Re: [PATCH net v2] net: bgmac: fix oversized RX frame check
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From: Florian Fainelli <florian.fainelli@broadcom.com>
Date: 2026-10-28 17:00:12
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On 10/27/26 18:10, Rosen Penev wrote:
While reviewing commit 77dac783f11
("net: bgmac: rate limit RX error messages") , Florian spotted that the RX
length sanity check compares the length reported in the RX header against
BGMAC_RX_ALLOC_SIZE. That is the size of the whole fragment, including the
space reserved for struct skb_shared_info. The data area handed to the
hardware is only BGMAC_RX_BUF_SIZE bytes, and the frame starts
BGMAC_RX_FRAME_OFFSET bytes into it, so a valid frame is at most
BGMAC_RX_MAX_FRAME_SIZE bytes long.
A corrupted length between those two limits passes the check, and the
following skb_put() runs past the skb tailroom and calls
skb_over_panic() instead of dropping the frame.
Compare against BGMAC_RX_MAX_FRAME_SIZE instead.
Only compile tested. Not tested on hardware.
Fixes: 6a6c708469c9 ("bgmac: add check for oversized packets")
Signed-off-by: Rosen Penev <redacted>Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> -- Florian