Merging upstream version 6.10.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 24 insertions, 11 deletions

diff --git a/fs/namei.c b/fs/namei.c
index c5b2a25be7..1e05a0f3f0 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2422,6 +2422,14 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
 		if (!f.file)
 			return ERR_PTR(-EBADF);
 
+		if (flags & LOOKUP_LINKAT_EMPTY) {
+			if (f.file->f_cred != current_cred() &&
+			    !ns_capable(f.file->f_cred->user_ns, CAP_DAC_READ_SEARCH)) {
+				fdput(f);
+				return ERR_PTR(-ENOENT);
+			}
+		}
+
 		dentry = f.file->f_path.dentry;
 
 		if (*s && unlikely(!d_can_lookup(dentry))) {
@@ -3564,8 +3572,12 @@ static const char *open_last_lookups(struct nameidata *nd,
 	else
 		inode_lock_shared(dir->d_inode);
 	dentry = lookup_open(nd, file, op, got_write);
-	if (!IS_ERR(dentry) && (file->f_mode & FMODE_CREATED))
-		fsnotify_create(dir->d_inode, dentry);
+	if (!IS_ERR(dentry)) {
+		if (file->f_mode & FMODE_CREATED)
+			fsnotify_create(dir->d_inode, dentry);
+		if (file->f_mode & FMODE_OPENED)
+			fsnotify_open(file);
+	}
 	if (open_flag & O_CREAT)
 		inode_unlock(dir->d_inode);
 	else
@@ -3668,9 +3680,9 @@ static int do_open(struct nameidata *nd,
  * On non-idmapped mounts or if permission checking is to be performed on the
  * raw inode simply pass @nop_mnt_idmap.
  */
-static int vfs_tmpfile(struct mnt_idmap *idmap,
-		       const struct path *parentpath,
-		       struct file *file, umode_t mode)
+int vfs_tmpfile(struct mnt_idmap *idmap,
+		const struct path *parentpath,
+		struct file *file, umode_t mode)
 {
 	struct dentry *child;
 	struct inode *dir = d_inode(parentpath->dentry);
@@ -3692,6 +3704,8 @@ static int vfs_tmpfile(struct mnt_idmap *idmap,
 	mode = vfs_prepare_mode(idmap, dir, mode, mode, mode);
 	error = dir->i_op->tmpfile(idmap, dir, file, mode);
 	dput(child);
+	if (file->f_mode & FMODE_OPENED)
+		fsnotify_open(file);
 	if (error)
 		return error;
 	/* Don't check for other permissions, the inode was just created */
@@ -4641,14 +4655,13 @@ int do_linkat(int olddfd, struct filename *old, int newdfd,
 		goto out_putnames;
 	}
 	/*
-	 * To use null names we require CAP_DAC_READ_SEARCH
+	 * To use null names we require CAP_DAC_READ_SEARCH or
+	 * that the open-time creds of the dfd matches current.
 	 * This ensures that not everyone will be able to create
-	 * handlink using the passed filedescriptor.
+	 * a hardlink using the passed file descriptor.
 	 */
-	if (flags & AT_EMPTY_PATH && !capable(CAP_DAC_READ_SEARCH)) {
-		error = -ENOENT;
-		goto out_putnames;
-	}
+	if (flags & AT_EMPTY_PATH)
+		how |= LOOKUP_LINKAT_EMPTY;
 
 	if (flags & AT_SYMLINK_FOLLOW)
 		how |= LOOKUP_FOLLOW;