Merge v7.1.4linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 22 insertions, 1 deletions

diff --git a/drivers/nvme/target/discovery.c b/drivers/nvme/target/discovery.c
index e9b35549e254..114869d16a1f 100644
--- a/drivers/nvme/target/discovery.c
+++ b/drivers/nvme/target/discovery.c
@@ -166,6 +166,7 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
 	u64 offset = nvmet_get_log_page_offset(req->cmd);
 	size_t data_len = nvmet_get_log_page_len(req->cmd);
 	size_t alloc_len;
+	size_t copy_len;
 	struct nvmet_subsys_link *p;
 	struct nvmet_port *r;
 	u32 numrec = 0;
@@ -242,7 +243,27 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
 
 	up_read(&nvmet_config_sem);
 
-	status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len);
+	/*
+	 * Validate the host-supplied log page offset before copying out.
+	 * Without this check, the host controls a 64-bit byte offset into
+	 * a small kzalloc'd buffer: a value past the log page lets the
+	 * subsequent memcpy read adjacent kernel heap, and a value aimed
+	 * at unmapped kernel memory faults the in-kernel copy and crashes
+	 * the target host. The Discovery controller is unauthenticated,
+	 * so the bug is reachable from any reachable fabric peer.
+	 */
+	if (offset > alloc_len) {
+		req->error_loc =
+			offsetof(struct nvme_get_log_page_command, lpo);
+		status = NVME_SC_INVALID_FIELD | NVME_STATUS_DNR;
+		goto out_free_buffer;
+	}
+
+	copy_len = min_t(size_t, data_len, alloc_len - offset);
+	status = nvmet_copy_to_sgl(req, 0, buffer + offset, copy_len);
+	if (!status && copy_len < data_len)
+		status = nvmet_zero_sgl(req, copy_len, data_len - copy_len);
+out_free_buffer:
 	kfree(buffer);
 out:
 	nvmet_req_complete(req, status);