[PATCH] crypto: ccree: Correctly handle return of sg_nents_for_len

[Haotian Zhang <vulab@iscas.ac.cn>]

Fix error handling in cc_map_hash_request_update where sg_nents_for_len
return value was assigned to u32, converting negative errors to large
positive values before passing to sg_copy_to_buffer.

Check sg_nents_for_len return value and propagate errors before
assigning to areq_ctx->in_nents.

Fixes: b7ec8530687a ("crypto: ccree - use std api when possible")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
---
 drivers/crypto/ccree/cc_buffer_mgr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/ccree/cc_buffer_mgr.c b/drivers/crypto/ccree/cc_buffer_mgr.c
index 3963bb91321f..dc7e0cd51c25 100644
--- a/drivers/crypto/ccree/cc_buffer_mgr.c
+++ b/drivers/crypto/ccree/cc_buffer_mgr.c
@@ -1235,6 +1235,7 @@ int cc_map_hash_request_update(struct cc_drvdata *drvdata, void *ctx,
 	int rc = 0;
 	u32 dummy = 0;
 	u32 mapped_nents = 0;
+	int sg_nents;
 
 	dev_dbg(dev, " update params : curr_buff=%p curr_buff_cnt=0x%X nbytes=0x%X src=%p curr_index=%u\n",
 		curr_buff, *curr_buff_cnt, nbytes, src, areq_ctx->buff_index);
@@ -1248,7 +1249,10 @@ int cc_map_hash_request_update(struct cc_drvdata *drvdata, void *ctx,
 	if (total_in_len < block_size) {
 		dev_dbg(dev, " less than one block: curr_buff=%p *curr_buff_cnt=0x%X copy_to=%p\n",
 			curr_buff, *curr_buff_cnt, &curr_buff[*curr_buff_cnt]);
-		areq_ctx->in_nents = sg_nents_for_len(src, nbytes);
+		sg_nents = sg_nents_for_len(src, nbytes);
+		if (sg_nents < 0)
+			return sg_nents;
+		areq_ctx->in_nents = sg_nents;
 		sg_copy_to_buffer(src, areq_ctx->in_nents,
 				  &curr_buff[*curr_buff_cnt], nbytes);
 		*curr_buff_cnt += nbytes;
-- 
2.50.1.windows.1