Re: [PATCH] nvmet-rdma: reject inline data with a nonzero offset

[Keith Busch <kbusch@kernel.org>]

On Thu, Jun 04, 2026 at 08:46:33AM +0000, Bryam Vargas wrote:
> It does stop the u64 overflow, but while testing it I found it is still
> incomplete when a port is configured with inline_data_size > PAGE_SIZE
> (it is settable up to max(SZ_16K, PAGE_SIZE)): an offset in
> (PAGE_SIZE, inline_data_size] passes that bound and then "PAGE_SIZE - off"
> in nvmet_rdma_use_inline_sg() underflows, leaving scatterlist::length at
> ~4 GiB pointing past the first inline page.

Then the use_inline_sg() should find the appropriate index and offset
accordingly.

---
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 1234567..abcdefg 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -821,22 +821,29 @@ static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
 		u64 off)
 {
-	int sg_count = num_pages(len);
+	u64 page_off = off % PAGE_SIZE;
+	u64 page_idx = off / PAGE_SIZE;
+	int sg_count = num_pages(page_off + len);
 	struct scatterlist *sg;
 	int i;
 
-	sg = rsp->cmd->inline_sg;
+	sg = &rsp->cmd->inline_sg[page_idx];
 	for (i = 0; i < sg_count; i++, sg++) {
 		if (i < sg_count - 1)
 			sg_unmark_end(sg);
 		else
 			sg_mark_end(sg);
-		sg->offset = off;
-		sg->length = min_t(int, len, PAGE_SIZE - off);
+		sg->offset = page_off;
+		sg->length = min_t(u64, len, PAGE_SIZE - page_off);
 		len -= sg->length;
-		if (!i)
-			off = 0;
+		page_off = 0;
 	}
 
-	rsp->req.sg = rsp->cmd->inline_sg;
+	rsp->req.sg = &rsp->cmd->inline_sg[page_idx];
 	rsp->req.sg_cnt = sg_count;
 }
 
@@ -857,7 +864,8 @@ static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
 			return NVME_SC_INVALID_FIELD | NVME_STATUS_DNR;
 	}
 
-	if (off + len > rsp->queue->dev->inline_data_size) {
+	if (off > rsp->queue->dev->inline_data_size ||
+	    len > rsp->queue->dev->inline_data_size - off) {
 		pr_err("invalid inline data offset!\n");
 		return NVME_SC_SGL_INVALID_OFFSET | NVME_STATUS_DNR;
 	}
--