swiotlb: Fix double-allocation of slots due to broken alignment handling

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2024-35814
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2024-05-17 14:15:15 UTC
Updated2026-08-04 11:17:55 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: swiotlb: Fix double-allocation of slots due to broken alignment handling Commit bbb73a103fbb ("swiotlb: fix a braino in the alignment check fix"), which was a fix for commit 0eee5ae10256 ("swiotlb: fix slot alignment checks"), causes a functional regression with vsock in a virtual machine using bouncing via a restricted DMA SWIOTLB pool. When virtio allocates the virtqueues for the vsock device using dma_alloc_coherent(), the SWIOTLB search can return page-unaligned allocations if 'area->index' was left unaligned by a previous allocation from the buffer: # Final address in brackets is the SWIOTLB address returned to the caller | virtio-pci 0000:00:07.0: orig_addr 0x0 alloc_size 0x2000, iotlb_align_mask 0x800 stride 0x2: got slot 1645-1649/7168 (0x98326800) | virtio-pci 0000:00:07.0: orig_addr 0x0 alloc_size 0x2000, iotlb_align_mask 0x800 stride 0x2: got slot 1649-1653/7168 (0x98328800) | virtio-pci 0000:00:07.0: orig_addr 0x0 alloc_size 0x2000, iotlb_align_mask 0x800 stride 0x2: got slot 1653-1657/7168 (0x9832a800) This ends badly (typically buffer corruption and/or a hang) because swiotlb_alloc() is expecting a page-aligned allocation and so blindly returns a pointer to the 'struct page' corresponding to the allocation, therefore double-allocating the first half (2KiB slot) of the 4KiB page. Fix the problem by treating the allocation alignment separately to any additional alignment requirements from the device, using the maximum of the two as the stride to search the buffer slots and taking care to ensure a minimum of page-alignment for buffers larger than a page. This also resolves swiotlb allocation failures occuring due to the inclusion of ~PAGE_MASK in 'iotlb_align_mask' for large allocations and resulting in alignment requirements exceeding swiotlb_max_mapping_size().

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Problem Types: CWE-415 | CWE-119 | CWE-1055 | CWE-119 CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer | CWE-1055 CWE-1055 Multiple Inheritance from Concrete Classes

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary8.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1ADPDECLARED7.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 0eee5ae1025699ea93d44fdb6ef2365505082103 3e7acd6e25ba77dde48c3b721c54c89cd6a10534 git Not specified
CNA Linux Linux affected 0eee5ae1025699ea93d44fdb6ef2365505082103 c88668aa6c1da240ea3eb4d128b7906e740d3cb8 git Not specified
CNA Linux Linux affected 0eee5ae1025699ea93d44fdb6ef2365505082103 777391743771040e12cc40d3d0d178f70c616491 git Not specified
CNA Linux Linux affected 0eee5ae1025699ea93d44fdb6ef2365505082103 04867a7a33324c9c562ee7949dbcaab7aaad1fb4 git Not specified
CNA Linux Linux affected 6.3 Not specified
CNA Linux Linux unaffected 6.3 semver Not specified
CNA Linux Linux unaffected 6.6.24 6.6.* semver Not specified
CNA Linux Linux unaffected 6.7.12 6.7.* semver Not specified
CNA Linux Linux unaffected 6.8.3 6.8.* semver Not specified
CNA Linux Linux unaffected 6.9 * original_commit_for_fix Not specified
ADP Linux Linux Kernel affected 0eee5ae10256 3e7acd6e25ba custom Not specified
ADP Linux Linux Kernel affected 0eee5ae10256 c88668aa6c1d custom Not specified
ADP Linux Linux Kernel affected 0eee5ae10256 777391743771 custom Not specified
ADP Linux Linux Kernel affected 0eee5ae10256 04867a7a3332 custom Not specified
ADP Linux Linux Kernel affected 6.3 Not specified
ADP Linux Linux Kernel unaffected 6.3 custom Not specified
ADP Linux Linux Kernel unaffected 6.6.24 6.6.* custom Not specified
ADP Linux Linux Kernel unaffected 6.7.12 6.7.* custom Not specified
ADP Linux Linux Kernel unaffected 6.8.3 6.8.* custom Not specified
ADP Linux Linux Kernel unaffected 6.9 Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/777391743771040e12cc40d3d0d178f70c616491 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/04867a7a33324c9c562ee7949dbcaab7aaad1fb4 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/c88668aa6c1da240ea3eb4d128b7906e740d3cb8 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/3e7acd6e25ba77dde48c3b721c54c89cd6a10534 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
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