wifi: ath12k: fix stale skb pointers after aligned TX payload shift

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ath12k_wifi7_dp_tx() caches hdr, eth, and skb_cb from the skb before
calling ath12k_dp_tx_align_payload(). That function may shift skb->data
in place (when headroom or tailroom is sufficient) or reallocate the
buffer entirely via skb_realloc_headroom(), freeing the original skb.
In either case hdr, eth, and skb_cb are left pointing into stale memory.

After alignment, only hdr is refreshed, leaving eth and skb_cb stale.
skb_cb is written immediately after (storing DMA addresses), and eth is
re-read on every TCL ring retry via the tcl_ring_sel goto, so both
accesses are use-after-free or stale-pointer bugs depending on which
alignment path was taken.

Refresh eth (conditionally, to preserve the encap-mode distinction) and
skb_cb alongside hdr after ath12k_dp_tx_align_payload() returns, so all
three point into the live skb for all subsequent accesses.

Issue found during code review, compile tested only.

Fixes: 38055789d1 ("wifi: ath12k: use 128 bytes aligned iova in transmit path for WCN7850")
Signed-off-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Link: https://patch.msgid.link/20260818-ath12k-uaf-for-aligned-tx-v1-1-d6ae195b15e7@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>

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This commit is contained in:

Baochen Qiang 2026-08-18 09:44:48 +08:00 • committed by Jeff Johnson

parent 4de5a8a0ed

commit 6c40719489

1 changed files with 7 additions and 2 deletions

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drivers/net/wireless/ath/ath12k/wifi7/dp_tx.c

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