On Mon 07-04-25 11:54:19, Christian Brauner wrote:
It isn't possible to execute anoymous inodes because they cannot be
^^ anonymous
opened in any way after they have been created. This includes execution:
execveat(fd_anon_inode, "", NULL, NULL, AT_EMPTY_PATH)
Anonymous inodes have inode->f_op set to no_open_fops which sets no_open() which returns ENXIO. That means any call to do_dentry_open() which is the endpoint of the do_open_execat() will fail. There's no chance to execute an anonymous inode. Unless a given subsystem overrides it ofc.
Howerver, we should still harden this and raise SB_I_NODEV and
^^^ However
SB_I_NOEXEC on the superblock itself so that no one gets any creative ideas.
;)
Feel free to add:
Reviewed-by: Jan Kara jack@suse.cz
Honza
Cc: stable@vger.kernel.org # all LTS kernels Signed-off-by: Christian Brauner brauner@kernel.org
fs/anon_inodes.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index cb51a90bece0..e51e7d88980a 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -86,6 +86,8 @@ static int anon_inodefs_init_fs_context(struct fs_context *fc) struct pseudo_fs_context *ctx = init_pseudo(fc, ANON_INODE_FS_MAGIC); if (!ctx) return -ENOMEM;
- fc->s_iflags |= SB_I_NOEXEC;
- fc->s_iflags |= SB_I_NODEV; ctx->dops = &anon_inodefs_dentry_operations; return 0;
}
-- 2.47.2