From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 17 Jul 2025 14:54:34 +0000 (-0400)
Subject: ext4: do not BUG when INLINE_DATA_FL lacks system.data xattr
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=099b847ccc6c1ad2f805d13cfbcc83f5b6d4bc42;p=thirdparty%2Fkernel%2Flinux.git

ext4: do not BUG when INLINE_DATA_FL lacks system.data xattr

A syzbot fuzzed image triggered a BUG_ON in ext4_update_inline_data()
when an inode had the INLINE_DATA_FL flag set but was missing the
system.data extended attribute.

Since this can happen due to a maiciouly fuzzed file system, we
shouldn't BUG, but rather, report it as a corrupted file system.

Add similar replacements of BUG_ON with EXT4_ERROR_INODE() ii
ext4_create_inline_data() and ext4_inline_data_truncate().

Reported-by: syzbot+544248a761451c0df72f@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 640133adef380..1b094a4f38663 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -303,7 +303,11 @@ static int ext4_create_inline_data(handle_t *handle,
 	if (error)
 		goto out;
 
-	BUG_ON(!is.s.not_found);
+	if (!is.s.not_found) {
+		EXT4_ERROR_INODE(inode, "unexpected inline data xattr");
+		error = -EFSCORRUPTED;
+		goto out;
+	}
 
 	error = ext4_xattr_ibody_set(handle, inode, &i, &is);
 	if (error) {
@@ -354,7 +358,11 @@ static int ext4_update_inline_data(handle_t *handle, struct inode *inode,
 	if (error)
 		goto out;
 
-	BUG_ON(is.s.not_found);
+	if (is.s.not_found) {
+		EXT4_ERROR_INODE(inode, "missing inline data xattr");
+		error = -EFSCORRUPTED;
+		goto out;
+	}
 
 	len -= EXT4_MIN_INLINE_DATA_SIZE;
 	value = kzalloc(len, GFP_NOFS);
@@ -1869,7 +1877,12 @@ int ext4_inline_data_truncate(struct inode *inode, int *has_inline)
 			if ((err = ext4_xattr_ibody_find(inode, &i, &is)) != 0)
 				goto out_error;
 
-			BUG_ON(is.s.not_found);
+			if (is.s.not_found) {
+				EXT4_ERROR_INODE(inode,
+						 "missing inline data xattr");
+				err = -EFSCORRUPTED;
+				goto out_error;
+			}
 
 			value_len = le32_to_cpu(is.s.here->e_value_size);
 			value = kmalloc(value_len, GFP_NOFS);