- Description
- In the Linux kernel, the following vulnerability has been resolved: ntfs: avoid calling post_write_mst_fixup() for invalid index_block ntfs_icx_ib_sync_write() calls post_write_mst_fixup() when ntfs_ib_write() returns an error, intending to restore the buffer after a failed write. However, ntfs_ib_write() returns an error immediately if pre_write_mst_fixup() validation fails. The caller, ntfs_icx_ib_sync_write(), interprets any error as a write failure requiring rollback. It does not differentiate between I/O errors and validation failures, and calls post_write_mst_fixup() anyway. Since post_write_mst_fixup() assumes that the index_block contents is correct, it doesn't perform the boundary checks, which results in out-of-bounds memory access. An attacker can craft a malicious NTFS image with: - large index_block.usa_ofs offset, pointing outside the ntfs_record - index_block.usa_count = 0, causing integer underflow - or index_block.usa_count larger than actual number of sectors in the ntfs_record, causing out-of-bounds access KASAN reports describing the memory corruption: ================================================================== BUG: KASAN: slab-out-of-bounds in post_write_mst_fixup+0x19c/0x1d0 Read of size 2 at addr ffff8881586c9018 by task p/9428 Call Trace: <TASK> dump_stack_lvl+0x100/0x190 print_report+0x139/0x4ad ? post_write_mst_fixup+0x19c/0x1d0 ? __virt_addr_valid+0x262/0x500 ? post_write_mst_fixup+0x19c/0x1d0 kasan_report+0xe4/0x1d0 ? post_write_mst_fixup+0x19c/0x1d0 post_write_mst_fixup+0x19c/0x1d0 ntfs_icx_ib_sync_write+0x179/0x220 ntfs_inode_sync_filename+0x83d/0x1080 __ntfs_write_inode+0x1049/0x1480 ntfs_file_fsync+0x131/0x9b0 ================================================================== BUG: KASAN: slab-out-of-bounds in post_write_mst_fixup+0x1aa/0x1d0 Write of size 2 at addr ffff8881586c91fe by task p/9428 Call Trace: <TASK> dump_stack_lvl+0x100/0x190 print_report+0x139/0x4ad ? post_write_mst_fixup+0x1aa/0x1d0 ? __virt_addr_valid+0x262/0x500 ? post_write_mst_fixup+0x1aa/0x1d0 kasan_report+0xe4/0x1d0 ? post_write_mst_fixup+0x1aa/0x1d0 post_write_mst_fixup+0x1aa/0x1d0 ntfs_icx_ib_sync_write+0x179/0x220 ntfs_inode_sync_filename+0x83d/0x1080 __ntfs_write_inode+0x1049/0x1480 ntfs_file_fsync+0x131/0x9b0 ================================================================== Let's move the post_write_mst_fixup() call to ntfs_ib_write(). The ntfs_ib_write() function calls pre_write_mst_fixup() at the beginning. If the index_block contents is invalid, pre_write_mst_fixup() fails and ntfs_ib_write() returns early without calling post_write_mst_fixup() on bad index_block.
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- NVD status
- Analyzed
- Products
- linux_kernel
CVSS 3.1
- Type
- Secondary
- Base score
- 7.8
- Impact score
- 5.9
- Exploitability score
- 1.8
- Vector string
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Severity
- HIGH
- nvd@nist.gov
- CWE-787
- Hype score
- Not currently trending
[
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "7D22B17B-4F96-43BE-835F-3A80228838B0",
"versionEndExcluding": "7.1.4",
"versionStartIncluding": "7.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.2:rc1:*:*:*:*:*:*",
"matchCriteriaId": "5E8B9085-7ADB-4A05-89EF-12949B6A0509",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:*",
"matchCriteriaId": "1FC0D50D-9D58-4947-A197-A5A3FF07E7E3",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
]