[PATCH 5.4 11/71] nvme: Fix parsing of ANA log page

[Greg Kroah-Hartman]

From: Prabhath Sajeepa <psajeepa@xxxxxxxxxxxxxxx>

commit 64fab7290dc3561729bbc1e35895a517eb2e549e upstream.

Check validity of offset into ANA log buffer before accessing
nvme_ana_group_desc. This check ensures the size of ANA log buffer >=
offset + sizeof(nvme_ana_group_desc)

Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Signed-off-by: Prabhath Sajeepa <psajeepa@xxxxxxxxxxxxxxx>
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Cc: Uday Shankar <ushankar@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/nvme/host/multipath.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -458,8 +458,14 @@ static int nvme_parse_ana_log(struct nvm
 
 	for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
 		struct nvme_ana_group_desc *desc = base + offset;
-		u32 nr_nsids = le32_to_cpu(desc->nnsids);
-		size_t nsid_buf_size = nr_nsids * sizeof(__le32);
+		u32 nr_nsids;
+		size_t nsid_buf_size;
+
+		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
+			return -EINVAL;
+
+		nr_nsids = le32_to_cpu(desc->nnsids);
+		nsid_buf_size = nr_nsids * sizeof(__le32);
 
 		if (WARN_ON_ONCE(desc->grpid == 0))
 			return -EINVAL;
@@ -479,8 +485,6 @@ static int nvme_parse_ana_log(struct nvm
 			return error;
 
 		offset += nsid_buf_size;
-		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
-			return -EINVAL;
 	}
 
 	return 0;