NFS: Be more careful about mapping file permissions

[karo-tx-linux.git] / fs / nfs / dir.c

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 90bc4025ca3cbb6efb4e5b9d02981262d702acdd..37a6180ee2e8dcc80911bf1302324644fd20fb01 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1518,7 +1518,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
                d_drop(dentry);
                switch (err) {
                case -ENOENT:
-                       d_add(dentry, NULL);
+                       d_splice_alias(NULL, dentry);
                        nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
                        break;
                case -EISDIR:
@@ -2375,16 +2375,40 @@ void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
 }
 EXPORT_SYMBOL_GPL(nfs_access_add_cache);
 
+#define NFS_MAY_READ (NFS4_ACCESS_READ)
+#define NFS_MAY_WRITE (NFS4_ACCESS_MODIFY | \
+               NFS4_ACCESS_EXTEND | \
+               NFS4_ACCESS_DELETE)
+#define NFS_FILE_MAY_WRITE (NFS4_ACCESS_MODIFY | \
+               NFS4_ACCESS_EXTEND)
+#define NFS_DIR_MAY_WRITE NFS_MAY_WRITE
+#define NFS_MAY_LOOKUP (NFS4_ACCESS_LOOKUP)
+#define NFS_MAY_EXECUTE (NFS4_ACCESS_EXECUTE)
+static int
+nfs_access_calc_mask(u32 access_result, umode_t umode)
+{
+       int mask = 0;
+
+       if (access_result & NFS_MAY_READ)
+               mask |= MAY_READ;
+       if (S_ISDIR(umode)) {
+               if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE)
+                       mask |= MAY_WRITE;
+               if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP)
+                       mask |= MAY_EXEC;
+       } else if (S_ISREG(umode)) {
+               if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE)
+                       mask |= MAY_WRITE;
+               if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE)
+                       mask |= MAY_EXEC;
+       } else if (access_result & NFS_MAY_WRITE)
+                       mask |= MAY_WRITE;
+       return mask;
+}
+
 void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result)
 {
-       entry->mask = 0;
-       if (access_result & NFS4_ACCESS_READ)
-               entry->mask |= MAY_READ;
-       if (access_result &
-           (NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE))
-               entry->mask |= MAY_WRITE;
-       if (access_result & (NFS4_ACCESS_LOOKUP|NFS4_ACCESS_EXECUTE))
-               entry->mask |= MAY_EXEC;
+       entry->mask = access_result;
 }
 EXPORT_SYMBOL_GPL(nfs_access_set_mask);
 
@@ -2392,6 +2416,7 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
 {
        struct nfs_access_entry cache;
        bool may_block = (mask & MAY_NOT_BLOCK) == 0;
+       int cache_mask;
        int status;
 
        trace_nfs_access_enter(inode);
@@ -2407,7 +2432,8 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
                goto out;
 
        /* Be clever: ask server to check for all possible rights */
-       cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
+       cache.mask = NFS_MAY_LOOKUP | NFS_MAY_EXECUTE
+                    | NFS_MAY_WRITE | NFS_MAY_READ;
        cache.cred = cred;
        cache.jiffies = jiffies;
        status = NFS_PROTO(inode)->access(inode, &cache);
@@ -2421,7 +2447,8 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
        }
        nfs_access_add_cache(inode, &cache);
 out_cached:
-       if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
+       cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode);
+       if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
                status = -EACCES;
 out:
        trace_nfs_access_exit(inode, status);