From: Eric Van Hensbergen ericvh@kernel.org

mainline inclusion from mainline-v6.9-rc1 commit 6630036b7c228f57c7893ee0403e92c2db2cd21d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9U997 CVE: CVE-2024-36923

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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 Conflicts: fs/9p/vfs_inode.c [Context changed since commit 80105ed2fd27 ("9p: Use netfslib read/write_iter") in v9fs_evict_inode] Signed-off-by: Long Li leo.lilong@huawei.com --- fs/9p/vfs_inode.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index 853c63b83681..c7c5631fe825 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -374,20 +374,24 @@ 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); + 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)