From 7e6dcaeadc0ea240721a53a83bd45fc36e3eee3c Mon Sep 17 00:00:00 2001 From: Sagi Grimberg Date: Wed, 3 Feb 2021 01:20:25 -0800 Subject: [PATCH] nvmet-tcp: fix out-of-bounds access when receiving multiple h2cdata PDUs [ Upstream commit cb8563f5c735a042ea2dd7df1ad55ae06d63ffeb ] When the host sends multiple h2cdata PDUs, we keep track on the receive progress and calculate the scatterlist index and offsets. The issue is that sg_offset should only be kept for the first iov entry we map in the iovec as this is the difference between our cursor and the sg entry offset itself. In addition, the sg index was calculated wrong because we should not round up when dividing the command byte offset with PAG_SIZE. Fixes: 872d26a391da ("nvmet-tcp: add NVMe over TCP target driver") Reported-by: Narayan Ayalasomayajula Tested-by: Narayan Ayalasomayajula Signed-off-by: Sagi Grimberg Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- drivers/nvme/target/tcp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index e31823f19a0f..9242224156f5 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -292,7 +292,7 @@ static void nvmet_tcp_map_pdu_iovec(struct nvmet_tcp_cmd *cmd) length = cmd->pdu_len; cmd->nr_mapped = DIV_ROUND_UP(length, PAGE_SIZE); offset = cmd->rbytes_done; - cmd->sg_idx = DIV_ROUND_UP(offset, PAGE_SIZE); + cmd->sg_idx = offset / PAGE_SIZE; sg_offset = offset % PAGE_SIZE; sg = &cmd->req.sg[cmd->sg_idx]; @@ -305,6 +305,7 @@ static void nvmet_tcp_map_pdu_iovec(struct nvmet_tcp_cmd *cmd) length -= iov_len; sg = sg_next(sg); iov++; + sg_offset = 0; } iov_iter_kvec(&cmd->recv_msg.msg_iter, READ, cmd->iov,