staging: ccree: copy IV to DMAable memory

We are being passed an IV buffer from unknown origin, which may be
stack allocated and thus not safe for DMA. Allocate a DMA safe
buffer for the IV and use that instead.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 19 insertions, 2 deletions

diff --git a/drivers/staging/ccree/ssi_cipher.c b/drivers/staging/ccree/ssi_cipher.c
index 78706f5bcfb4..0b691034e6f5 100644
--- a/drivers/staging/ccree/ssi_cipher.c
+++ b/drivers/staging/ccree/ssi_cipher.c
@@ -695,6 +695,7 @@ static int ssi_blkcipher_complete(struct device *dev,
         struct ablkcipher_request *req = (struct ablkcipher_request *)areq;
 
         ssi_buffer_mgr_unmap_blkcipher_request(dev, req_ctx, ivsize, src, dst);
+        kfree(req_ctx->iv);
 
         /*Decrease the inflight counter*/
         if (ctx_p->flow_mode == BYPASS && ctx_p->drvdata->inflight_counter > 0)
@@ -757,6 +758,17 @@ static int ssi_blkcipher_process(
                 rc = 0;
                 goto exit_process;
         }
+
+        /* The IV we are handed may be allocted from the stack so
+         * we must copy it to a DMAable buffer before use.
+         */
+        req_ctx->iv = kmalloc(ivsize, GFP_KERNEL);
+        if (!req_ctx->iv) {
+                rc = -ENOMEM;
+                goto exit_process;
+        }
+        memcpy(req_ctx->iv, info, ivsize);
+
         /*For CTS in case of data size aligned to 16 use CBC mode*/
         if (((nbytes % AES_BLOCK_SIZE) == 0) && (ctx_p->cipher_mode == DRV_CIPHER_CBC_CTS)) {
                 ctx_p->cipher_mode = DRV_CIPHER_CBC;
@@ -778,7 +790,9 @@ static int ssi_blkcipher_process(
 
         /* STAT_PHASE_1: Map buffers */
 
-        rc = ssi_buffer_mgr_map_blkcipher_request(ctx_p->drvdata, req_ctx, ivsize, nbytes, info, src, dst);
+        rc = ssi_buffer_mgr_map_blkcipher_request(ctx_p->drvdata, req_ctx,
+                                                  ivsize, nbytes, req_ctx->iv,
+                                                  src, dst);
         if (unlikely(rc != 0)) {
                 dev_err(dev, "map_request() failed\n");
                 goto exit_process;
@@ -830,8 +844,10 @@ exit_process:
         if (cts_restore_flag != 0)
                 ctx_p->cipher_mode = DRV_CIPHER_CBC_CTS;
 
-        if (rc != -EINPROGRESS)
+        if (rc != -EINPROGRESS) {
                 kfree(req_ctx->backup_info);
+                kfree(req_ctx->iv);
+        }
 
         return rc;
 }
diff --git a/drivers/staging/ccree/ssi_cipher.h b/drivers/staging/ccree/ssi_cipher.h
index f4999626b94a..25e6335c0d94 100644
--- a/drivers/staging/ccree/ssi_cipher.h
+++ b/drivers/staging/ccree/ssi_cipher.h
@@ -43,6 +43,7 @@ struct blkcipher_req_ctx {
         u32 out_nents;
         u32 out_mlli_nents;
         u8 *backup_info; /*store iv for generated IV flow*/
+        u8 *iv;
         bool is_giv;
         struct mlli_params mlli_params;
 };