crypto: hash - annotate algorithms taking optional key

We need to consistently enforce that keyed hashes cannot be used without
setting the key.  To do this we need a reliable way to determine whether
a given hash algorithm is keyed or not.  AF_ALG currently does this by
checking for the presence of a ->setkey() method.  However, this is
actually slightly broken because the CRC-32 algorithms implement
->setkey() but can also be used without a key.  (The CRC-32 "key" is not
actually a cryptographic key but rather represents the initial state.
If not overridden, then a default initial state is used.)

Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which
indicates that the algorithm has a ->setkey() method, but it is not
required to be called.  Then set it on all the CRC-32 algorithms.

The same also applies to the Adler-32 implementation in Lustre.

Also, the cryptd and mcryptd templates have to pass through the flag
from their underlying algorithm.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/crypto/crc32-ce-glue.c

@@ -188,6 +188,7 @@ static struct shash_alg crc32_pmull_algs[] = { {
 	.base.cra_name		= "crc32",
 	.base.cra_driver_name	= "crc32-arm-ce",
 	.base.cra_priority	= 200,
+	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 	.base.cra_blocksize	= 1,
 	.base.cra_module	= THIS_MODULE,
 }, {
@@ -203,6 +204,7 @@ static struct shash_alg crc32_pmull_algs[] = { {
 	.base.cra_name		= "crc32c",
 	.base.cra_driver_name	= "crc32c-arm-ce",
 	.base.cra_priority	= 200,
+	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 	.base.cra_blocksize	= 1,
 	.base.cra_module	= THIS_MODULE,
 } };

arch/arm64/crypto/crc32-ce-glue.c

@@ -185,6 +185,7 @@ static struct shash_alg crc32_pmull_algs[] = { {
 	.base.cra_name		= "crc32",
 	.base.cra_driver_name	= "crc32-arm64-ce",
 	.base.cra_priority	= 200,
+	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 	.base.cra_blocksize	= 1,
 	.base.cra_module	= THIS_MODULE,
 }, {
@@ -200,6 +201,7 @@ static struct shash_alg crc32_pmull_algs[] = { {
 	.base.cra_name		= "crc32c",
 	.base.cra_driver_name	= "crc32c-arm64-ce",
 	.base.cra_priority	= 200,
+	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 	.base.cra_blocksize	= 1,
 	.base.cra_module	= THIS_MODULE,
 } };

arch/powerpc/crypto/crc32c-vpmsum_glue.c

@@ -141,6 +141,7 @@ static struct shash_alg alg = {
 		.cra_name		= "crc32c",
 		.cra_driver_name	= "crc32c-vpmsum",
 		.cra_priority		= 200,
+		.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(u32),
 		.cra_module		= THIS_MODULE,

arch/s390/crypto/crc32-vx.c

@@ -239,6 +239,7 @@ static struct shash_alg crc32_vx_algs[] = {
 			.cra_name	 = "crc32",
 			.cra_driver_name = "crc32-vx",
 			.cra_priority	 = 200,
+			.cra_flags	 = CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize	 = CRC32_BLOCK_SIZE,
 			.cra_ctxsize	 = sizeof(struct crc_ctx),
 			.cra_module	 = THIS_MODULE,
@@ -259,6 +260,7 @@ static struct shash_alg crc32_vx_algs[] = {
 			.cra_name	 = "crc32be",
 			.cra_driver_name = "crc32be-vx",
 			.cra_priority	 = 200,
+			.cra_flags	 = CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize	 = CRC32_BLOCK_SIZE,
 			.cra_ctxsize	 = sizeof(struct crc_ctx),
 			.cra_module	 = THIS_MODULE,
@@ -279,6 +281,7 @@ static struct shash_alg crc32_vx_algs[] = {
 			.cra_name	 = "crc32c",
 			.cra_driver_name = "crc32c-vx",
 			.cra_priority	 = 200,
+			.cra_flags	 = CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize	 = CRC32_BLOCK_SIZE,
 			.cra_ctxsize	 = sizeof(struct crc_ctx),
 			.cra_module	 = THIS_MODULE,

arch/sparc/crypto/crc32c_glue.c

@@ -133,6 +133,7 @@ static struct shash_alg alg = {
 		.cra_name		=	"crc32c",
 		.cra_driver_name	=	"crc32c-sparc64",
 		.cra_priority		=	SPARC_CR_OPCODE_PRIORITY,
+		.cra_flags		=	CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		=	CHKSUM_BLOCK_SIZE,
 		.cra_ctxsize		=	sizeof(u32),
 		.cra_alignmask		=	7,

arch/x86/crypto/crc32-pclmul_glue.c

@@ -162,6 +162,7 @@ static struct shash_alg alg = {
 			.cra_name		= "crc32",
 			.cra_driver_name	= "crc32-pclmul",
 			.cra_priority		= 200,
+			.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize		= CHKSUM_BLOCK_SIZE,
 			.cra_ctxsize		= sizeof(u32),
 			.cra_module		= THIS_MODULE,

arch/x86/crypto/crc32c-intel_glue.c

@@ -226,6 +226,7 @@ static struct shash_alg alg = {
 		.cra_name		=	"crc32c",
 		.cra_driver_name	=	"crc32c-intel",
 		.cra_priority		=	200,
+		.cra_flags		=	CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		=	CHKSUM_BLOCK_SIZE,
 		.cra_ctxsize		=	sizeof(u32),
 		.cra_module		=	THIS_MODULE,

crypto/crc32_generic.c

@@ -133,6 +133,7 @@ static struct shash_alg alg = {
 		.cra_name		= "crc32",
 		.cra_driver_name	= "crc32-generic",
 		.cra_priority		= 100,
+		.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(u32),
 		.cra_module		= THIS_MODULE,

crypto/crc32c_generic.c

@@ -146,6 +146,7 @@ static struct shash_alg alg = {
 		.cra_name		=	"crc32c",
 		.cra_driver_name	=	"crc32c-generic",
 		.cra_priority		=	100,
+		.cra_flags		=	CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		=	CHKSUM_BLOCK_SIZE,
 		.cra_alignmask		=	3,
 		.cra_ctxsize		=	sizeof(struct chksum_ctx),

crypto/cryptd.c

@@ -896,10 +896,9 @@ static int cryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb,
 	if (err)
 		goto out_free_inst;
 
-	type = CRYPTO_ALG_ASYNC;
+	inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC |
-	if (alg->cra_flags & CRYPTO_ALG_INTERNAL)
+		(alg->cra_flags & (CRYPTO_ALG_INTERNAL |
-		type |= CRYPTO_ALG_INTERNAL;
+				   CRYPTO_ALG_OPTIONAL_KEY));
-	inst->alg.halg.base.cra_flags = type;
 
 	inst->alg.halg.digestsize = salg->digestsize;
 	inst->alg.halg.statesize = salg->statesize;

crypto/mcryptd.c

@@ -516,10 +516,9 @@ static int mcryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb,
 	if (err)
 		goto out_free_inst;
 
-	type = CRYPTO_ALG_ASYNC;
+	inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC |
-	if (alg->cra_flags & CRYPTO_ALG_INTERNAL)
+		(alg->cra_flags & (CRYPTO_ALG_INTERNAL |
-		type |= CRYPTO_ALG_INTERNAL;
+				   CRYPTO_ALG_OPTIONAL_KEY));
-	inst->alg.halg.base.cra_flags = type;
 
 	inst->alg.halg.digestsize = halg->digestsize;
 	inst->alg.halg.statesize = halg->statesize;

drivers/crypto/bfin_crc.c

@@ -494,7 +494,8 @@ static struct ahash_alg algs = {
 		.cra_driver_name	= DRIVER_NAME,
 		.cra_priority		= 100,
 		.cra_flags		= CRYPTO_ALG_TYPE_AHASH |
-						CRYPTO_ALG_ASYNC,
+						CRYPTO_ALG_ASYNC |
+						CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(struct bfin_crypto_crc_ctx),
 		.cra_alignmask		= 3,

drivers/crypto/stm32/stm32_crc32.c

@@ -208,6 +208,7 @@ static struct shash_alg algs[] = {
 			.cra_name               = "crc32",
 			.cra_driver_name        = DRIVER_NAME,
 			.cra_priority           = 200,
+			.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
 			.cra_alignmask          = 3,
 			.cra_ctxsize            = sizeof(struct stm32_crc_ctx),
@@ -229,6 +230,7 @@ static struct shash_alg algs[] = {
 			.cra_name               = "crc32c",
 			.cra_driver_name        = DRIVER_NAME,
 			.cra_priority           = 200,
+			.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
 			.cra_alignmask          = 3,
 			.cra_ctxsize            = sizeof(struct stm32_crc_ctx),

drivers/staging/lustre/lnet/libcfs/linux/linux-crypto-adler.c

@@ -120,6 +120,7 @@ static struct shash_alg alg = {
 		.cra_name		= "adler32",
 		.cra_driver_name	= "adler32-zlib",
 		.cra_priority		= 100,
+		.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(u32),
 		.cra_module		= THIS_MODULE,

include/linux/crypto.h

@@ -106,6 +106,12 @@
  */
 #define CRYPTO_ALG_INTERNAL		0x00002000
 
+/*
+ * Set if the algorithm has a ->setkey() method but can be used without
+ * calling it first, i.e. there is a default key.
+ */
+#define CRYPTO_ALG_OPTIONAL_KEY		0x00004000
+
 /*
  * Transform masks and values (for crt_flags).
  */