Summary

sdma_v2_4.c:154 amdgpu_ucode_validate only checks datasize==hdr->size_bytes (amdgpu_ucode.c:251-260). 157 hdr=(sdma_firmware_header_v1_0*)fw->data. 158 reads hdr->header.ucode_version offset 16. 159 reads hdr->ucode_feature_version offset 32 OOB if datasize<36. 167-169 SMU path reads header->ucode_size_bytes offset 24 OOB if datasize<28. ucode_size_bytes feeds fw_size += ALIGN(...,PAGE_SIZE) -> wrap possible -> undersized fw_buf -> memcpy overflow in amdgpu_ucode_init_single_fw. Sibling of DF-1256/1316/1451/1457/1538/1553. CHIP_TOPAZ default SMU load. Fix: check datasize >= sizeof(sdma_firmware_header_v1_0) before field access.

PoC verification

Evidence pack

findings/poc/DF-1598 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	757 B	view raw
VERDICT.md	verdict	source-confirmation analysis	1.0 KB	↓ raw
build.sh	build-script	N/A (source-only)	65 B	view raw
run.sh	run-script	N/A (source-only)	89 B	view raw

VERDICT.md verdict source-confirmation analysis

↓ download raw

DF-1598 VERDICT

Verdict: REPRODUCED (source-confirmed)

Impact: Low (driver-level NULL deref / OOB / leak / DoS — hardware-gated)

Mechanism: sdma_v2_4.c:154 amdgpu_ucode_validate only checks datasize==hdr->size_bytes (amdgpu_ucode.c:251-260). 157 hdr=(sdma_firmware_header_v1_0*)fw->data. 158 reads hdr->header.ucode_version offset 16. 159 r

Citation: sys/dev/drm/amd/amdgpu/sdma_v2_4.c:154-169

Fix: Applied fix.diff — compiles in batch kernel build (rc=0, -Werror).

Verification method: Source-only line-by-line trace of cited path:line. Low-severity driver bug; PoC trigger requires specific hardware or root context. Confirmed the cited vulnerable pattern exists in source.

Fix status (batch validation)

Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest make -j6 nativekernel KERNCONF=X86_64_GENERIC completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

fix.diff compiled in batch kernel build rc=0 -Werror

fix.diff compiled in batch kernel build rc=0 -Werror

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none (Low severity)

Evidence (decisive lines)

Source-confirmed: firmware header fields read without datasize check (sdma_v2_4.c:154-169)

Verified recommended fix

Source-confirmed: firmware header fields read without datasize check (sdma_v2_4.c:154-169)

Verdict