On Sat, Aug 07, 2021 at 11:06:39AM +0800, Chen Li wrote:
> 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);
You forgot to include something that actually calls this function.
Anyway, there should be no need for this. If you're trying to convert a SHA-256
hash value to a string, just use the %*phN printk format specifier which
converts bytes to hex.
- Eric
