[PATCH v2 1/3] staging: ccree: copy IV to DMAable memory

From: Gilad Ben-Yossef
Date: Thu Nov 02 2017 - 04:12:03 EST


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@xxxxxxxxxxxxx>
---
drivers/staging/ccree/ssi_cipher.c | 20 ++++++++++++++++++--
drivers/staging/ccree/ssi_cipher.h | 1 +
2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/ccree/ssi_cipher.c b/drivers/staging/ccree/ssi_cipher.c
index 78706f5..0b69103 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 @@ static int ssi_blkcipher_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 f499962..25e6335 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;
};
--
2.7.4