CVE-2023-53778
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-09

Last updated on: 2025-12-09

Assigner: kernel.org

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.
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Meta Information
Published
2025-12-09
Last Modified
2025-12-09
Generated
2026-05-07
AI Q&A
2025-12-09
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability involves integer overflow checking in the Linux kernel's accel/qaic component, specifically in the map_user_pages() function. The encode_dma() function previously performed checks on the size and address of a data transfer, but these checks were improved and moved to find_and_map_user_pages() for clarity and safety. The issue was that the original checks could miss certain overflow conditions when calculating the total transfer size, especially when transfers occur in parts. The patch introduces a 'remaining' variable to track how many bytes are left to transfer and adds safer checks to prevent integer overflow and invalid size calculations, particularly addressing concerns on 32-bit systems where size truncation could occur. This prevents potential errors or unexpected behavior during DMA operations.


How can this vulnerability impact me? :

If exploited or triggered, this vulnerability could cause incorrect handling of memory transfers in the Linux kernel's accel/qaic driver, potentially leading to invalid memory accesses or data corruption due to integer overflow errors. This could affect system stability or security by allowing improper DMA operations, which might be leveraged by attackers or cause system crashes.


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