lib/crypto: sha1: Add SHA-1 library functions

Add a library interface for SHA-1, following the SHA-2 one.  As was the
case with SHA-2, this will be useful for various in-kernel users.  The
crypto_shash interface will be reimplemented on top of it as well.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250712232329.818226-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

1 files changed, 60 insertions, 0 deletions

diff --git a/include/crypto/sha1.h b/include/crypto/sha1.h
index d853d3b93169..387f6123a05e 100644
--- a/include/crypto/sha1.h
+++ b/include/crypto/sha1.h
@@ -36,4 +36,64 @@ struct sha1_state {
 void sha1_init_raw(__u32 *buf);
 void sha1_transform(__u32 *digest, const char *data, __u32 *W);
 
+/* State for the SHA-1 compression function */
+struct sha1_block_state {
+	u32 h[SHA1_DIGEST_SIZE / 4];
+};
+
+/**
+ * struct sha1_ctx - Context for hashing a message with SHA-1
+ * @state: the compression function state
+ * @bytecount: number of bytes processed so far
+ * @buf: partial block buffer; bytecount % SHA1_BLOCK_SIZE bytes are valid
+ */
+struct sha1_ctx {
+	struct sha1_block_state state;
+	u64 bytecount;
+	u8 buf[SHA1_BLOCK_SIZE];
+};
+
+/**
+ * sha1_init() - Initialize a SHA-1 context for a new message
+ * @ctx: the context to initialize
+ *
+ * If you don't need incremental computation, consider sha1() instead.
+ *
+ * Context: Any context.
+ */
+void sha1_init(struct sha1_ctx *ctx);
+
+/**
+ * sha1_update() - Update a SHA-1 context with message data
+ * @ctx: the context to update; must have been initialized
+ * @data: the message data
+ * @len: the data length in bytes
+ *
+ * This can be called any number of times.
+ *
+ * Context: Any context.
+ */
+void sha1_update(struct sha1_ctx *ctx, const u8 *data, size_t len);
+
+/**
+ * sha1_final() - Finish computing a SHA-1 message digest
+ * @ctx: the context to finalize; must have been initialized
+ * @out: (output) the resulting SHA-1 message digest
+ *
+ * After finishing, this zeroizes @ctx.  So the caller does not need to do it.
+ *
+ * Context: Any context.
+ */
+void sha1_final(struct sha1_ctx *ctx, u8 out[SHA1_DIGEST_SIZE]);
+
+/**
+ * sha1() - Compute SHA-1 message digest in one shot
+ * @data: the message data
+ * @len: the data length in bytes
+ * @out: (output) the resulting SHA-1 message digest
+ *
+ * Context: Any context.
+ */
+void sha1(const u8 *data, size_t len, u8 out[SHA1_DIGEST_SIZE]);
+
 #endif /* _CRYPTO_SHA1_H */