Bug 2492774 (CVE-2026-53170)

Summary: CVE-2026-53170 kernel: accel/ethosu: reject DMA commands with uninitialized length
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `accel/ethosu` driver. A local attacker could exploit a vulnerability where DMA commands with uninitialized length are not properly handled. By omitting a specific DMA length setup command and issuing a DMA start command, a user could bypass bounds checks, allowing the hardware to execute DMA operations with stale physical addresses. This could lead to memory corruption, potentially resulting in privilege escalation or arbitrary code execution.
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Description OSIDB Bzimport 2026-06-25 10:05:00 UTC 
In the Linux kernel, the following vulnerability has been resolved:

accel/ethosu: reject DMA commands with uninitialized length

cmd_state_init() initializes the command state with memset(0xff),
leaving dma->len at U64_MAX to signal missing setup. The only setter
is NPU_SET_DMA0_LEN; if userspace omits this command and issues
NPU_OP_DMA_START, dma->len remains U64_MAX.

In dma_length(), a positive stride added to U64_MAX wraps to a small
value. With size0 == 1, check_mul_overflow() does not trigger and
dma_length() returns 0 instead of U64_MAX. The caller's U64_MAX check
then passes, region_size[] stays 0, and the bounds check in
ethosu_job.c is bypassed, allowing hardware to execute DMA with stale
physical addresses.

Fix by checking for U64_MAX at the start of dma_length() before any
arithmetic, consistent with the sentinel value used throughout the
driver to detect uninitialized fields.
Comment 1 Keith Grant 2026-06-25 23:58:06 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062552-CVE-2026-53170-29c9@gregkh/T