1 files changed, 21 insertions, 13 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 9802345df5e7..0223c41fb114 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -238,7 +238,8 @@ int generic_permission(struct inode *inode, int mask, unsigned int flags,
 
         /*
          * Read/write DACs are always overridable.
-         * Executable DACs are overridable if at least one exec bit is set.
+         * Executable DACs are overridable for all directories and
+         * for non-directories that have least one exec bit set.
          */
         if (!(mask & MAY_EXEC) || execute_ok(inode))
                 if (ns_capable(inode_userns(inode), CAP_DAC_OVERRIDE))
@@ -812,6 +813,11 @@ static int follow_automount(struct path *path, unsigned flags,
         if (!mnt) /* mount collision */
                 return 0;
 
+        if (!*need_mntput) {
+                /* lock_mount() may release path->mnt on error */
+                mntget(path->mnt);
+                *need_mntput = true;
+        }
         err = finish_automount(mnt, path);
 
         switch (err) {
@@ -819,12 +825,9 @@ static int follow_automount(struct path *path, unsigned flags,
                 /* Someone else made a mount here whilst we were busy */
                 return 0;
         case 0:
-                dput(path->dentry);
-                if (*need_mntput)
-                        mntput(path->mnt);
+                path_put(path);
                 path->mnt = mnt;
                 path->dentry = dget(mnt->mnt_root);
-                *need_mntput = true;
                 return 0;
         default:
                 return err;
@@ -844,9 +847,10 @@ static int follow_automount(struct path *path, unsigned flags,
  */
 static int follow_managed(struct path *path, unsigned flags)
 {
+        struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */
         unsigned managed;
         bool need_mntput = false;
-        int ret;
+        int ret = 0;
 
         /* Given that we're not holding a lock here, we retain the value in a
          * local variable for each dentry as we look at it so that we don't see
@@ -861,7 +865,7 @@ static int follow_managed(struct path *path, unsigned flags)
                         BUG_ON(!path->dentry->d_op->d_manage);
                         ret = path->dentry->d_op->d_manage(path->dentry, false);
                         if (ret < 0)
-                                return ret == -EISDIR ? 0 : ret;
+                                break;
                 }
 
                 /* Transit to a mounted filesystem. */
@@ -887,14 +891,19 @@ static int follow_managed(struct path *path, unsigned flags)
                 if (managed & DCACHE_NEED_AUTOMOUNT) {
                         ret = follow_automount(path, flags, &need_mntput);
                         if (ret < 0)
-                                return ret == -EISDIR ? 0 : ret;
+                                break;
                         continue;
                 }
 
                 /* We didn't change the current path point */
                 break;
         }
-        return 0;
+
+        if (need_mntput && path->mnt == mnt)
+                mntput(path->mnt);
+        if (ret == -EISDIR)
+                ret = 0;
+        return ret;
 }
 
 int follow_down_one(struct path *path)
@@ -1003,9 +1012,6 @@ failed:
  * Follow down to the covering mount currently visible to userspace.  At each
  * point, the filesystem owning that dentry may be queried as to whether the
  * caller is permitted to proceed or not.
- *
- * Care must be taken as namespace_sem may be held (indicated by mounting_here
- * being true).
  */
 int follow_down(struct path *path)
 {
@@ -2713,8 +2719,10 @@ static long do_unlinkat(int dfd, const char __user *pathname)
         error = PTR_ERR(dentry);
         if (!IS_ERR(dentry)) {
                 /* Why not before? Because we want correct error value */
+                if (nd.last.name[nd.last.len])
+                        goto slashes;
                 inode = dentry->d_inode;
-                if (nd.last.name[nd.last.len] || !inode)
+                if (!inode)
                         goto slashes;
                 ihold(inode);
                 error = mnt_want_write(nd.path.mnt);