From: Eric Van Hensbergen ericvh@kernel.org
[ 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 ericvh@kernel.org (cherry picked from commit 1b4cb6e91f19b81217ad98142ee53a1ab25893fd) [Xiangyu: CVE-2024-36923 Minor conflict resolution due to missing 4eb31178 ] Signed-off-by: Xiangyu Chen xiangyu.chen@windriver.com --- fs/9p/vfs_inode.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index 8f287009545c..495631eba3a6 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -392,17 +392,20 @@ void v9fs_evict_inode(struct inode *inode) struct v9fs_inode *v9inode = V9FS_I(inode); __le32 version;
- truncate_inode_pages_final(&inode->i_data); - version = cpu_to_le32(v9inode->qid.version); - fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode, + if (!is_bad_inode(inode)) { + truncate_inode_pages_final(&inode->i_data); + version = cpu_to_le32(v9inode->qid.version); + fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode, &version); - clear_inode(inode); - filemap_fdatawrite(&inode->i_data); - - fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false); - /* clunk the fid stashed in writeback_fid */ - p9_fid_put(v9inode->writeback_fid); - v9inode->writeback_fid = NULL; + clear_inode(inode); + filemap_fdatawrite(&inode->i_data); + if (v9fs_inode_cookie(v9inode)) + fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false); + /* clunk the fid stashed in writeback_fid */ + p9_fid_put(v9inode->writeback_fid); + v9inode->writeback_fid = NULL; + } else + clear_inode(inode); }
static int v9fs_test_inode(struct inode *inode, void *data)