From 043b4307a99f902697349128fde93b2ddde4686c Mon Sep 17 00:00:00 2001 From: YunJe Shin Date: Wed, 28 Jan 2026 09:41:07 +0900 Subject: nvmet-tcp: add bounds checks in nvmet_tcp_build_pdu_iovec [ Upstream commit 52a0a98549344ca20ad81a4176d68d28e3c05a5c ] nvmet_tcp_build_pdu_iovec() could walk past cmd->req.sg when a PDU length or offset exceeds sg_cnt and then use bogus sg->length/offset values, leading to _copy_to_iter() GPF/KASAN. Guard sg_idx, remaining entries, and sg->length/offset before building the bvec. Fixes: 872d26a391da ("nvmet-tcp: add NVMe over TCP target driver") Signed-off-by: YunJe Shin Reviewed-by: Sagi Grimberg Reviewed-by: Joonkyo Jung Signed-off-by: Keith Busch Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/nvme/target/tcp.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index 6fd4f74315f6..b2c865282fd8 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -294,11 +294,14 @@ static void nvmet_tcp_free_cmd_buffers(struct nvmet_tcp_cmd *cmd) cmd->req.sg = NULL; } +static void nvmet_tcp_fatal_error(struct nvmet_tcp_queue *queue); + static void nvmet_tcp_build_pdu_iovec(struct nvmet_tcp_cmd *cmd) { struct bio_vec *iov = cmd->iov; struct scatterlist *sg; u32 length, offset, sg_offset; + unsigned int sg_remaining; int nr_pages; length = cmd->pdu_len; @@ -306,17 +309,32 @@ static void nvmet_tcp_build_pdu_iovec(struct nvmet_tcp_cmd *cmd) offset = cmd->rbytes_done; cmd->sg_idx = offset / PAGE_SIZE; sg_offset = offset % PAGE_SIZE; + if (!cmd->req.sg_cnt || cmd->sg_idx >= cmd->req.sg_cnt) { + nvmet_tcp_fatal_error(cmd->queue); + return; + } sg = &cmd->req.sg[cmd->sg_idx]; + sg_remaining = cmd->req.sg_cnt - cmd->sg_idx; while (length) { u32 iov_len = min_t(u32, length, sg->length - sg_offset); + if (!sg_remaining) { + nvmet_tcp_fatal_error(cmd->queue); + return; + } + if (!sg->length || sg->length <= sg_offset) { + nvmet_tcp_fatal_error(cmd->queue); + return; + } + iov->bv_page = sg_page(sg); iov->bv_len = sg->length; iov->bv_offset = sg->offset + sg_offset; length -= iov_len; sg = sg_next(sg); + sg_remaining--; iov++; sg_offset = 0; } -- cgit v1.2.3