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authorZhengYuan Huang <gality369@gmail.com>2026-05-08 16:59:10 +0800
committerAndrew Morton <akpm@linux-foundation.org>2026-05-28 21:24:47 -0700
commitbef1006da49c91e8e154223d3005829a394f8f78 (patch)
tree6610d14de3865dd9f3ba55672dbedb4564a2aa2b /fs
parentc0438198c28b1d22c272751af5e717c11d9fa8dd (diff)
downloadlinux-next-history-bef1006da49c91e8e154223d3005829a394f8f78.tar.gz
ocfs2: validate inline xattr header before ibody lookups
Patch series "ocfs2: validate inline xattr header consumers". Corrupt i_xattr_inline_size can move the computed inode-body xattr header outside the dinode block. Several OCFS2 paths then trust xh_count or xattr entry geometry from that unchecked header. The reported KASAN splat hits the ibody lookup path: BUG: KASAN: use-after-free in ocfs2_xattr_find_entry+0x37b/0x3a0 ocfs2_xattr_ibody_get() ocfs2_xattr_get_nolock() ocfs2_calc_xattr_init() The same unchecked header derivation also exists in the outside-value probe, ibody remove, inline refcount attach, and inline reflink paths. This series factors the existing ibody list validation into a shared helper and then converts the remaining inline-header consumers one at a time. Patch layout: 1. validate ibody get/find and reuse the helper in ibody list 2. validate the outside-value probe 3. validate ibody remove 4. validate inline refcount attach 5. validate inline reflink This patch (of 5): [BUG] mknodat() can read past the end of a dinode block when ACL inheritance walks a corrupted inode-body xattr header. Another report shows the same unchecked lookup later faulting in the VFS open path after create returns a garbage status. KASAN: use-after-free in ocfs2_xattr_find_entry+0x37b/0x3a0 fs/ocfs2/xattr.c:1078 Read of size 2 at addr ffff88801c520300 by task syz.0.10/360 Trace: ... ocfs2_xattr_find_entry+0x37b/0x3a0 fs/ocfs2/xattr.c:1078 ocfs2_xattr_ibody_get fs/ocfs2/xattr.c:1178 [inline] ocfs2_xattr_get_nolock+0x2ee/0x1110 fs/ocfs2/xattr.c:1309 ocfs2_calc_xattr_init+0x716/0xac0 fs/ocfs2/xattr.c:628 ocfs2_mknod+0x935/0x2400 fs/ocfs2/namei.c:333 ocfs2_create+0x158/0x390 fs/ocfs2/namei.c:676 vfs_create fs/namei.c:3493 [inline] vfs_create+0x445/0x6f0 fs/namei.c:3477 do_mknodat+0x2d8/0x5e0 fs/namei.c:4372 __do_sys_mknodat fs/namei.c:4400 [inline] __se_sys_mknodat fs/namei.c:4397 [inline] __x64_sys_mknodat+0xb6/0xf0 fs/namei.c:4397 ... Another report: BUG: unable to handle page fault for address: fffffbfff3e40ec0 RIP: 0010:__d_entry_type include/linux/dcache.h:414 [inline] RIP: 0010:d_can_lookup include/linux/dcache.h:429 [inline] RIP: 0010:d_is_dir include/linux/dcache.h:439 [inline] RIP: 0010:path_openat+0xe2f/0x2ce0 fs/namei.c:4134 Trace: ... do_filp_open+0x1f6/0x430 fs/namei.c:4161 do_sys_openat2+0x117/0x1c0 fs/open.c:1437 __x64_sys_openat+0x15b/0x220 fs/open.c:1463 ... [CAUSE] ocfs2_xattr_ibody_list() already validates the inline xattr size and entry count, but ocfs2_xattr_ibody_get() and ocfs2_xattr_ibody_find() still derive the inline header directly from di->i_xattr_inline_size and then trust xh_count. A corrupted inline size or entry count can therefore move the computed header outside the dinode block before get/find start walking it. That can either make ocfs2_xattr_find_entry() dereference xs->header->xh_count outside the block or make ocfs2_xattr_get_nolock() bubble a garbage status back through ocfs2_calc_xattr_init() into the create/open path. [FIX] Factor the existing ibody header geometry checks into a shared helper. Use it in ocfs2_xattr_ibody_get() and ocfs2_xattr_ibody_find(), and have ocfs2_xattr_ibody_list() reuse the same helper instead of open-coding the validation. Reject corrupt ibody metadata with -EFSCORRUPTED before the lookup path can walk bogus xattr geometry or return a garbage status. Link: https://lore.kernel.org/20260508085914.61647-1-gality369@gmail.com Link: https://lore.kernel.org/20260508085914.61647-2-gality369@gmail.com Signed-off-by: ZhengYuan Huang <gality369@gmail.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Jia-Ju Bai <baijiaju1990@gmail.com> Cc: Zixuan Fu <r33s3n6@gmail.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Jun Piao <piaojun@huawei.com> Cc: Heming Zhao <heming.zhao@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ocfs2/xattr.c82
1 files changed, 47 insertions, 35 deletions
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 86cfd4c2adf92..3a5a17cdcf7eb 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -950,6 +950,41 @@ static int ocfs2_xattr_list_entries(struct inode *inode,
return result;
}
+static int ocfs2_xattr_ibody_lookup_header(struct inode *inode,
+ struct ocfs2_dinode *di,
+ struct ocfs2_xattr_header **header)
+{
+ u16 xattr_count;
+ size_t max_entries;
+ u16 inline_size = le16_to_cpu(di->i_xattr_inline_size);
+
+ if (inline_size > inode->i_sb->s_blocksize ||
+ inline_size < sizeof(struct ocfs2_xattr_header)) {
+ ocfs2_error(inode->i_sb,
+ "Invalid xattr inline size %u in inode %llu\n",
+ inline_size,
+ (unsigned long long)OCFS2_I(inode)->ip_blkno);
+ return -EFSCORRUPTED;
+ }
+
+ *header = (struct ocfs2_xattr_header *)
+ ((void *)di + inode->i_sb->s_blocksize - inline_size);
+
+ xattr_count = le16_to_cpu((*header)->xh_count);
+ max_entries = (inline_size - sizeof(struct ocfs2_xattr_header)) /
+ sizeof(struct ocfs2_xattr_entry);
+
+ if (xattr_count > max_entries) {
+ ocfs2_error(inode->i_sb,
+ "xattr entry count %u exceeds maximum %zu in inode %llu\n",
+ xattr_count, max_entries,
+ (unsigned long long)OCFS2_I(inode)->ip_blkno);
+ return -EFSCORRUPTED;
+ }
+
+ return 0;
+}
+
int ocfs2_has_inline_xattr_value_outside(struct inode *inode,
struct ocfs2_dinode *di)
{
@@ -975,39 +1010,13 @@ static int ocfs2_xattr_ibody_list(struct inode *inode,
struct ocfs2_xattr_header *header = NULL;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
int ret = 0;
- u16 xattr_count;
- size_t max_entries;
- u16 inline_size;
if (!(oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL))
return ret;
- inline_size = le16_to_cpu(di->i_xattr_inline_size);
-
- /* Validate inline size is reasonable */
- if (inline_size > inode->i_sb->s_blocksize ||
- inline_size < sizeof(struct ocfs2_xattr_header)) {
- ocfs2_error(inode->i_sb,
- "Invalid xattr inline size %u in inode %llu\n",
- inline_size,
- (unsigned long long)OCFS2_I(inode)->ip_blkno);
- return -EFSCORRUPTED;
- }
-
- header = (struct ocfs2_xattr_header *)
- ((void *)di + inode->i_sb->s_blocksize - inline_size);
-
- xattr_count = le16_to_cpu(header->xh_count);
- max_entries = (inline_size - sizeof(struct ocfs2_xattr_header)) /
- sizeof(struct ocfs2_xattr_entry);
-
- if (xattr_count > max_entries) {
- ocfs2_error(inode->i_sb,
- "xattr entry count %u exceeds maximum %zu in inode %llu\n",
- xattr_count, max_entries,
- (unsigned long long)OCFS2_I(inode)->ip_blkno);
- return -EFSCORRUPTED;
- }
+ ret = ocfs2_xattr_ibody_lookup_header(inode, di, &header);
+ if (ret)
+ return ret;
ret = ocfs2_xattr_list_entries(inode, header, buffer, buffer_size);
@@ -1200,8 +1209,9 @@ static int ocfs2_xattr_ibody_get(struct inode *inode,
return -ENODATA;
xs->end = (void *)di + inode->i_sb->s_blocksize;
- xs->header = (struct ocfs2_xattr_header *)
- (xs->end - le16_to_cpu(di->i_xattr_inline_size));
+ ret = ocfs2_xattr_ibody_lookup_header(inode, di, &xs->header);
+ if (ret)
+ return ret;
xs->base = (void *)xs->header;
xs->here = xs->header->xh_entries;
@@ -2726,12 +2736,14 @@ static int ocfs2_xattr_ibody_find(struct inode *inode,
xs->xattr_bh = xs->inode_bh;
xs->end = (void *)di + inode->i_sb->s_blocksize;
- if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL)
- xs->header = (struct ocfs2_xattr_header *)
- (xs->end - le16_to_cpu(di->i_xattr_inline_size));
- else
+ if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL) {
+ ret = ocfs2_xattr_ibody_lookup_header(inode, di, &xs->header);
+ if (ret)
+ return ret;
+ } else {
xs->header = (struct ocfs2_xattr_header *)
(xs->end - OCFS2_SB(inode->i_sb)->s_xattr_inline_size);
+ }
xs->base = (void *)xs->header;
xs->here = xs->header->xh_entries;
generated by cgit 1.3-korg (git 2.53.0) at 2026-06-01 04:05:25 +0000