_ptr->revision = owner_sid_ptr->revision;
-        nowner_sid_ptr->num_subauth = owner_sid_ptr->num_subauth;
-        for (i = 0; i < 6; i++)
-                nowner_sid_ptr->authority[i] = owner_sid_ptr->authority[i];
-        for (i = 0; i < 5; i++)
-                nowner_sid_ptr->sub_auth[i] = owner_sid_ptr->sub_auth[i];
+        cifs_copy_sid(nowner_sid_ptr, owner_sid_ptr);
 
         /* copy group sid */
         group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
                                 le32_to_cpu(pntsd->gsidoffset));
         ngroup_sid_ptr = (struct cifs_sid *)((char *)pnntsd + sidsoffset +
                                         sizeof(struct cifs_sid));
-
-        ngroup_sid_ptr->revision = group_sid_ptr->revision;
-        ngroup_sid_ptr->num_subauth = group_sid_ptr->num_subauth;
-        for (i = 0; i < 6; i++)
-                ngroup_sid_ptr->authority[i] = group_sid_ptr->authority[i];
-        for (i = 0; i < 5; i++)
-                ngroup_sid_ptr->sub_auth[i] = group_sid_ptr->sub_auth[i];
+        cifs_copy_sid(ngroup_sid_ptr, group_sid_ptr);
 
         return;
 }
@@ -1120,8 +1113,7 @@ static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
                                 kfree(nowner_sid_ptr);
                                 return rc;
                         }
-                        memcpy(owner_sid_ptr, nowner_sid_ptr,
-                                        sizeof(struct cifs_sid));
+                        cifs_copy_sid(owner_sid_ptr, nowner_sid_ptr);
                         kfree(nowner_sid_ptr);
                         *aclflag = CIFS_ACL_OWNER;
                 }
@@ -1139,8 +1131,7 @@ static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
                                 kfree(ngroup_sid_ptr);
                                 return rc;
                         }
-                        memcpy(group_sid_ptr, ngroup_sid_ptr,
-                                        sizeof(struct cifs_sid));
+                        cifs_copy_sid(group_sid_ptr, ngroup_sid_ptr);
                         kfree(ngroup_sid_ptr);
                         *aclflag = CIFS_ACL_GROUP;
                 }