CVE-2023-53778

accel/qaic: Clean up integer overflow checking in map_user_pages()

Published Dec 9, 2025 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

accel/qaic: Clean up integer overflow checking in map_user_pages()

The encode_dma() function has some validation on in_trans->size but it
would be more clear to move those checks to find_and_map_user_pages().

The encode_dma() had two checks:

if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size)
return -EINVAL;

The in_trans->addr variable is the starting address. The in_trans->size
variable is the total size of the transfer. The transfer can occur in
parts and the resources->xferred_dma_size tracks how many bytes we have
already transferred.

This patch introduces a new variable "remaining" which represents the
amount we want to transfer (in_trans->size) minus the amount we have
already transferred (resources->xferred_dma_size).

I have modified the check for if in_trans->size is zero to instead check
if in_trans->size is less than resources->xferred_dma_size. If we have
already transferred more bytes than in_trans->size then there are negative
bytes remaining which doesn't make sense. If there are zero bytes
remaining to be copied, just return success.

The check in encode_dma() checked that "addr + size" could not overflow
and barring a driver bug that should work, but it's easier to check if
we do this in parts. First check that "in_trans->addr +
resources->xferred_dma_size" is safe. Then check that "xfer_start_addr +
remaining" is safe.

My final concern was that we are dealing with u64 values but on 32bit
systems the kmalloc() function will truncate the sizes to 32 bits. So
I calculated "total = in_trans->size + offset_in_page(xfer_start_addr);"
and returned -EINVAL if it were >= SIZE_MAX. This will not affect 64bit
systems.

Analysis

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Remediation

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Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: accel/qaic: Clean up integer overflow checking in map_user_pages() The encode_dma() function has some validation on in_trans->size but it would be more clear to move those checks to find_and_map_user_pages(). The encode_dma() had two checks: if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size) return -EINVAL; The in_trans->addr variable is the starting address. The in_trans->size variable is the total size of the transfer. The transfer can occur in parts and the resources->xferred_dma_size tracks how many bytes we have already transferred. This patch introduces a new variable "remaining" which represents the amount we want to transfer (in_trans->size) minus the amount we have already transferred (resources->xferred_dma_size). I have modified the check for if in_trans->size is zero to instead check if in_trans->size is less than resources->xferred_dma_size. If we have already transferred more bytes than in_trans->size then there are negative bytes remaining which doesn't make sense. If there are zero bytes remaining to be copied, just return success. The check in encode_dma() checked that "addr + size" could not overflow and barring a driver bug that should work, but it's easier to check if we do this in parts. First check that "in_trans->addr + resources->xferred_dma_size" is safe. Then check that "xfer_start_addr + remaining" is safe. My final concern was that we are dealing with u64 values but on 32bit systems the kmalloc() function will truncate the sizes to 32 bits. So I calculated "total = in_trans->size + offset_in_page(xfer_start_addr);" and returned -EINVAL if it were >= SIZE_MAX. This will not affect 64bit systems.
Title accel/qaic: Clean up integer overflow checking in map_user_pages()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

No weakness.

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 5, 2026, 9:15 AM
Reserved
Dec 8, 2025, 11:58 PM
Status
Deferred
Published
Dec 9, 2025, 1:16 AM
Modified
Aug 4, 2026, 10:19 AM
Severity
Moderate
Public date
Dec 9, 2025, 12:00 AM