MINOR: sample: Add digest and hmac converters

Make the digest and HMAC function of OpenSSL accessible to the user via
converters. They can be used to sign and validate content.

Reviewed-by: Tim Duesterhus <tim@bastelstu.be>

doc/configuration.txt

@@ -14499,6 +14499,13 @@ debug([<prefix][,<destination>])
   Example:
     tcp-request connection track-sc0 src,debug(track-sc)
 
+digest(<algorithm>)
+  Converts a binary input sample to a message digest. The result is a binary
+  sample. The <algorithm> must be an OpenSSL message digest name (e.g. sha256).
+
+  Please note that this converter is only available when haproxy has been
+  compiled with USE_OPENSSL.
+
 div(<value>)
   Divides the input value of type signed integer by <value>, and returns the
   result as an signed integer. If <value> is null, the largest unsigned
@@ -14559,6 +14566,15 @@ htonl
   this converter is used, the input integer value is first casted to an
   unsigned 32-bit integer.
 
+hmac(<algorithm>, <key>)
+  Converts a binary input sample to a message authentication code with the given
+  key. The result is a binary sample. The <algorithm> must be one of the
+  registered OpenSSL message digest names (e.g. sha256). The <key> parameter must
+  be base64 encoded and can either be a string or a variable.
+
+  Please note that this converter is only available when haproxy has been
+  compiled with USE_OPENSSL.
+
 http_date([<offset],[<unit>])
   Converts an integer supposed to contain a date since epoch to a string
   representing this date in a format suitable for use in HTTP header fields. If

reg-tests/converter/digest.vtc

@@ -0,0 +1,57 @@
+varnishtest "digest converter Test"
+
+#REQUIRE_VERSION=2.2
+#REQUIRE_OPTION=OPENSSL
+
+feature ignore_unknown_macro
+
+server s1 {
+	rxreq
+	txresp
+} -repeat 2 -start
+
+haproxy h1 -conf {
+    defaults
+	mode http
+	timeout connect 1s
+	timeout client  1s
+	timeout server  1s
+
+    frontend fe
+	bind "fd@${fe}"
+
+	#### requests
+	http-request  set-var(txn.hash) req.hdr(hash)
+
+	http-response set-header SHA1   "%[var(txn.hash),digest(sha1),hex,lower]"
+	http-response set-header SHA224   "%[var(txn.hash),digest(sha224),hex,lower]"
+	http-response set-header SHA256   "%[var(txn.hash),digest(sha256),hex,lower]"
+	http-response set-header SHA384   "%[var(txn.hash),digest(sha384),hex,lower]"
+	http-response set-header SHA512   "%[var(txn.hash),digest(sha512),hex,lower]"
+
+	default_backend be
+
+    backend be
+	server s1 ${s1_addr}:${s1_port}
+} -start
+
+client c1 -connect ${h1_fe_sock} {
+	txreq -url "/" \
+	  -hdr "Hash: 1"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.sha1 == "356a192b7913b04c54574d18c28d46e6395428ab"
+	expect resp.http.sha224 == "e25388fde8290dc286a6164fa2d97e551b53498dcbf7bc378eb1f178"
+	expect resp.http.sha256 == "6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b"
+	expect resp.http.sha384 == "47f05d367b0c32e438fb63e6cf4a5f35c2aa2f90dc7543f8a41a0f95ce8a40a313ab5cf36134a2068c4c969cb50db776"
+	expect resp.http.sha512 == "4dff4ea340f0a823f15d3f4f01ab62eae0e5da579ccb851f8db9dfe84c58b2b37b89903a740e1ee172da793a6e79d560e5f7f9bd058a12a280433ed6fa46510a"
+	txreq -url "/" \
+	  -hdr "Hash: 2"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.sha1 == "da4b9237bacccdf19c0760cab7aec4a8359010b0"
+	expect resp.http.sha224 == "58b2aaa0bfae7acc021b3260e941117b529b2e69de878fd7d45c61a9"
+	expect resp.http.sha256 == "d4735e3a265e16eee03f59718b9b5d03019c07d8b6c51f90da3a666eec13ab35"
+	expect resp.http.sha384 == "d063457705d66d6f016e4cdd747db3af8d70ebfd36badd63de6c8ca4a9d8bfb5d874e7fbd750aa804dcaddae7eeef51e"
+	expect resp.http.sha512 == "40b244112641dd78dd4f93b6c9190dd46e0099194d5a44257b7efad6ef9ff4683da1eda0244448cb343aa688f5d3efd7314dafe580ac0bcbf115aeca9e8dc114"
+} -run

reg-tests/converter/hmac.vtc

@@ -0,0 +1,55 @@
+varnishtest "HMAC converter Test"
+
+#REQUIRE_VERSION=2.2
+#REQUIRE_OPTION=OPENSSL
+
+feature ignore_unknown_macro
+
+server s1 {
+	rxreq
+	txresp
+} -repeat 2 -start
+
+haproxy h1 -conf {
+    defaults
+	mode http
+	timeout connect 1s
+	timeout client  1s
+	timeout server  1s
+
+    frontend fe
+	bind "fd@${fe}"
+
+	#### requests
+	http-request  set-var(txn.hash) req.hdr(hash)
+	http-request  set-var(txn.key) str(my_super_secret_long_key),base64
+
+	http-response set-header SHA1-short   "%[var(txn.hash),hmac(sha1,a2V5),hex,lower]"
+	http-response set-header SHA1-long   "%[var(txn.hash),hmac(sha1,txn.key),hex,lower]"
+	http-response set-header SHA256-short   "%[var(txn.hash),hmac(sha256,a2V5),hex,lower]"
+	http-response set-header SHA256-long   "%[var(txn.hash),hmac(sha256,txn.key),hex,lower]"
+
+	default_backend be
+
+    backend be
+	server s1 ${s1_addr}:${s1_port}
+} -start
+
+client c1 -connect ${h1_fe_sock} {
+	txreq -url "/" \
+	  -hdr "Hash: 1"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.sha1-short == "e23feb105f9622241bf23db1638cd2b4208b1f53"
+	expect resp.http.sha1-long == "87b10ddcf39e26f6bd7c3b0e38e0125997b255be"
+	expect resp.http.sha256-short == "6da91fb91517be1f5cdcf3af91d7d40c717dd638a306157606fb2e584f7ae926"
+	expect resp.http.sha256-long == "2fb3de6a462c54d1803f946b52202f3a8cd46548ffb3f789b4ac11a4361ffef2"
+	txreq -url "/" \
+	  -hdr "Hash: 2"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.sha1-short == "311219c4a80c5ef81b1cee5505236c1d0ab1922c"
+	expect resp.http.sha1-long == "c5758af565ba4b87b3db49c8b32d4a94d430cb78"
+	expect resp.http.sha256-short == "ae7b3ee87b8c9214f714df1c2042c7a985b9d711e9938a063937ad1636775a88"
+	expect resp.http.sha256-long == "c073191a2ebf29f510444b92c187d62199d84b58f58dceeadb91994c170a9a16"
+} -run

src/sample.c

@@ -1654,7 +1654,6 @@ static int sample_conv_sha2(const struct arg *arg_p, struct sample *smp, void *p
 	return 1;
 }
 
-#if (HA_OPENSSL_VERSION_NUMBER >= 0x1000100fL)
 static inline int sample_conv_var2smp_str(const struct arg *arg, struct sample *smp)
 {
 	switch (arg->type) {
@@ -1675,6 +1674,7 @@ static inline int sample_conv_var2smp_str(const struct arg *arg, struct sample *
 	}
 }
 
+#if (HA_OPENSSL_VERSION_NUMBER >= 0x1000100fL)
 static int check_aes_gcm(struct arg *args, struct sample_conv *conv,
 						  const char *file, int line, char **err)
 {
@@ -1786,6 +1786,95 @@ err:
 }
 #endif /* HA_OPENSSL_VERSION_NUMBER */
 
+static int check_crypto_digest(struct arg *args, struct sample_conv *conv,
+						  const char *file, int line, char **err)
+{
+	const EVP_MD *evp = EVP_get_digestbyname(args[0].data.str.area);
+
+	if (evp)
+		return 1;
+
+	memprintf(err, "algorithm must be a valid OpenSSL message digest name.");
+	return 0;
+}
+
+static int sample_conv_crypto_digest(const struct arg *args, struct sample *smp, void *private)
+{
+	struct buffer *trash = get_trash_chunk();
+	unsigned char *md = (unsigned char*) trash->area;
+	unsigned int md_len = trash->size;
+	EVP_MD_CTX *ctx = EVP_MD_CTX_new();
+	const EVP_MD *evp = EVP_get_digestbyname(args[0].data.str.area);
+
+	if (!ctx)
+		return 0;
+
+	if (!EVP_DigestInit_ex(ctx, evp, NULL) ||
+	    !EVP_DigestUpdate(ctx, smp->data.u.str.area, smp->data.u.str.data) ||
+	    !EVP_DigestFinal_ex(ctx, md, &md_len)) {
+		EVP_MD_CTX_free(ctx);
+		return 0;
+	}
+
+	EVP_MD_CTX_free(ctx);
+
+	trash->data = md_len;
+	smp->data.u.str = *trash;
+	smp->data.type = SMP_T_BIN;
+	smp->flags &= ~SMP_F_CONST;
+	return 1;
+}
+
+static int check_crypto_hmac(struct arg *args, struct sample_conv *conv,
+						  const char *file, int line, char **err)
+{
+	if (!check_crypto_digest(args, conv, file, line, err))
+		return 0;
+
+	vars_check_arg(&args[1], NULL);
+	return 1;
+}
+
+static int sample_conv_crypto_hmac(const struct arg *args, struct sample *smp, void *private)
+{
+	struct sample key;
+	struct buffer *trash, *key_trash;
+	unsigned char *md;
+	unsigned int md_len;
+	const EVP_MD *evp = EVP_get_digestbyname(args[0].data.str.area);
+	int dec_size;
+
+	smp_set_owner(&key, smp->px, smp->sess, smp->strm, smp->opt);
+	if (!sample_conv_var2smp_str(&args[1], &key))
+		return 0;
+
+	trash = get_trash_chunk();
+	key_trash = alloc_trash_chunk();
+	if (!key_trash)
+		return 0;
+
+	dec_size = base64dec(key.data.u.str.area, key.data.u.str.data, key_trash->area, key_trash->size);
+	if (dec_size < 0)
+		goto err;
+
+	md = (unsigned char*) trash->area;
+	md_len = trash->size;
+	if (!HMAC(evp, key_trash->area, dec_size, (const unsigned char*) smp->data.u.str.area, smp->data.u.str.data, md, &md_len))
+		goto err;
+
+	free_trash_chunk(key_trash);
+
+	trash->data = md_len;
+	smp->data.u.str = *trash;
+	smp->data.type = SMP_T_BIN;
+	smp->flags &= ~SMP_F_CONST;
+	return 1;
+
+err:
+	free_trash_chunk(key_trash);
+	return 0;
+}
+
 #endif /* USE_OPENSSL */
 
 static int sample_conv_bin2hex(const struct arg *arg_p, struct sample *smp, void *private)
@@ -3632,6 +3721,8 @@ static struct sample_conv_kw_list sample_conv_kws = {ILH, {
 #if (HA_OPENSSL_VERSION_NUMBER >= 0x1000100fL)
 	{ "aes_gcm_dec", sample_conv_aes_gcm_dec,   ARG4(4,SINT,STR,STR,STR), check_aes_gcm,       SMP_T_BIN, SMP_T_BIN },
 #endif
+	{ "digest",      sample_conv_crypto_digest, ARG1(1,STR),              check_crypto_digest, SMP_T_BIN, SMP_T_BIN },
+	{ "hmac",        sample_conv_crypto_hmac,   ARG2(2,STR,STR),          check_crypto_hmac,   SMP_T_BIN, SMP_T_BIN },
 #endif
 	{ "concat", sample_conv_concat,    ARG3(1,STR,STR,STR), smp_check_concat, SMP_T_STR,  SMP_T_STR },
 	{ "strcmp", sample_conv_strcmp,    ARG1(1,STR), smp_check_strcmp, SMP_T_STR,  SMP_T_SINT },