From a53411e805e02d813b2f2fd2c9d6eaca1d37fb08 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 8 Jan 2024 17:22:36 +0000 Subject: [PATCH] afs: Hide silly-rename files from userspace [ Upstream commit 57e9d49c54528c49b8bffe6d99d782ea051ea534 ] There appears to be a race between silly-rename files being created/removed and various userspace tools iterating over the contents of a directory, leading to such errors as: find: './kernel/.tmp_cpio_dir/include/dt-bindings/reset/.__afs2080': No such file or directory tar: ./include/linux/greybus/.__afs3C95: File removed before we read it when building a kernel. Fix afs_readdir() so that it doesn't return .__afsXXXX silly-rename files to userspace. This doesn't stop them being looked up directly by name as we need to be able to look them up from within the kernel as part of the silly-rename algorithm. Fixes: 79ddbfa500b3 ("afs: Implement sillyrename for unlink and rename") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: Sasha Levin --- fs/afs/dir.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 5219182e52e1..2df2e9ee130d 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -474,6 +474,14 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode, continue; } + /* Don't expose silly rename entries to userspace. */ + if (nlen > 6 && + dire->u.name[0] == '.' && + ctx->actor != afs_lookup_filldir && + ctx->actor != afs_lookup_one_filldir && + memcmp(dire->u.name, ".__afs", 6) == 0) + continue; + /* found the next entry */ if (!dir_emit(ctx, dire->u.name, nlen, ntohl(dire->u.vnode),