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([103.172.182.26]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-36132c8bd25sm1010534a91.3.2026.04.15.21.48.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2026 21:48:15 -0700 (PDT) From: gality369 X-Google-Original-From: gality369 To: mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com, r33s3n6@gmail.com, zzzccc427@gmail.com, gality369 Subject: [PATCH] ocfs2: reject inconsistent local xattr entries Date: Thu, 16 Apr 2026 12:48:06 +0800 Message-ID: <20260416044806.3007438-1-gality369@example.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit [BUG] A corrupt OCFS2 xattr entry can set OCFS2_XATTR_ENTRY_LOCAL while keeping xe_value_size larger than OCFS2_XATTR_INLINE_SIZE. Once that entry reaches namevalue_size_xe(), the filesystem trips over: kernel BUG at fs/ocfs2/xattr.c:231! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:namevalue_size_xe fs/ocfs2/xattr.c:231 [inline] RIP: 0010:ocfs2_xa_block_wipe_namevalue+0x2e4/0x330 fs/ocfs2/xattr.c:1638 Call Trace: ocfs2_xa_wipe_namevalue fs/ocfs2/xattr.c:1470 [inline] ocfs2_xa_remove_entry+0xae/0x1d0 fs/ocfs2/xattr.c:1941 ocfs2_xa_remove fs/ocfs2/xattr.c:2043 [inline] ocfs2_xa_set+0x11a8/0x30a0 fs/ocfs2/xattr.c:2247 ocfs2_xattr_ibody_set+0x302/0xc50 fs/ocfs2/xattr.c:2795 __ocfs2_xattr_set_handle+0x7e6/0xdb0 fs/ocfs2/xattr.c:3416 ocfs2_xattr_set+0x1447/0x2610 fs/ocfs2/xattr.c:3650 ocfs2_xattr_security_set+0x37/0x50 fs/ocfs2/xattr.c:7241 __vfs_removexattr+0x14d/0x1d0 fs/xattr.c:518 cap_inode_killpriv+0x29/0x50 security/commoncap.c:355 security_inode_killpriv+0x105/0x220 security/security.c:2724 setattr_prepare+0x147/0x8a0 fs/attr.c:219 ocfs2_setattr+0x504/0x1fd0 fs/ocfs2/file.c:1148 notify_change+0x4b5/0x1030 fs/attr.c:546 do_truncate+0x1d2/0x230 fs/open.c:68 handle_truncate fs/namei.c:3596 [inline] do_open fs/namei.c:3979 [inline] path_openat+0x260f/0x2ce0 fs/namei.c:4134 do_filp_open+0x1f6/0x430 fs/namei.c:4161 do_sys_openat2+0x117/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] ... [CAUSE] namevalue_size_xe() assumes on-disk xattr entries keep the local flag and value size consistent, but OCFS2 does not reject an entry that claims local storage for a value larger than the inline limit before handing that entry to namevalue_size_xe(). The exact-match lookup path can return such an entry through xs->here, and bucket defragmentation and splitting can also walk the corrupt entry directly while reorganizing metadata. [FIX] Add a small validator for the local/value_size invariant and call it in the paths that feed disk entries to namevalue_size_xe(): exact-match lookup, bucket lookup results, bucket defragmentation, and bucket splitting. Corrupt metadata is now reported with ocfs2_error() and -EFSCORRUPTED instead of crashing the kernel with BUG_ON(). Signed-off-by: gality369 --- No Fixes tag was added because this is more like a defensive check that is long overdue, not a regression that can be clearly attributed to a specific introduction commit. --- diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 86cfd4c2adf9..63b1e55b242f 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -237,6 +237,23 @@ static int namevalue_size_xe(struct ocfs2_xattr_entry *xe) return namevalue_size(xe->xe_name_len, value_len); } +static int ocfs2_validate_xattr_entry(struct inode *inode, + struct ocfs2_xattr_entry *xe) +{ + u64 value_len = le64_to_cpu(xe->xe_value_size); + + if (value_len > OCFS2_XATTR_INLINE_SIZE && + ocfs2_xattr_is_local(xe)) { + ocfs2_error(inode->i_sb, + "Inode %llu has corrupt xattr entry: local value_size %llu\n", + (unsigned long long)OCFS2_I(inode)->ip_blkno, + value_len); + return -EFSCORRUPTED; + } + + return 0; +} + static int ocfs2_xattr_bucket_get_name_value(struct super_block *sb, struct ocfs2_xattr_header *xh, @@ -1099,6 +1116,7 @@ static int ocfs2_xattr_find_entry(struct inode *inode, int name_index, struct ocfs2_xattr_entry *entry; size_t name_len; int i, name_offset, cmp = 1; + int ret; if (name == NULL) return -EINVAL; @@ -1121,6 +1139,11 @@ static int ocfs2_xattr_find_entry(struct inode *inode, int name_index, return -EFSCORRUPTED; } cmp = memcmp(name, (xs->base + name_offset), name_len); + if (!cmp) { + ret = ocfs2_validate_xattr_entry(inode, entry); + if (ret) + return ret; + } } if (cmp == 0) break; @@ -3823,6 +3846,9 @@ static int ocfs2_find_xe_in_bucket(struct inode *inode, xe_name = bucket_block(bucket, block_off) + new_offset; if (!memcmp(name, xe_name, name_len)) { + ret = ocfs2_validate_xattr_entry(inode, xe); + if (ret) + break; *xe_index = i; *found = 1; ret = 0; @@ -4463,6 +4489,10 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode, xe = xh->xh_entries; end = OCFS2_XATTR_BUCKET_SIZE; for (i = 0; i < le16_to_cpu(xh->xh_count); i++, xe++) { + ret = ocfs2_validate_xattr_entry(inode, xe); + if (ret) + goto out; + offset = le16_to_cpu(xe->xe_name_offset); len = namevalue_size_xe(xe); @@ -4745,6 +4775,10 @@ static int ocfs2_divide_xattr_bucket(struct inode *inode, name_value_len = 0; for (i = 0; i < start; i++) { xe = &xh->xh_entries[i]; + ret = ocfs2_validate_xattr_entry(inode, xe); + if (ret) + goto out; + name_value_len += namevalue_size_xe(xe); if (le16_to_cpu(xe->xe_name_offset) < name_offset) name_offset = le16_to_cpu(xe->xe_name_offset); -- 2.43.0