From: David Carlier Date: Fri, 20 Mar 2026 17:44:39 +0000 (+0000) Subject: net: ti: icssg-prueth: fix use-after-free of CPPI descriptor in RX path X-Git-Tag: v7.0-rc6~40^2~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb8c426c9803beb171f89d15fea17505eb517714;p=thirdparty%2Fkernel%2Flinux.git net: ti: icssg-prueth: fix use-after-free of CPPI descriptor in RX path cppi5_hdesc_get_psdata() returns a pointer into the CPPI descriptor. In both emac_rx_packet() and emac_rx_packet_zc(), the descriptor is freed via k3_cppi_desc_pool_free() before the psdata pointer is used by emac_rx_timestamp(), which dereferences psdata[0] and psdata[1]. This constitutes a use-after-free on every received packet that goes through the timestamp path. Defer the descriptor free until after all accesses through the psdata pointer are complete. For emac_rx_packet(), move the free into the requeue label so both early-exit and success paths free the descriptor after all accesses are done. For emac_rx_packet_zc(), move the free to the end of the loop body after emac_dispatch_skb_zc() (which calls emac_rx_timestamp()) has returned. Fixes: 46eeb90f03e0 ("net: ti: icssg-prueth: Use page_pool API for RX buffer allocation") Signed-off-by: David Carlier Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260320174439.41080-1-devnexen@gmail.com Signed-off-by: Paolo Abeni --- diff --git a/drivers/net/ethernet/ti/icssg/icssg_common.c b/drivers/net/ethernet/ti/icssg/icssg_common.c index 0a3cf2f848a57..fd4e7622f1231 100644 --- a/drivers/net/ethernet/ti/icssg/icssg_common.c +++ b/drivers/net/ethernet/ti/icssg/icssg_common.c @@ -962,7 +962,6 @@ static int emac_rx_packet_zc(struct prueth_emac *emac, u32 flow_id, pkt_len -= 4; cppi5_desc_get_tags_ids(&desc_rx->hdr, &port_id, NULL); psdata = cppi5_hdesc_get_psdata(desc_rx); - k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx); count++; xsk_buff_set_size(xdp, pkt_len); xsk_buff_dma_sync_for_cpu(xdp); @@ -988,6 +987,7 @@ static int emac_rx_packet_zc(struct prueth_emac *emac, u32 flow_id, emac_dispatch_skb_zc(emac, xdp, psdata); xsk_buff_free(xdp); } + k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx); } if (xdp_status & ICSSG_XDP_REDIR) @@ -1057,7 +1057,6 @@ static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id, u32 *xdp_state) /* firmware adds 4 CRC bytes, strip them */ pkt_len -= 4; cppi5_desc_get_tags_ids(&desc_rx->hdr, &port_id, NULL); - k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx); /* if allocation fails we drop the packet but push the * descriptor back to the ring with old page to prevent a stall @@ -1115,6 +1114,7 @@ static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id, u32 *xdp_state) ndev->stats.rx_packets++; requeue: + k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx); /* queue another RX DMA */ ret = prueth_dma_rx_push_mapped(emac, &emac->rx_chns, new_page, PRUETH_MAX_PKT_SIZE);