From: Deepanshu Kartikey Date: Tue, 23 Sep 2025 13:32:45 +0000 (+0530) Subject: ext4: validate ea_ino and size in check_xattrs X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=44d2a72f4d64655f906ba47a5e108733f59e6f28;p=users%2Fhch%2Fmisc.git ext4: validate ea_ino and size in check_xattrs During xattr block validation, check_xattrs() processes xattr entries without validating that entries claiming to use EA inodes have non-zero sizes. Corrupted filesystems may contain xattr entries where e_value_size is zero but e_value_inum is non-zero, indicating invalid xattr data. Add validation in check_xattrs() to detect this corruption pattern early and return -EFSCORRUPTED, preventing invalid xattr entries from causing issues throughout the ext4 codebase. Cc: stable@kernel.org Suggested-by: Theodore Ts'o Reported-by: syzbot+4c9d23743a2409b80293@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=4c9d23743a2409b80293 Signed-off-by: Deepanshu Kartikey Signed-off-by: Theodore Ts'o Message-ID: <20250923133245.1091761-1-kartikey406@gmail.com> Signed-off-by: Theodore Ts'o --- diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 5b680deb1c9b..ce7253b3f549 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -251,6 +251,10 @@ check_xattrs(struct inode *inode, struct buffer_head *bh, err_str = "invalid ea_ino"; goto errout; } + if (ea_ino && !size) { + err_str = "invalid size in ea xattr"; + goto errout; + } if (size > EXT4_XATTR_SIZE_MAX) { err_str = "e_value size too large"; goto errout;