From 9ff797e516dbc1ecb73701ec4c24055712d44411 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=A9my=20Jean?= Date: Tue, 8 Sep 2026 08:55:20 +0000 Subject: [PATCH] RDMA/siw: Bound fragmented header copies by the remaining length MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit siw_get_hdr() can receive an extended DDP/RDMAP header across more than one TCP callback. The first callback may receive most of the header, while the next one still limits the copy to hdrlen - MIN_DDP_HDR instead of the number of missing bytes. This makes the destination move past the end of the header and overwrite the receive state, including fpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd value as a copy offset, which creates an OOB write. Use the number of header bytes already received when calculating the next copy length. Fixes: 754209850df8 ("RDMA/siw: Always consume all skbuf data in sk_data_ready() upcall.") Signed-off-by: Jérémy Jean Link: https://patch.msgid.link/20260908085520.1746329-1-Jeremy.Jean@oss.cyber.gouv.fr Assisted-by: Codex:gpt-6 Acked-by: Bernard Metzler Signed-off-by: Leon Romanovsky --- drivers/infiniband/sw/siw/siw_qp_rx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/siw/siw_qp_rx.c b/drivers/infiniband/sw/siw/siw_qp_rx.c index b566d163c5aa..e5b641c8d694 100644 --- a/drivers/infiniband/sw/siw/siw_qp_rx.c +++ b/drivers/infiniband/sw/siw/siw_qp_rx.c @@ -1079,7 +1079,7 @@ static int siw_get_hdr(struct siw_rx_stream *srx) if (iwarp_pktinfo[opcode].hdr_len > sizeof(struct iwarp_ctrl_tagged)) { int hdrlen = iwarp_pktinfo[opcode].hdr_len; - bytes = min_t(int, hdrlen - MIN_DDP_HDR, srx->skb_new); + bytes = min_t(int, hdrlen - srx->fpdu_part_rcvd, srx->skb_new); skb_copy_bits(skb, srx->skb_offset, (char *)c_hdr + srx->fpdu_part_rcvd, bytes);