6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cen Zhang [ Upstream commit 8914a3330b72378136c2c02d6328a826f6abdad7 ] Patch series "ocfs2: validate xattr entry bounds", v7. This series validates OCFS2 xattr entry name/value bounds when xattr metadata is read and validated, before getxattr() or listxattr() can walk out-of-range entry arrays or offsets from corrupted metadata. This patch (of 2): ocfs2_validate_inode_block() verifies a dinode before OCFS2 users walk metadata from it, but inline xattr metadata is still checked only in operation-specific consumers. The existing ibody lookup helper validates inline header placement and entry count, but inode block validation does not reject entry name/value bounds. Add a flat xattr entry validator and call it from inode block validation for inline xattrs. Keep the operation paths on their existing header/count lookup checks; the full entry bounds check now runs when the inode block is validated at read time. Reject corrupted inline xattr metadata before ocfs2_xattr_ibody_get() or listxattr() can walk past the inline storage. Validation reproduced this kernel report: BUG: KASAN: use-after-free in ocfs2_xattr_find_entry+0x5a/0x170 Read of size 2 at addr ffff8881242a2000 by task python3/529 Call Trace: dump_stack_lvl+0x66/0xa0 print_report+0xce/0x630 kasan_report+0xe0/0x110 ocfs2_xattr_find_entry+0x5a/0x170 ocfs2_xattr_get_nolock+0x20a/0x820 ocfs2_xattr_get+0x10c/0x1e0 __vfs_getxattr+0xe2/0x130 vfs_getxattr+0x185/0x1b0 Link: https://lore.kernel.org/20260705025311.3429854-1-zzzccc427@gmail.com Link: https://lore.kernel.org/20260705025311.3429854-2-zzzccc427@gmail.com Fixes: cf1d6c763fbc ("ocfs2: Add extended attribute support") Signed-off-by: Cen Zhang Assisted-by: Codex:gpt-5.5 Reviewed-by: Joseph Qi Cc: Changwei Ge Cc: Heming Zhao Cc: Joel Becker Cc: Jun Piao Cc: Junxiao Bi Cc: Mark Fasheh Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- fs/ocfs2/inode.c | 4 ++ fs/ocfs2/xattr.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++ fs/ocfs2/xattr.h | 2 + 3 files changed, 124 insertions(+) diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c index b882092b351e0..01e33782f4f6e 100644 --- a/fs/ocfs2/inode.c +++ b/fs/ocfs2/inode.c @@ -1562,6 +1562,10 @@ int ocfs2_validate_inode_block(struct super_block *sb, goto bail; } + rc = ocfs2_validate_inode_xattr(sb, bh->b_blocknr, di); + if (rc) + goto bail; + if (le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL) { struct ocfs2_inline_data *data = &di->id2.i_data; diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index dc3d88a09d106..61ee0fb0c2a04 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -953,6 +953,124 @@ static int ocfs2_xattr_list_entries(struct inode *inode, return result; } +static int ocfs2_validate_xattr_entries_flat(struct super_block *sb, u64 blkno, + struct ocfs2_xattr_header *xh, + size_t region_size) +{ + u16 xattr_count = le16_to_cpu(xh->xh_count); + size_t entries_limit = region_size; + size_t nv_limit = region_size; + size_t max_entries; + int i; + + if (region_size < sizeof(*xh)) + return ocfs2_error(sb, + "Invalid xattr in block %llu: region size %zu is too small\n", + (unsigned long long)blkno, region_size); + + max_entries = (entries_limit - sizeof(*xh)) / + sizeof(struct ocfs2_xattr_entry); + + if (xattr_count > max_entries) + return ocfs2_error(sb, + "Invalid xattr in block %llu: entry count %u exceeds maximum %zu\n", + (unsigned long long)blkno, + xattr_count, max_entries); + + for (i = 0; i < xattr_count; i++) { + struct ocfs2_xattr_entry *xe = &xh->xh_entries[i]; + size_t name_offset = le16_to_cpu(xe->xe_name_offset); + size_t value_offset; + + if (name_offset > nv_limit || + xe->xe_name_len > nv_limit - name_offset) + return ocfs2_error(sb, + "Invalid xattr in block %llu: entry %d name is out of bounds\n", + (unsigned long long)blkno, i); + + value_offset = name_offset + OCFS2_XATTR_SIZE(xe->xe_name_len); + if (value_offset > nv_limit) + return ocfs2_error(sb, + "Invalid xattr in block %llu: entry %d value starts out of bounds\n", + (unsigned long long)blkno, i); + + if (ocfs2_xattr_is_local(xe)) { + if (le64_to_cpu(xe->xe_value_size) > + nv_limit - value_offset) + return ocfs2_error(sb, + "Invalid xattr in block %llu: entry %d value is out of bounds\n", + (unsigned long long)blkno, + i); + } else if (sizeof(struct ocfs2_xattr_value_root) > + nv_limit - value_offset) { + return ocfs2_error(sb, + "Invalid xattr in block %llu: entry %d value root is out of bounds\n", + (unsigned long long)blkno, i); + } + } + + return 0; +} + +static int ocfs2_xattr_ibody_lookup_header_raw(struct super_block *sb, + u64 blkno, + struct ocfs2_dinode *di, + struct ocfs2_xattr_header **header, + u16 *inline_size_ret) +{ + struct ocfs2_xattr_header *xh; + u16 xattr_count; + size_t max_entries; + u16 inline_size = le16_to_cpu(di->i_xattr_inline_size); + + if (inline_size > sb->s_blocksize || + inline_size < sizeof(struct ocfs2_xattr_header)) { + ocfs2_error(sb, + "Invalid inode %llu: xattr inline size %u\n", + (unsigned long long)blkno, inline_size); + return -EFSCORRUPTED; + } + + xh = (struct ocfs2_xattr_header *) + ((void *)di + sb->s_blocksize - inline_size); + + xattr_count = le16_to_cpu(xh->xh_count); + max_entries = (inline_size - sizeof(struct ocfs2_xattr_header)) / + sizeof(struct ocfs2_xattr_entry); + + if (xattr_count > max_entries) { + ocfs2_error(sb, + "xattr entry count %u exceeds maximum %zu in inode %llu\n", + xattr_count, max_entries, + (unsigned long long)blkno); + return -EFSCORRUPTED; + } + + *header = xh; + if (inline_size_ret) + *inline_size_ret = inline_size; + + return 0; +} + +int ocfs2_validate_inode_xattr(struct super_block *sb, u64 blkno, + struct ocfs2_dinode *di) +{ + struct ocfs2_xattr_header *xh; + u16 inline_size; + int ret; + + if (!(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_XATTR_FL)) + return 0; + + ret = ocfs2_xattr_ibody_lookup_header_raw(sb, blkno, di, &xh, + &inline_size); + if (ret) + return ret; + + return ocfs2_validate_xattr_entries_flat(sb, blkno, xh, inline_size); +} + int ocfs2_has_inline_xattr_value_outside(struct inode *inode, struct ocfs2_dinode *di) { diff --git a/fs/ocfs2/xattr.h b/fs/ocfs2/xattr.h index 016374e9a147e..2c4d895ed5ebf 100644 --- a/fs/ocfs2/xattr.h +++ b/fs/ocfs2/xattr.h @@ -43,6 +43,8 @@ int ocfs2_xattr_set_handle(handle_t *, struct inode *, struct buffer_head *, struct ocfs2_alloc_context *); int ocfs2_has_inline_xattr_value_outside(struct inode *inode, struct ocfs2_dinode *di); +int ocfs2_validate_inode_xattr(struct super_block *sb, u64 blkno, + struct ocfs2_dinode *di); int ocfs2_xattr_remove(struct inode *, struct buffer_head *); int ocfs2_init_security_get(struct inode *, struct inode *, const struct qstr *, -- 2.53.0