kernel/git/stable/linux.git/fs/udf, branch linux-6.6.y

UDF symlink pathComponent header OOB read

2026-09-14T11:29:14+00:00

[ Upstream commit d23eb7380d1594cda31a5dc8487dd2a5c8def8c7 ] udf_symlink_filler() can enter udf_pc_to_char() with a partial pathComponent header. Validate that enough input remains for a complete pathComponent header before accessing it. Reject malformed symlink data that would otherwise make udf_pc_to_char() perform an out-of-bounds read. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: David Lee Assisted-by: Codex:gpt-5.5 Link: https://patch.msgid.link/20260717104722.41446-1-david.lee@trailofbits.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin

udf: Mark LVID buffer as uptodate before marking it dirty

2026-09-14T11:29:07+00:00

[ Upstream commit fb0601134c7e51728bd098abc6909315de1e5d86 ] When an I/O error occurs while writing the Logical Volume Integrity Descriptor (LVID) buffer to the block device, the block layer's completion handler (`end_buffer_write_sync()`) clears the `BH_Uptodate` flag on the buffer. However, the buffer still contains valid LVID data in memory. If the filesystem is subsequently remounted read-write or synced, `udf_open_lvid()` or `udf_sync_fs()` will modify the LVID buffer and call `mark_buffer_dirty()`. This triggers a spurious `WARN_ON_ONCE(!buffer_uptodate(bh))` warning in `mark_buffer_dirty()` because the buffer is not marked uptodate, even though its in-memory contents are valid and are about to be overwritten. To prevent this spurious warning, unconditionally set the `BH_Uptodate` flag before calling `mark_buffer_dirty()` in `udf_open_lvid()` and `udf_sync_fs()`. This acknowledges that the in-memory buffer is valid and matches the workaround previously applied to `udf_close_lvid()` in commit 853a0c25baf9 ("udf: Mark LVID buffer as uptodate before marking it dirty"). Extending this workaround ensures consistent behavior across all LVID updates. Buffer I/O error on dev loop0, logical block 128, lost sync page write ------------[ cut here ]------------ !buffer_uptodate(bh) WARNING: fs/buffer.c:1087 at mark_buffer_dirty+0x299/0x410 fs/buffer.c:1087 ... Call Trace: udf_open_lvid+0x369/0x5b0 fs/udf/super.c:2078 udf_reconfigure+0x336/0x540 fs/udf/super.c:679 reconfigure_super+0x232/0x8f0 fs/super.c:1080 vfs_cmd_reconfigure fs/fsopen.c:268 [inline] vfs_fsconfig_locked+0x171/0x320 fs/fsopen.c:297 __do_sys_fsconfig fs/fsopen.c:463 [inline] __se_sys_fsconfig+0x6b9/0x810 fs/fsopen.c:350 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 Fixes: 853a0c25baf9 ("udf: Mark LVID buffer as uptodate before marking it dirty") Assisted-by: Gemini:gemini-3.1-pro-preview Gemini:gemini-3-flash-preview syzbot Reported-by: syzbot+0306b38d9ed6ef71467d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0306b38d9ed6ef71467d Link: https://syzkaller.appspot.com/ai_job?id=05f8e20f-f080-4c7f-a206-08dbc15cb4a1 Signed-off-by: Aleksandr Nogikh Link: https://patch.msgid.link/6ffb2ca8-e22f-4fd6-9f37-7202ec0878bd@mail.kernel.org Signed-off-by: Jan Kara Signed-off-by: Sasha Levin

udf: Fix i_lenExtents truncation on 32-bit kernels

2026-09-14T11:28:37+00:00

commit a5a5ed23b1340ff0f32a14a7ca8585f7c4e9b2e2 upstream. In udf_do_extend_file() the total extent length is rounded up to a block boundary with: iinfo->i_lenExtents = (iinfo->i_lenExtents + sb->s_blocksize - 1) & ~(sb->s_blocksize - 1); i_lenExtents is a __u64, but sb->s_blocksize is unsigned long. On 32-bit kernels unsigned long is 32-bit, so ~(sb->s_blocksize - 1) is a 32-bit value (e.g. 0xfffff800 for a 2 KiB block) that is zero-extended in the AND, clearing the upper 32 bits of i_lenExtents. For UDF files whose total extent length exceeds 4 GiB this truncates i_lenExtents when the file is extended, corrupting the tracked extent length. Cast the block size to 64-bit before forming the mask. 64-bit kernels are unaffected. Fixes: 48d6d8ff7dca ("udf: cache struct udf_inode_info") Cc: stable@vger.kernel.org Signed-off-by: Zhan Xusheng Link: https://patch.msgid.link/20260722082425.213311-1-zhanxusheng@xiaomi.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

udf: reject VAT indexes equal to the entry count

2026-09-14T11:28:25+00:00

commit cac0cb07f29ccfb373fd4a36c81e908ef3ce608c upstream. UDF 1.50 virtual partition mapping uses the VAT as an array of physical block mappings. s_num_entries stores the number of entries in that array, not the highest valid index. The valid VAT indexes are therefore below s_num_entries. udf_get_pblock_virt15() currently rejects only indexes greater than s_num_entries. A crafted image can request index s_num_entries, pass the bounds check, and make the kernel read one entry past the allocated VAT table. Change the check to reject block >= s_num_entries, so the count is handled as an exclusive upper bound. A crafted UDF image reproduced this on origin/master commit 0e35b9b6ec0ffcc5e23cbdec09f5c622ad532b53 with a KASAN slab-out-of-bounds report in udf_get_pblock_virt15(). Trail of Bits has a reproducer that triggers kernel panic demonstrating the bug, and can share it if needed. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: David Lee Assisted-by: Codex:gpt-5.5 Link: https://patch.msgid.link/20260708101712.1706564-1-david.lee@trailofbits.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

udf: validate sparing table length as an entry count, not a byte count

2026-07-24T14:02:51+00:00

commit 3ec997bd5508e9b25210b5bbec89031629cdb093 upstream. udf_load_sparable_map() accepts a sparing table when sizeof(*st) + le16_to_cpu(st->reallocationTableLen) > sb->s_blocksize is false, i.e. it treats reallocationTableLen as a number of BYTES that must fit in the block. But the table is walked as an array of 8-byte sparingEntry elements: for (i = 0; i < le16_to_cpu(st->reallocationTableLen); i++) { struct sparingEntry *entry = &st->mapEntry[i]; ... entry->origLocation ... } in udf_get_pblock_spar15() and udf_relocate_blocks(). A reallocationTableLen of N therefore passes the check whenever sizeof(*st) + N <= blocksize, yet the consumers index sizeof(*st) + N * sizeof(struct sparingEntry) bytes -- up to ~8x the block. On a crafted UDF image this is an out-of-bounds read in udf_get_pblock_spar15(); udf_relocate_blocks() additionally feeds the same length to udf_update_tag(), whose crc_itu_t() reads far past the block, and its memmove() through st->mapEntry[] is an out-of-bounds write. Validate reallocationTableLen as the entry count it is, with struct_size(). Fixes: 1df2ae31c724 ("udf: Fortify loading of sparing table") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Link: https://patch.msgid.link/20260612-b4-disp-91780c4e-v1-1-f15112ff6882@proton.me Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

udf: validate VAT header length against the VAT inode size

2026-07-24T14:02:51+00:00

commit d8202786b3d75125c84ebc4de6d946f92fde0ee8 upstream. udf_load_vat() takes the virtual partition's start offset straight from the on-disk VAT 2.0 header without checking it against the VAT inode size: map->s_type_specific.s_virtual.s_start_offset = le16_to_cpu(vat20->lengthHeader); map->s_type_specific.s_virtual.s_num_entries = (sbi->s_vat_inode->i_size - map->s_type_specific.s_virtual.s_start_offset) >> 2; lengthHeader is a fully attacker-controlled 16-bit value. If it exceeds the VAT inode size, the s_num_entries subtraction underflows to a huge count, which defeats the "block > s_num_entries" bound in udf_get_pblock_virt15(); and on the ICB-inline path that function reads ((__le32 *)(iinfo->i_data + s_start_offset))[block] so a large s_start_offset indexes past the inode's in-ICB data. Mounting a crafted UDF image with a virtual (VAT) partition then triggers an out-of-bounds read. Reject a VAT whose header length does not leave room for at least one entry within the VAT inode. Fixes: fa5e08156335 ("udf: Handle VAT packed inside inode properly") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Link: https://patch.msgid.link/20260612-b4-disp-9a2317ee-v1-1-fefef5736154@proton.me Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

udf: validate free block extents against the partition length

2026-07-24T14:02:51+00:00

commit 5f0419457f89dce1a3f1c8e62a3adf2f39ab8168 upstream. udf_free_blocks() checks the logical block number and count against the partition length, but drops the extent offset from that final bound. A crafted extent can pass the guard while logicalBlockNum + offset + count points past the partition, which later indexes past the space bitmap array. A single ftruncate(2) on a file backed by such an extent reliably panics the kernel. This is a local availability issue. On desktop systems where UDisks/polkit allows the active user to mount removable UDF media without CAP_SYS_ADMIN, an unprivileged local user can supply the crafted filesystem and trigger the panic by truncating a writable file on it. Systems that require root or CAP_SYS_ADMIN to mount the image have a higher prerequisite. No confidentiality or integrity impact is claimed: the reproduced primitive is an out-of-bounds read of a bitmap pointer slot followed by a kernel panic. Use the already computed logicalBlockNum + offset + count value for the partition length check. Also make load_block_bitmap() reject an out-of-range block group before indexing s_block_bitmap[], so corrupted callers cannot walk past the flexible array. Fixes: 56e69e59751d ("udf: prevent integer overflow in udf_bitmap_free_blocks()") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/20260515142327.1120767-1-michael.bommarito@gmail.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

udf: fix partition descriptor append bookkeeping

2026-05-17T15:13:49+00:00

[ Upstream commit 08841b06fa64d8edbd1a21ca6e613420c90cc4b8 ] Mounting a crafted UDF image with repeated partition descriptors can trigger a heap out-of-bounds write in part_descs_loc[]. handle_partition_descriptor() deduplicates entries by partition number, but appended slots never record partnum. As a result duplicate Partition Descriptors are appended repeatedly and num_part_descs keeps growing. Once the table is full, the growth path still sizes the allocation from partnum even though inserts are indexed by num_part_descs. If partnum is already aligned to PART_DESC_ALLOC_STEP, ALIGN(partnum, step) can keep the old capacity and the next append writes past the end of the table. Store partnum in the appended slot and size growth from the next append count so deduplication and capacity tracking follow the same model. Fixes: ee4af50ca94f ("udf: Fix mounting of Win7 created UDF filesystems") Cc: stable@vger.kernel.org Signed-off-by: Seohyeon Maeng Link: https://patch.msgid.link/20260310081652.21220-1-bioloidgp@gmail.com Signed-off-by: Jan Kara [ replaced kzalloc_objs() helper with equivalent kcalloc() ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

udf: reject descriptors with oversized CRC length

2026-05-17T15:13:40+00:00

commit 55d41b0a20128e86b9e960dd2e3f0a2d69a18df7 upstream. udf_read_tagged() skips CRC verification when descCRCLength + sizeof(struct tag) exceeds the block size. A crafted UDF image can set descCRCLength to an oversized value to bypass CRC validation entirely; the descriptor is then accepted based solely on the 8-bit tag checksum, which is trivially recomputable. Reject such descriptors instead of silently accepting them. A legitimate single-block descriptor should never have a CRC length that exceeds the block. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/20260413211240.853662-1-michael.bommarito@gmail.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

fs: udf: fix OOB read in lengthAllocDescs handling

2025-10-15T09:58:08+00:00

commit 3bd5e45c2ce30e239d596becd5db720f7eb83c99 upstream. When parsing Allocation Extent Descriptor, lengthAllocDescs comes from on-disk data and must be validated against the block size. Crafted or corrupted images may set lengthAllocDescs so that the total descriptor length (sizeof(allocExtDesc) + lengthAllocDescs) exceeds the buffer, leading udf_update_tag() to call crc_itu_t() on out-of-bounds memory and trigger a KASAN use-after-free read. BUG: KASAN: use-after-free in crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60 Read of size 1 at addr ffff888041e7d000 by task syz-executor317/5309 CPU: 0 UID: 0 PID: 5309 Comm: syz-executor317 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60 udf_update_tag+0x70/0x6a0 fs/udf/misc.c:261 udf_write_aext+0x4d8/0x7b0 fs/udf/inode.c:2179 extent_trunc+0x2f7/0x4a0 fs/udf/truncate.c:46 udf_truncate_tail_extent+0x527/0x7e0 fs/udf/truncate.c:106 udf_release_file+0xc1/0x120 fs/udf/file.c:185 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa2f/0x28e0 kernel/exit.c:939 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 __do_sys_exit_group kernel/exit.c:1099 [inline] __se_sys_exit_group kernel/exit.c:1097 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Validate the computed total length against epos->bh->b_size. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Reported-by: syzbot+8743fca924afed42f93e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=8743fca924afed42f93e Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Larshin Sergey Link: https://patch.msgid.link/20250922131358.745579-1-Sergey.Larshin@kaspersky.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman