5.15-stable review patch. If anyone has any objections, please let me know.
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From: Miklos Szeredi mszeredi@redhat.com
[ Upstream commit 68ca1b49e430f6534d0774a94147a823e3b8b26e ]
The root inode has a fixed nodeid and generation (1, 0).
Prior to the commit 15db16837a35 ("fuse: fix illegal access to inode with reused nodeid") generation number on lookup was ignored. After this commit lookup with the wrong generation number resulted in the inode being unhashed. This is correct for non-root inodes, but replacing the root inode is wrong and results in weird behavior.
Fix by reverting to the old behavior if ignoring the generation for the root inode, but issuing a warning in dmesg.
Reported-by: Antonio SJ Musumeci trapexit@spawn.link Closes: https://lore.kernel.org/all/CAOQ4uxhek5ytdN8Yz2tNEOg5ea4NkBb4nk0FGPjPk_9nz-V... Fixes: 15db16837a35 ("fuse: fix illegal access to inode with reused nodeid") Cc: stable@vger.kernel.org # v5.14 Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/fuse/dir.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 4ea52906ae150..44d1c8cc58a42 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -390,6 +390,10 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name goto out_put_forget; if (fuse_invalid_attr(&outarg->attr)) goto out_put_forget; + if (outarg->nodeid == FUSE_ROOT_ID && outarg->generation != 0) { + pr_warn_once("root generation should be zero\n"); + outarg->generation = 0; + }
*inode = fuse_iget(sb, outarg->nodeid, outarg->generation, &outarg->attr, entry_attr_timeout(outarg),