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authorMiklos Szeredi <mszeredi@redhat.com>2020-12-10 15:33:14 +0100
committerMiklos Szeredi <mszeredi@redhat.com>2020-12-10 15:33:14 +0100
commit5d069dbe8aaf2a197142558b6fb2978189ba3454 (patch)
tree4c9ddb84e8fde7b3120e76c733fca542a5ff7ca2 /fs/fuse/readdir.c
parent9d769e6aa2524e1762e3b8681e0ed78f8acf6cad (diff)
fuse: fix bad inode
Jan Kara's analysis of the syzbot report (edited): The reproducer opens a directory on FUSE filesystem, it then attaches dnotify mark to the open directory. After that a fuse_do_getattr() call finds that attributes returned by the server are inconsistent, and calls make_bad_inode() which, among other things does: inode->i_mode = S_IFREG; This then confuses dnotify which doesn't tear down its structures properly and eventually crashes. Avoid calling make_bad_inode() on a live inode: switch to a private flag on the fuse inode. Also add the test to ops which the bad_inode_ops would have caught. This bug goes back to the initial merge of fuse in 2.6.14... Reported-by: syzbot+f427adf9324b92652ccc@syzkaller.appspotmail.com Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org>
Diffstat (limited to 'fs/fuse/readdir.c')
-rw-r--r--fs/fuse/readdir.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c
index 3b5e91045871..3441ffa740f3 100644
--- a/fs/fuse/readdir.c
+++ b/fs/fuse/readdir.c
@@ -207,7 +207,7 @@ retry:
dput(dentry);
goto retry;
}
- if (is_bad_inode(inode)) {
+ if (fuse_is_bad(inode)) {
dput(dentry);
return -EIO;
}
@@ -568,7 +568,7 @@ int fuse_readdir(struct file *file, struct dir_context *ctx)
struct inode *inode = file_inode(file);
int err;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;
mutex_lock(&ff->readdir.lock);