[PATCH] crypto: lib/sha256 - add sha256_value function

[Chen Li]

Add a function sha256_value() which accepts a string and store SHA256 hash
of this string into dest.

Signed-off-by: Chen Li <chenli@xxxxxxxxxxxxx>
---
 include/crypto/sha2.h |  1 +
 lib/crypto/sha256.c   | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/include/crypto/sha2.h b/include/crypto/sha2.h
index 2838f529f31e..ce17954cab38 100644
--- a/include/crypto/sha2.h
+++ b/include/crypto/sha2.h
@@ -115,6 +115,7 @@ static inline void sha256_init(struct sha256_state *sctx)
 void sha256_update(struct sha256_state *sctx, const u8 *data, unsigned int len);
 void sha256_final(struct sha256_state *sctx, u8 *out);
 void sha256(const u8 *data, unsigned int len, u8 *out);
+int  sha256_value(u8 **dest, const u8 *src);
 
 static inline void sha224_init(struct sha256_state *sctx)
 {
diff --git a/lib/crypto/sha256.c b/lib/crypto/sha256.c
index 72a4b0b1df28..ce1de7a3e32e 100644
--- a/lib/crypto/sha256.c
+++ b/lib/crypto/sha256.c
@@ -13,6 +13,8 @@
 
 #include <linux/bitops.h>
 #include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/string.h>
 #include <crypto/sha2.h>
@@ -206,4 +208,25 @@ void sha256(const u8 *data, unsigned int len, u8 *out)
 }
 EXPORT_SYMBOL(sha256);
 
+int sha256_value(u8 **dest, const u8 *src)
+{
+	u8 out[SHA256_DIGEST_SIZE];
+	int i, k;
+	unsigned char hex[2];
+
+	*dest = kvmalloc(sizeof(u8) * (SHA256_BLOCK_SIZE + 1), GFP_KERNEL);
+	if (ZERO_OR_NULL_PTR(*dest))
+		return -ENOMEM;
+	sha256(src, strlen(src), out);
+
+	for (i = 0, k = 0; i < SHA256_DIGEST_SIZE; i++) {
+		sprintf(hex, "%02x", out[i]);
+		(*dest)[k++] = hex[0];
+		(*dest)[k++] = hex[1];
+	}
+	(*dest)[k] = '\0';
+	return 0;
+}
+EXPORT_SYMBOL(sha256_value);
+
 MODULE_LICENSE("GPL");
-- 
2.32.0.93.g670b81a890