From 0a17567b4a85243ac1620886b75b3813acde41fc Mon Sep 17 00:00:00 2001 From: Jingbo Xu Date: Mon, 15 May 2023 18:39:41 +0800 Subject: [PATCH] erofs: fix null-ptr-deref caused by erofs_xattr_prefixes_init Fragments and dedupe share one feature bit, and thus packed inode may not exist when fragment feature bit (dedupe feature bit exactly) is set, e.g. when deduplication feature is in use while fragments feature is not. In this case, sbi->packed_inode could be NULL while fragments feature bit is set. Fix this by accessing packed inode only when it exists. Reported-by: syzbot+902d5a9373ae8f748a94@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=902d5a9373ae8f748a94 Reported-and-tested-by: syzbot+bbb353775d51424087f2@syzkaller.appspotmail.com Fixes: 9e382914617c ("erofs: add helpers to load long xattr name prefixes") Fixes: 6a318ccd7e08 ("erofs: enable long extended attribute name prefixes") Signed-off-by: Jingbo Xu Reviewed-by: Yue Hu Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20230515103941.129784-1-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang --- fs/erofs/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c index cd80499..bbfe7ce 100644 --- a/fs/erofs/xattr.c +++ b/fs/erofs/xattr.c @@ -675,7 +675,7 @@ int erofs_xattr_prefixes_init(struct super_block *sb) if (!pfs) return -ENOMEM; - if (erofs_sb_has_fragments(sbi)) + if (sbi->packed_inode) buf.inode = sbi->packed_inode; else erofs_init_metabuf(&buf, sb); -- 2.7.4