[PATCH 6.12 168/567] ext4: xattr: fix null pointer deref in ext4_raw_inode()

Greg Kroah-Hartman
2026-01-06T17:23:36Z

From: Karina Yankevich <k.yankevich@omp.ru>

commit b97cb7d6a051aa6ebd57906df0e26e9e36c26d14 upstream.

If ext4_get_inode_loc() fails (e.g. if it returns -EFSCORRUPTED),
iloc.bh will remain set to NULL. Since ext4_xattr_inode_dec_ref_all()
lacks error checking, this will lead to a null pointer dereference
in ext4_raw_inode(), called right after ext4_get_inode_loc().

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: c8e008b60492 ("ext4: ignore xattrs past end")
Cc: stable@kernel.org
Signed-off-by: Karina Yankevich <k.yankevich@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Message-ID: <20251022093253.3546296-1-k.yankevich@omp.ru>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ext4/xattr.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1174,7 +1174,11 @@ ext4_xattr_inode_dec_ref_all(handle_t *h
if (block_csum)
end = (void *)bh->b_data + bh->b_size;
else {
- ext4_get_inode_loc(parent, &iloc);
+ err = ext4_get_inode_loc(parent, &iloc);
+ if (err) {
+ EXT4_ERROR_INODE(parent, "parent inode loc (error %d)", err);
+ return;
+ }
end = (void *)ext4_raw_inode(&iloc) + EXT4_SB(parent->i_sb)->s_inode_size;
}