6.6-stable review patch. If anyone has any objections, please let me know.
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From: Deepanshu Kartikey kartikey406@gmail.com
commit 44d2a72f4d64655f906ba47a5e108733f59e6f28 upstream.
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 tytso@mit.edu Reported-by: syzbot+4c9d23743a2409b80293@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=4c9d23743a2409b80293 Signed-off-by: Deepanshu Kartikey kartikey406@gmail.com Signed-off-by: Theodore Ts'o tytso@mit.edu Message-ID: 20250923133245.1091761-1-kartikey406@gmail.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/xattr.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -251,6 +251,10 @@ check_xattrs(struct inode *inode, struct 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;