From: Sagi Grimberg <sagi@grimberg.me>
Date: Sun, 13 Nov 2022 13:24:13 +0200
Subject: nvme-auth: don't keep long lived 4k dhchap buffer
Patch-mainline: v6.2-rc1
Git-commit: b7d604cae8f6edde53ac8aa9038ee154be562eb5
References: bsc#1202633

dhchap structure is per-queue, it is wasteful to keep it for the entire
lifetime of the queue. Allocate it dynamically and get rid of it after
authentication. We don't need kzalloc because all accessors are clearing
it before writing to it.

Also, remove redundant chap buf_size which is always 4096, use a define
instead.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/auth.c |   47 ++++++++++++++++++++++++-----------------------
 1 file changed, 24 insertions(+), 23 deletions(-)

--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -13,6 +13,8 @@
 #include "fabrics.h"
 #include <linux/nvme-auth.h>
 
+#define CHAP_BUF_SIZE 4096
+
 struct nvme_dhchap_queue_context {
 	struct list_head entry;
 	struct work_struct auth_work;
@@ -20,7 +22,6 @@ struct nvme_dhchap_queue_context {
 	struct crypto_shash *shash_tfm;
 	struct crypto_kpp *dh_tfm;
 	void *buf;
-	size_t buf_size;
 	int qid;
 	int error;
 	u32 s1;
@@ -112,7 +113,7 @@ static int nvme_auth_set_dhchap_negotiat
 	struct nvmf_auth_dhchap_negotiate_data *data = chap->buf;
 	size_t size = sizeof(*data) + sizeof(union nvmf_auth_protocol);
 
-	if (chap->buf_size < size) {
+	if (size > CHAP_BUF_SIZE) {
 		chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD;
 		return -EINVAL;
 	}
@@ -147,7 +148,7 @@ static int nvme_auth_process_dhchap_chal
 	const char *gid_name = nvme_auth_dhgroup_name(data->dhgid);
 	const char *hmac_name, *kpp_name;
 
-	if (chap->buf_size < size) {
+	if (size > CHAP_BUF_SIZE) {
 		chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD;
 		return NVME_SC_INVALID_FIELD;
 	}
@@ -302,7 +303,7 @@ static int nvme_auth_set_dhchap_reply_da
 	if (chap->host_key_len)
 		size += chap->host_key_len;
 
-	if (chap->buf_size < size) {
+	if (size > CHAP_BUF_SIZE) {
 		chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD;
 		return -EINVAL;
 	}
@@ -347,7 +348,7 @@ static int nvme_auth_process_dhchap_succ
 	if (ctrl->ctrl_key)
 		size += chap->hash_len;
 
-	if (chap->buf_size < size) {
+	if (size > CHAP_BUF_SIZE) {
 		chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD;
 		return NVME_SC_INVALID_FIELD;
 	}
@@ -674,6 +675,8 @@ static void nvme_auth_reset_dhchap(struc
 	chap->transaction = 0;
 	memset(chap->c1, 0, sizeof(chap->c1));
 	memset(chap->c2, 0, sizeof(chap->c2));
+	kfree(chap->buf);
+	chap->buf = NULL;
 }
 
 static void nvme_auth_free_dhchap(struct nvme_dhchap_queue_context *chap)
@@ -683,7 +686,6 @@ static void nvme_auth_free_dhchap(struct
 		crypto_free_shash(chap->shash_tfm);
 	if (chap->dh_tfm)
 		crypto_free_kpp(chap->dh_tfm);
-	kfree(chap->buf);
 	kfree(chap);
 }
 
@@ -695,6 +697,16 @@ static void nvme_queue_auth_work(struct
 	size_t tl;
 	int ret = 0;
 
+	/*
+	 * Allocate a large enough buffer for the entire negotiation:
+	 * 4k is enough to ffdhe8192.
+	 */
+	chap->buf = kmalloc(CHAP_BUF_SIZE, GFP_KERNEL);
+	if (!chap->buf) {
+		chap->error = -ENOMEM;
+		return;
+	}
+
 	chap->transaction = ctrl->transaction++;
 
 	/* DH-HMAC-CHAP Step 1: send negotiate */
@@ -716,8 +728,9 @@ static void nvme_queue_auth_work(struct
 	dev_dbg(ctrl->device, "%s: qid %d receive challenge\n",
 		__func__, chap->qid);
 
-	memset(chap->buf, 0, chap->buf_size);
-	ret = nvme_auth_submit(ctrl, chap->qid, chap->buf, chap->buf_size, false);
+	memset(chap->buf, 0, CHAP_BUF_SIZE);
+	ret = nvme_auth_submit(ctrl, chap->qid, chap->buf, CHAP_BUF_SIZE,
+			       false);
 	if (ret) {
 		dev_warn(ctrl->device,
 			 "qid %d failed to receive challenge, %s %d\n",
@@ -779,8 +792,9 @@ static void nvme_queue_auth_work(struct
 	dev_dbg(ctrl->device, "%s: qid %d receive success1\n",
 		__func__, chap->qid);
 
-	memset(chap->buf, 0, chap->buf_size);
-	ret = nvme_auth_submit(ctrl, chap->qid, chap->buf, chap->buf_size, false);
+	memset(chap->buf, 0, CHAP_BUF_SIZE);
+	ret = nvme_auth_submit(ctrl, chap->qid, chap->buf, CHAP_BUF_SIZE,
+			       false);
 	if (ret) {
 		dev_warn(ctrl->device,
 			 "qid %d failed to receive success1, %s %d\n",
@@ -876,19 +890,6 @@ int nvme_auth_negotiate(struct nvme_ctrl
 	}
 	chap->qid = qid;
 	chap->ctrl = ctrl;
-
-	/*
-	 * Allocate a large enough buffer for the entire negotiation:
-	 * 4k should be enough to ffdhe8192.
-	 */
-	chap->buf_size = 4096;
-	chap->buf = kzalloc(chap->buf_size, GFP_KERNEL);
-	if (!chap->buf) {
-		mutex_unlock(&ctrl->dhchap_auth_mutex);
-		kfree(chap);
-		return -ENOMEM;
-	}
-
 	INIT_WORK(&chap->auth_work, nvme_queue_auth_work);
 	list_add(&chap->entry, &ctrl->dhchap_auth_list);
 	mutex_unlock(&ctrl->dhchap_auth_mutex);