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[tor-commits] [tor/master] Use a custom Base64 encoder with more control over the output format.
commit 196499da73afa5c8000154aafe36c10b9ee43901
Author: Yawning Angel <yawning@xxxxxxxxxxxxxxx>
Date: Fri Apr 10 11:25:08 2015 +0000
Use a custom Base64 encoder with more control over the output format.
---
changes/feature15652 | 4 ++
src/common/crypto.c | 171 ++++++++++++++++++++++++++++++++++++++------
src/common/crypto.h | 5 +-
src/common/crypto_format.c | 2 +-
src/or/connection.c | 19 +----
src/or/dirvote.c | 5 +-
src/or/rendclient.c | 7 +-
src/or/rendcommon.c | 3 +-
src/or/rendservice.c | 10 ++-
src/or/router.c | 2 +-
src/or/routerparse.c | 3 +-
src/test/test_crypto.c | 36 +++++++++-
src/tools/tor-gencert.c | 6 +-
13 files changed, 214 insertions(+), 59 deletions(-)
diff --git a/changes/feature15652 b/changes/feature15652
index d11b76f..61d2b22 100644
--- a/changes/feature15652
+++ b/changes/feature15652
@@ -1,3 +1,7 @@
+ o Code simplifications and refactoring:
+ - Use our own Base64 encoder instead of OpenSSL's, to allow more control
+ over the output. Part of ticket 15652.
+
o Removed code:
- Remove `USE_OPENSSL_BASE64` and the corresponding fallback code and
always use the internal Base64 decoder. The internal decoder has been
diff --git a/src/common/crypto.c b/src/common/crypto.c
index c7e015b..2cb1c39 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -2426,36 +2426,161 @@ smartlist_shuffle(smartlist_t *sl)
}
}
+#define BASE64_OPENSSL_LINELEN 64
+
+/** Return the Base64 encoded size of <b>srclen</b> bytes of data in
+ * bytes.
+ *
+ * If <b>flags</b>&BASE64_ENCODE_MULTILINE is true, return the size
+ * of the encoded output as multiline output (64 character, `\n' terminated
+ * lines).
+ */
+size_t
+base64_encode_size(size_t srclen, int flags)
+{
+ size_t enclen;
+ tor_assert(srclen < INT_MAX);
+
+ if (srclen == 0)
+ return 0;
+
+ enclen = ((srclen - 1) / 3) * 4 + 4;
+ if (flags & BASE64_ENCODE_MULTILINE) {
+ size_t remainder = enclen % BASE64_OPENSSL_LINELEN;
+ enclen += enclen / BASE64_OPENSSL_LINELEN;
+ if (remainder)
+ enclen++;
+ }
+ tor_assert(enclen < INT_MAX && enclen > srclen);
+ return enclen;
+}
+
+/** Internal table mapping 6 bit values to the Base64 alphabet. */
+static const char base64_encode_table[64] = {
+ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+ 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+ 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
+ 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+ 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
+ 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
+ 'w', 'x', 'y', 'z', '0', '1', '2', '3',
+ '4', '5', '6', '7', '8', '9', '+', '/'
+};
+
/** Base64 encode <b>srclen</b> bytes of data from <b>src</b>. Write
* the result into <b>dest</b>, if it will fit within <b>destlen</b>
- * bytes. Return the number of bytes written on success; -1 if
+ * bytes. Return the number of bytes written on success; -1 if
* destlen is too short, or other failure.
+ *
+ * If <b>flags</b>&BASE64_ENCODE_MULTILINE is true, return encoded
+ * output in multiline format (64 character, `\n' terminated lines).
*/
int
-base64_encode(char *dest, size_t destlen, const char *src, size_t srclen)
-{
- /* FFFF we might want to rewrite this along the lines of base64_decode, if
- * it ever shows up in the profile. */
- EVP_ENCODE_CTX ctx;
- int len, ret;
- tor_assert(srclen < INT_MAX);
+base64_encode(char *dest, size_t destlen, const char *src, size_t srclen,
+ int flags)
+{
+ const unsigned char *usrc = (unsigned char *)src;
+ const unsigned char *eous = usrc + srclen;
+ char *d = dest;
+ uint32_t n = 0;
+ size_t linelen = 0;
+ size_t enclen;
+ int n_idx = 0;
+
+ if (!src || !dest)
+ return -1;
- /* 48 bytes of input -> 64 bytes of output plus newline.
- Plus one more byte, in case I'm wrong.
- */
- if (destlen < ((srclen/48)+1)*66)
+ /* Ensure that there is sufficient space, including the NUL. */
+ enclen = base64_encode_size(srclen, flags);
+ if (destlen < enclen + 1)
return -1;
if (destlen > SIZE_T_CEILING)
return -1;
- EVP_EncodeInit(&ctx);
- EVP_EncodeUpdate(&ctx, (unsigned char*)dest, &len,
- (unsigned char*)src, (int)srclen);
- EVP_EncodeFinal(&ctx, (unsigned char*)(dest+len), &ret);
- ret += len;
- return ret;
+ memset(dest, 0, enclen);
+
+ /* XXX/Yawning: If this ends up being too slow, this can be sped up
+ * by separating the multiline format case and the normal case, and
+ * processing 48 bytes of input at a time when newlines are desired.
+ */
+#define ENCODE_CHAR(ch) \
+ STMT_BEGIN \
+ *d++ = ch; \
+ if (flags & BASE64_ENCODE_MULTILINE) { \
+ if (++linelen % BASE64_OPENSSL_LINELEN == 0) { \
+ linelen = 0; \
+ *d++ = '\n'; \
+ } \
+ } \
+ STMT_END
+
+#define ENCODE_N(idx) \
+ ENCODE_CHAR(base64_encode_table[(n >> ((3 - idx) * 6)) & 0x3f])
+
+#define ENCODE_PAD() ENCODE_CHAR('=')
+
+ /* Iterate over all the bytes in src. Each one will add 8 bits to the
+ * value we're encoding. Accumulate bits in <b>n</b>, and whenever we
+ * have 24 bits, batch them into 4 bytes and flush those bytes to dest.
+ */
+ for ( ; usrc < eous; ++usrc) {
+ n = (n << 8) | *usrc;
+ if ((++n_idx) == 3) {
+ ENCODE_N(0);
+ ENCODE_N(1);
+ ENCODE_N(2);
+ ENCODE_N(3);
+ n_idx = 0;
+ n = 0;
+ }
+ }
+ switch (n_idx) {
+ case 0:
+ /* 0 leftover bits, no pading to add. */
+ break;
+ case 1:
+ /* 8 leftover bits, pad to 12 bits, write the 2 6-bit values followed
+ * by 2 padding characters.
+ */
+ n <<= 4;
+ ENCODE_N(2);
+ ENCODE_N(3);
+ ENCODE_PAD();
+ ENCODE_PAD();
+ break;
+ case 2:
+ /* 16 leftover bits, pad to 18 bits, write the 3 6-bit values followed
+ * by 1 padding character.
+ */
+ n <<= 2;
+ ENCODE_N(1);
+ ENCODE_N(2);
+ ENCODE_N(3);
+ ENCODE_PAD();
+ break;
+ default:
+ /* Something went catastrophically wrong. */
+ tor_fragile_assert();
+ return -1;
+ }
+
+#undef ENCODE_N
+#undef ENCODE_PAD
+#undef ENCODE_CHAR
+
+ /* Multiline output always includes at least one newline. */
+ if (flags & BASE64_ENCODE_MULTILINE && linelen != 0)
+ *d++ = '\n';
+
+ tor_assert(d - dest == (ptrdiff_t)enclen);
+
+ *d++ = '\0'; /* NUL terminate the output. */
+
+ return enclen;
}
+#undef BASE64_OPENSSL_LINELEN
+
/** @{ */
/** Special values used for the base64_decode_table */
#define X 255
@@ -2576,13 +2701,13 @@ base64_decode(char *dest, size_t destlen, const char *src, size_t srclen)
#undef PAD
/** Base64 encode DIGEST_LINE bytes from <b>digest</b>, remove the trailing =
- * and newline characters, and store the nul-terminated result in the first
+ * characters, and store the nul-terminated result in the first
* BASE64_DIGEST_LEN+1 bytes of <b>d64</b>. */
int
digest_to_base64(char *d64, const char *digest)
{
char buf[256];
- base64_encode(buf, sizeof(buf), digest, DIGEST_LEN);
+ base64_encode(buf, sizeof(buf), digest, DIGEST_LEN, 0);
buf[BASE64_DIGEST_LEN] = '\0';
memcpy(d64, buf, BASE64_DIGEST_LEN+1);
return 0;
@@ -2601,13 +2726,13 @@ digest_from_base64(char *digest, const char *d64)
}
/** Base64 encode DIGEST256_LINE bytes from <b>digest</b>, remove the
- * trailing = and newline characters, and store the nul-terminated result in
- * the first BASE64_DIGEST256_LEN+1 bytes of <b>d64</b>. */
+ * trailing = characters, and store the nul-terminated result in the first
+ * BASE64_DIGEST256_LEN+1 bytes of <b>d64</b>. */
int
digest256_to_base64(char *d64, const char *digest)
{
char buf[256];
- base64_encode(buf, sizeof(buf), digest, DIGEST256_LEN);
+ base64_encode(buf, sizeof(buf), digest, DIGEST256_LEN, 0);
buf[BASE64_DIGEST256_LEN] = '\0';
memcpy(d64, buf, BASE64_DIGEST256_LEN+1);
return 0;
diff --git a/src/common/crypto.h b/src/common/crypto.h
index 440ff23..2061ec3 100644
--- a/src/common/crypto.h
+++ b/src/common/crypto.h
@@ -267,7 +267,10 @@ struct smartlist_t;
void *smartlist_choose(const struct smartlist_t *sl);
void smartlist_shuffle(struct smartlist_t *sl);
-int base64_encode(char *dest, size_t destlen, const char *src, size_t srclen);
+#define BASE64_ENCODE_MULTILINE 1
+size_t base64_encode_size(size_t srclen, int flags);
+int base64_encode(char *dest, size_t destlen, const char *src, size_t srclen,
+ int flags);
int base64_decode(char *dest, size_t destlen, const char *src, size_t srclen);
/** Characters that can appear (case-insensitively) in a base32 encoding. */
#define BASE32_CHARS "abcdefghijklmnopqrstuvwxyz234567"
diff --git a/src/common/crypto_format.c b/src/common/crypto_format.c
index 00e0e9e..35a7854 100644
--- a/src/common/crypto_format.c
+++ b/src/common/crypto_format.c
@@ -19,7 +19,7 @@ curve25519_public_to_base64(char *output,
{
char buf[128];
base64_encode(buf, sizeof(buf),
- (const char*)pkey->public_key, CURVE25519_PUBKEY_LEN);
+ (const char*)pkey->public_key, CURVE25519_PUBKEY_LEN, 0);
buf[CURVE25519_BASE64_PADDED_LEN] = '\0';
memcpy(output, buf, CURVE25519_BASE64_PADDED_LEN+1);
return 0;
diff --git a/src/or/connection.c b/src/or/connection.c
index 369df67..5610815 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -4440,25 +4440,12 @@ alloc_http_authenticator(const char *authenticator)
/* an authenticator in Basic authentication
* is just the string "username:password" */
const size_t authenticator_length = strlen(authenticator);
- /* The base64_encode function needs a minimum buffer length
- * of 66 bytes. */
- const size_t base64_authenticator_length = (authenticator_length/48+1)*66;
+ const size_t base64_authenticator_length =
+ base64_encode_size(authenticator_length, 0) + 1;
char *base64_authenticator = tor_malloc(base64_authenticator_length);
if (base64_encode(base64_authenticator, base64_authenticator_length,
- authenticator, authenticator_length) < 0) {
+ authenticator, authenticator_length, 0) < 0) {
tor_free(base64_authenticator); /* free and set to null */
- } else {
- int i = 0, j = 0;
- ssize_t len = strlen(base64_authenticator);
-
- /* remove all newline occurrences within the string */
- for (i=0; i < len; ++i) {
- if ('\n' != base64_authenticator[i]) {
- base64_authenticator[j] = base64_authenticator[i];
- ++j;
- }
- }
- base64_authenticator[j]='\0';
}
return base64_authenticator;
}
diff --git a/src/or/dirvote.c b/src/or/dirvote.c
index 7a5154d..3009026 100644
--- a/src/or/dirvote.c
+++ b/src/or/dirvote.c
@@ -2244,7 +2244,8 @@ networkstatus_format_signatures(networkstatus_t *consensus,
for_detached_signatures ? flavor_name : "",
digest_name, id, sk);
}
- base64_encode(buf, sizeof(buf), sig->signature, sig->signature_len);
+ base64_encode(buf, sizeof(buf), sig->signature, sig->signature_len,
+ BASE64_ENCODE_MULTILINE);
strlcat(buf, "-----END SIGNATURE-----\n", sizeof(buf));
smartlist_add(elements, tor_strdup(buf));
} SMARTLIST_FOREACH_END(sig);
@@ -3459,7 +3460,7 @@ dirvote_create_microdescriptor(const routerinfo_t *ri, int consensus_method)
char kbuf[128];
base64_encode(kbuf, sizeof(kbuf),
(const char*)ri->onion_curve25519_pkey->public_key,
- CURVE25519_PUBKEY_LEN);
+ CURVE25519_PUBKEY_LEN, BASE64_ENCODE_MULTILINE);
smartlist_add_asprintf(chunks, "ntor-onion-key %s", kbuf);
}
diff --git a/src/or/rendclient.c b/src/or/rendclient.c
index 162e0ac..de66b6d 100644
--- a/src/or/rendclient.c
+++ b/src/or/rendclient.c
@@ -685,12 +685,13 @@ directory_get_from_hs_dir(const char *desc_id, const rend_data_t *rend_query)
if (rend_query->auth_type != REND_NO_AUTH) {
if (base64_encode(descriptor_cookie_base64,
sizeof(descriptor_cookie_base64),
- rend_query->descriptor_cookie, REND_DESC_COOKIE_LEN)<0) {
+ rend_query->descriptor_cookie, REND_DESC_COOKIE_LEN,
+ 0)<0) {
log_warn(LD_BUG, "Could not base64-encode descriptor cookie.");
return 0;
}
- /* Remove == signs and newline. */
- descriptor_cookie_base64[strlen(descriptor_cookie_base64)-3] = '\0';
+ /* Remove == signs. */
+ descriptor_cookie_base64[strlen(descriptor_cookie_base64)-2] = '\0';
} else {
strlcpy(descriptor_cookie_base64, "(none)",
sizeof(descriptor_cookie_base64));
diff --git a/src/or/rendcommon.c b/src/or/rendcommon.c
index 5711f9e..435602f 100644
--- a/src/or/rendcommon.c
+++ b/src/or/rendcommon.c
@@ -529,7 +529,8 @@ rend_encode_v2_descriptors(smartlist_t *descs_out,
}
/* Base64-encode introduction points. */
ipos_base64 = tor_calloc(ipos_len, 2);
- if (base64_encode(ipos_base64, ipos_len * 2, ipos, ipos_len)<0) {
+ if (base64_encode(ipos_base64, ipos_len * 2, ipos, ipos_len,
+ BASE64_ENCODE_MULTILINE)<0) {
log_warn(LD_REND, "Could not encode introduction point string to "
"base64. length=%d", (int)ipos_len);
tor_free(ipos_base64);
diff --git a/src/or/rendservice.c b/src/or/rendservice.c
index c1c0c46..0a41ed2 100644
--- a/src/or/rendservice.c
+++ b/src/or/rendservice.c
@@ -941,7 +941,7 @@ rend_service_load_auth_keys(rend_service_t *s, const char *hfname)
}
if (base64_encode(desc_cook_out, 3*REND_DESC_COOKIE_LEN_BASE64+1,
client->descriptor_cookie,
- REND_DESC_COOKIE_LEN) < 0) {
+ REND_DESC_COOKIE_LEN, 0) < 0) {
log_warn(LD_BUG, "Could not base64-encode descriptor cookie.");
goto err;
}
@@ -968,7 +968,6 @@ rend_service_load_auth_keys(rend_service_t *s, const char *hfname)
client->client_key = prkey;
}
/* Add entry to client_keys file. */
- desc_cook_out[strlen(desc_cook_out)-1] = '\0'; /* Remove newline. */
written = tor_snprintf(buf, sizeof(buf),
"client-name %s\ndescriptor-cookie %s\n",
client->client_name, desc_cook_out);
@@ -1023,12 +1022,11 @@ rend_service_load_auth_keys(rend_service_t *s, const char *hfname)
((int)s->auth_type - 1) << 4;
if (base64_encode(desc_cook_out, 3*REND_DESC_COOKIE_LEN_BASE64+1,
extended_desc_cookie,
- REND_DESC_COOKIE_LEN+1) < 0) {
+ REND_DESC_COOKIE_LEN+1, 0) < 0) {
log_warn(LD_BUG, "Could not base64-encode descriptor cookie.");
goto err;
}
- desc_cook_out[strlen(desc_cook_out)-3] = '\0'; /* Remove A= and
- newline. */
+ desc_cook_out[strlen(desc_cook_out)-2] = '\0'; /* Remove A=. */
tor_snprintf(buf, sizeof(buf),"%s.onion %s # client: %s\n",
service_id, desc_cook_out, client->client_name);
}
@@ -1124,7 +1122,7 @@ rend_check_authorization(rend_service_t *service,
if (!auth_client) {
char descriptor_cookie_base64[3*REND_DESC_COOKIE_LEN_BASE64];
base64_encode(descriptor_cookie_base64, sizeof(descriptor_cookie_base64),
- descriptor_cookie, REND_DESC_COOKIE_LEN);
+ descriptor_cookie, REND_DESC_COOKIE_LEN, 0);
log_info(LD_REND, "No authorization found for descriptor cookie '%s'! "
"Dropping cell!",
descriptor_cookie_base64);
diff --git a/src/or/router.c b/src/or/router.c
index 2ddaa89..b803ba5 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -2424,7 +2424,7 @@ router_dump_router_to_string(routerinfo_t *router,
char kbuf[128];
base64_encode(kbuf, sizeof(kbuf),
(const char *)router->onion_curve25519_pkey->public_key,
- CURVE25519_PUBKEY_LEN);
+ CURVE25519_PUBKEY_LEN, BASE64_ENCODE_MULTILINE);
smartlist_add_asprintf(chunks, "ntor-onion-key %s", kbuf);
}
diff --git a/src/or/routerparse.c b/src/or/routerparse.c
index fd3971c..b9a36a3 100644
--- a/src/or/routerparse.c
+++ b/src/or/routerparse.c
@@ -664,7 +664,8 @@ router_get_dirobj_signature(const char *digest,
goto truncated;
i = strlen(buf);
- if (base64_encode(buf+i, buf_len-i, signature, siglen) < 0) {
+ if (base64_encode(buf+i, buf_len-i, signature, siglen,
+ BASE64_ENCODE_MULTILINE) < 0) {
log_warn(LD_BUG,"couldn't base64-encode signature");
goto err;
}
diff --git a/src/test/test_crypto.c b/src/test/test_crypto.c
index e9fb8bf..299373e 100644
--- a/src/test/test_crypto.c
+++ b/src/test/test_crypto.c
@@ -14,6 +14,8 @@
#include "crypto_ed25519.h"
#include "ed25519_vectors.inc"
+#include <openssl/evp.h>
+
extern const char AUTHORITY_SIGNKEY_3[];
extern const char AUTHORITY_SIGNKEY_A_DIGEST[];
extern const char AUTHORITY_SIGNKEY_A_DIGEST256[];
@@ -601,6 +603,22 @@ test_crypto_digests(void *arg)
crypto_pk_free(k);
}
+/** Encode src into dest with OpenSSL's EVP Encode interface, returning the
+ * length of the encoded data in bytes.
+ */
+static int
+base64_encode_evp(char *dest, char *src, size_t srclen)
+{
+ const unsigned char *s = (unsigned char*)src;
+ EVP_ENCODE_CTX ctx;
+ int len, ret;
+
+ EVP_EncodeInit(&ctx);
+ EVP_EncodeUpdate(&ctx, (unsigned char *)dest, &len, s, srclen);
+ EVP_EncodeFinal(&ctx, (unsigned char *)(dest + len), &ret);
+ return ret+ len;
+}
+
/** Run unit tests for misc crypto formatting functionality (base64, base32,
* fingerprints, etc) */
static void
@@ -618,7 +636,7 @@ test_crypto_formats(void *arg)
/* Base64 tests */
memset(data1, 6, 1024);
for (idx = 0; idx < 10; ++idx) {
- i = base64_encode(data2, 1024, data1, idx);
+ i = base64_encode(data2, 1024, data1, idx, 0);
tt_int_op(i, OP_GE, 0);
j = base64_decode(data3, 1024, data2, i);
tt_int_op(j,OP_EQ, idx);
@@ -628,7 +646,7 @@ test_crypto_formats(void *arg)
strlcpy(data1, "Test string that contains 35 chars.", 1024);
strlcat(data1, " 2nd string that contains 35 chars.", 1024);
- i = base64_encode(data2, 1024, data1, 71);
+ i = base64_encode(data2, 1024, data1, 71, 0);
tt_int_op(i, OP_GE, 0);
j = base64_decode(data3, 1024, data2, i);
tt_int_op(j,OP_EQ, 71);
@@ -647,6 +665,20 @@ test_crypto_formats(void *arg)
tt_assert(digest_from_base64(data3, "###") < 0);
+ for (i = 0; i < 256; i++) {
+ /* Test the multiline format Base64 encoder with 0 .. 256 bytes of
+ * output against OpenSSL.
+ */
+ const size_t enclen = base64_encode_size(i, BASE64_ENCODE_MULTILINE);
+ data1[i] = i;
+ j = base64_encode(data2, 1024, data1, i, BASE64_ENCODE_MULTILINE);
+ tt_int_op(j, OP_EQ, enclen);
+ j = base64_encode_evp(data3, data1, i);
+ tt_int_op(j, OP_EQ, enclen);
+ tt_mem_op(data2, OP_EQ, data3, enclen);
+ tt_int_op(j, OP_EQ, strlen(data2));
+ }
+
/* Encoding SHA256 */
crypto_rand(data2, DIGEST256_LEN);
memset(data2, 100, 1024);
diff --git a/src/tools/tor-gencert.c b/src/tools/tor-gencert.c
index 5ae1556..c0cab7e 100644
--- a/src/tools/tor-gencert.c
+++ b/src/tools/tor-gencert.c
@@ -486,7 +486,8 @@ generate_certificate(void)
EVP_PKEY_get1_RSA(signing_key),
RSA_PKCS1_PADDING);
signed_len = strlen(buf);
- base64_encode(buf+signed_len, sizeof(buf)-signed_len, signature, r);
+ base64_encode(buf+signed_len, sizeof(buf)-signed_len, signature, r,
+ BASE64_ENCODE_MULTILINE);
strlcat(buf,
"-----END ID SIGNATURE-----\n"
@@ -501,7 +502,8 @@ generate_certificate(void)
RSA_PKCS1_PADDING);
strlcat(buf, "-----BEGIN SIGNATURE-----\n", sizeof(buf));
signed_len = strlen(buf);
- base64_encode(buf+signed_len, sizeof(buf)-signed_len, signature, r);
+ base64_encode(buf+signed_len, sizeof(buf)-signed_len, signature, r,
+ BASE64_ENCODE_MULTILINE);
strlcat(buf, "-----END SIGNATURE-----\n", sizeof(buf));
if (!(f = fopen(certificate_file, "w"))) {
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