[CIFS] If no Access Control Entries, set mode perm bits to zero

Also clean up ACL code

Acked-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 55 insertions, 22 deletions

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index f1215df7fbee..bd75a3b8caff 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -223,6 +223,17 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
                 le32_to_cpu(pdacl->num_aces)));
 #endif
 
+        /* reset rwx permissions for user/group/other.
+           Also, if num_aces is 0 i.e. DACL has no ACEs,
+           user/group/other have no permissions */
+        inode->i_mode &= ~(S_IRWXUGO);
+
+        if (!pdacl) {
+                /* no DACL in the security descriptor, set
+                   all the permissions for user/group/other */
+                inode->i_mode |= S_IRWXUGO;
+                return;
+        }
         acl_base = (char *)pdacl;
         acl_size = sizeof(struct cifs_acl);
 
@@ -235,9 +246,6 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
                 cifscred->aces = kmalloc(num_aces *
                         sizeof(struct cifs_ace *), GFP_KERNEL);*/
 
-                /* reset rwx permissions for user/group/other */
-                inode->i_mode &= ~(S_IRWXUGO);
-
                 for (i = 0; i < num_aces; ++i) {
                         ppace[i] = (struct cifs_ace *) (acl_base + acl_size);
 #ifdef CONFIG_CIFS_DEBUG2
@@ -309,6 +317,7 @@ static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
         struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
         struct cifs_acl *dacl_ptr; /* no need for SACL ptr */
         char *end_of_acl = ((char *)pntsd) + acl_len;
+        __u32 dacloffset;
 
         if ((inode == NULL) || (pntsd == NULL))
                 return -EIO;
@@ -317,15 +326,14 @@ static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
                                 le32_to_cpu(pntsd->osidoffset));
         group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
                                 le32_to_cpu(pntsd->gsidoffset));
-        dacl_ptr = (struct cifs_acl *)((char *)pntsd +
-                                le32_to_cpu(pntsd->dacloffset));
+        dacloffset = le32_to_cpu(pntsd->dacloffset);
+        dacl_ptr = (struct cifs_acl *)(char *)pntsd + dacloffset;
 #ifdef CONFIG_CIFS_DEBUG2
         cFYI(1, ("revision %d type 0x%x ooffset 0x%x goffset 0x%x "
                  "sacloffset 0x%x dacloffset 0x%x",
                  pntsd->revision, pntsd->type, le32_to_cpu(pntsd->osidoffset),
                  le32_to_cpu(pntsd->gsidoffset),
-                 le32_to_cpu(pntsd->sacloffset),
-                 le32_to_cpu(pntsd->dacloffset)));
+                 le32_to_cpu(pntsd->sacloffset), dacloffset));
 #endif
 /*      cifs_dump_mem("owner_sid: ", owner_sid_ptr, 64); */
         rc = parse_sid(owner_sid_ptr, end_of_acl);
@@ -336,7 +344,11 @@ static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
         if (rc)
                 return rc;
 
-        parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr, group_sid_ptr, inode);
+        if (dacloffset)
+                parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr,
+                group_sid_ptr, inode);
+        else
+                cFYI(1, ("no ACL")); /* BB grant all or default perms? */
 
 /*      cifscred->uid = owner_sid_ptr->rid;
         cifscred->gid = group_sid_ptr->rid;
@@ -350,9 +362,9 @@ static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
 }
 
 
-/* Translate the CIFS ACL (simlar to NTFS ACL) for a file into mode bits */
-
-void acl_to_uid_mode(struct inode *inode, const char *path)
+/* Retrieve an ACL from the server */
+static struct cifs_ntsd *get_cifs_acl(u32 *pacllen, struct inode *inode,
+                                       const char *path)
 {
         struct cifsFileInfo *open_file;
         int unlock_file = FALSE;
@@ -362,19 +374,18 @@ void acl_to_uid_mode(struct inode *inode, const char *path)
         struct super_block *sb;
         struct cifs_sb_info *cifs_sb;
         struct cifs_ntsd *pntsd = NULL;
-        __u32 acllen;
 
         cFYI(1, ("get mode from ACL for %s", path));
 
         if (inode == NULL)
-                return;
+                return NULL;
 
         xid = GetXid();
         open_file = find_readable_file(CIFS_I(inode));
         sb = inode->i_sb;
         if (sb == NULL) {
                 FreeXid(xid);
-                return;
+                return NULL;
         }
         cifs_sb = CIFS_SB(sb);
 
@@ -391,25 +402,44 @@ void acl_to_uid_mode(struct inode *inode, const char *path)
                 if (rc != 0) {
                         cERROR(1, ("Unable to open file to get ACL"));
                         FreeXid(xid);
-                        return;
+                        return NULL;
                 }
         }
 
-        rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, &acllen);
-        cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, acllen));
+        rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, pacllen);
+        cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, *pacllen));
         if (unlock_file == TRUE)
                 atomic_dec(&open_file->wrtPending);
         else
                 CIFSSMBClose(xid, cifs_sb->tcon, fid);
 
-        /* parse ACEs */
-        if (!rc)
+        FreeXid(xid);
+        return pntsd;
+}
+
+/* Translate the CIFS ACL (simlar to NTFS ACL) for a file into mode bits */
+void acl_to_uid_mode(struct inode *inode, const char *path)
+{
+        struct cifs_ntsd *pntsd = NULL;
+        u32 acllen = 0;
+        int rc = 0;
+
+#ifdef CONFIG_CIFS_DEBUG2
+        cFYI(1, ("converting ACL to mode for %s", path));
+#endif
+        pntsd = get_cifs_acl(&acllen, inode, path);
+
+        /* if we can retrieve the ACL, now parse Access Control Entries, ACEs */
+        if (pntsd)
                 rc = parse_sec_desc(pntsd, acllen, inode);
+        if (rc)
+                cFYI(1, ("parse sec desc failed rc = %d", rc));
+
         kfree(pntsd);
-        FreeXid(xid);
         return;
 }
 
+/* Convert mode bits to an ACL so we can update the ACL on the server */
 int mode_to_acl(struct inode *inode, const char *path)
 {
         int rc = 0;
@@ -419,12 +449,15 @@ int mode_to_acl(struct inode *inode, const char *path)
         cFYI(1, ("set ACL from mode for %s", path));
 
         /* Get the security descriptor */
+        pntsd = get_cifs_acl(&acllen, inode, path);
 
-        /* Add/Modify the three ACEs for owner, group, everyone */
+        /* Add/Modify the three ACEs for owner, group, everyone
+           while retaining the other ACEs */
 
         /* Set the security descriptor */
-        kfree(pntsd);
 
+
+        kfree(pntsd);
         return rc;
 }
 #endif /* CONFIG_CIFS_EXPERIMENTAL */