[PATCH RFC 3/7] pidfs: raise SB_I_NODEV and SB_I_NOEXEC

[Christian Brauner <brauner@kernel.org>]

Similar to commit 1ed95281c0c7 ("anon_inode: raise SB_I_NODEV and SB_I_NOEXEC"):
it shouldn't be possible to execute pidfds via
execveat(fd_anon_inode, "", NULL, NULL, AT_EMPTY_PATH)
so raise SB_I_NOEXEC so that no one gets any creative ideas.

Also raise SB_I_NODEV as we don't expect or support any devices on pidfs.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 fs/pidfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/pidfs.c b/fs/pidfs.c
index ca217bfe6e40..1343bfc60e3f 100644
--- a/fs/pidfs.c
+++ b/fs/pidfs.c
@@ -959,6 +959,8 @@ static int pidfs_init_fs_context(struct fs_context *fc)
 	if (!ctx)
 		return -ENOMEM;
 
+	fc->s_iflags |= SB_I_NOEXEC;
+	fc->s_iflags |= SB_I_NODEV;
 	ctx->ops = &pidfs_sops;
 	ctx->eops = &pidfs_export_operations;
 	ctx->dops = &pidfs_dentry_operations;

-- 
2.47.2