From 0720a6f5d10b7cf38eb4430db837c0c2ea20a8db Mon Sep 17 00:00:00 2001 From: Zhang Enpei Date: Wed, 2 Jul 2025 12:13:16 +0800 Subject: [PATCH] fs/9p: fix uninitialized values during inode evict commit 3a741b80b3457f079cf637e47800fb7bf8038ad6 upstream. [ Upstream commit 6630036b7c228f57c7893ee0403e92c2db2cd21d ] If an iget fails due to not being able to retrieve information from the server then the inode structure is only partially initialized. When the inode gets evicted, references to uninitialized structures (like fscache cookies) were being made. This patch checks for a bad_inode before doing anything other than clearing the inode from the cache. Since the inode is bad, it shouldn't have any state associated with it that needs to be written back (and there really isn't a way to complete those anyways). Reported-by: syzbot+eb83fe1cce5833cd66a0@syzkaller.appspotmail.com Signed-off-by: Eric Van Hensbergen Signed-off-by: Sasha Levin [Xiangyu: CVE-2024-36923 Minor conflict resolution ] Signed-off-by: Xiangyu Chen Signed-off-by: Greg Kroah-Hartman Fixes: CVE-2024-36923 Signed-off-by: Enpei Zhang Signed-off-by: Wenya Zhang Reviewed-by: Xuexin Jiang --- fs/9p/vfs_inode.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index ea695c4a7a3f..a183482a2ac4 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -371,20 +371,23 @@ void v9fs_evict_inode(struct inode *inode) struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode); __le32 __maybe_unused version; - truncate_inode_pages_final(&inode->i_data); + if (!is_bad_inode(inode)) { + truncate_inode_pages_final(&inode->i_data); #ifdef CONFIG_9P_FSCACHE - version = cpu_to_le32(v9inode->qid.version); - fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode, + version = cpu_to_le32(v9inode->qid.version); + fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode, &version); #endif - - clear_inode(inode); - filemap_fdatawrite(&inode->i_data); + clear_inode(inode); + filemap_fdatawrite(&inode->i_data); #ifdef CONFIG_9P_FSCACHE - fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false); + if (v9fs_inode_cookie(v9inode)) + fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false); #endif + } else + clear_inode(inode); } static int v9fs_test_inode(struct inode *inode, void *data) -- Gitee