From: Guus Sliepen Date: Tue, 28 May 2013 11:39:15 +0000 (+0200) Subject: Improve base64 encoding/decoding, add URL-safe variant. X-Git-Tag: release-1.1pre8~41 X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=commitdiff_plain;h=c3d357af6c73d538f7cbcaca293ebbca666d3a82 Improve base64 encoding/decoding, add URL-safe variant. b64decode() now returns length 0 when an invalid character was encountered. --- diff --git a/src/protocol_key.c b/src/protocol_key.c index af103c62..0eeddb86 100644 --- a/src/protocol_key.c +++ b/src/protocol_key.c @@ -158,11 +158,12 @@ static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, in logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name); char buf[MAX_STRING_SIZE]; - if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) { + int len; + + if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) { logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data"); return true; } - int len = b64decode(buf, buf, strlen(buf)); char label[25 + strlen(from->name) + strlen(myself->name)]; snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name); @@ -182,11 +183,11 @@ static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, in } char buf[MAX_STRING_SIZE]; - if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) { + int len; + if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) { logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS", from->name, from->hostname, "invalid SPTPS data"); return true; } - int len = b64decode(buf, buf, strlen(buf)); sptps_receive_data(&from->sptps, buf, len); return true; } @@ -375,7 +376,7 @@ bool ans_key_h(connection_t *c, const char *request) { char buf[strlen(key)]; int len = b64decode(key, buf, strlen(key)); - if(!sptps_receive_data(&from->sptps, buf, len)) + if(!len || !sptps_receive_data(&from->sptps, buf, len)) logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname); if(from->status.validkey) { diff --git a/src/utils.c b/src/utils.c index aefec8c8..dca88d6d 100644 --- a/src/utils.c +++ b/src/utils.c @@ -24,7 +24,26 @@ #include "utils.h" static const char hexadecimals[] = "0123456789ABCDEF"; -static const char base64imals[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +static const char base64_original[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +static const char base64_urlsafe[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"; +static const char base64_decode[256] = { + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, + -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, + 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, + -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +}; static int charhex2bin(char c) { if(isdigit(c)) @@ -33,19 +52,6 @@ static int charhex2bin(char c) { return toupper(c) - 'A' + 10; } -static int charb64decode(char c) { - if(c >= 'a') - return c - 'a' + 26; - else if(c >= 'A') - return c - 'A'; - else if(c >= '0') - return c - '0' + 52; - else if(c == '+') - return 62; - else - return 63; -} - int hex2bin(const char *src, char *dst, int length) { int i; for(i = 0; i < length && isxdigit(src[i * 2]) && isxdigit(src[i * 2 + 1]); i++) @@ -68,8 +74,10 @@ int b64decode(const char *src, char *dst, int length) { unsigned char *udst = (unsigned char *)dst; for(i = 0; i < length / 3 * 4 && src[i]; i++) { - triplet |= charb64decode(src[i]) << (6 * (i & 3)); + triplet |= base64_decode[src[i] & 0xff] << (6 * (i & 3)); if((i & 3) == 3) { + if(triplet & 0xff000000U) + return 0; udst[0] = triplet & 0xff; triplet >>= 8; udst[1] = triplet & 0xff; triplet >>= 8; udst[2] = triplet; @@ -77,6 +85,8 @@ int b64decode(const char *src, char *dst, int length) { udst += 3; } } + if(triplet & 0xff000000U) + return 0; if((i & 3) == 3) { udst[0] = triplet & 0xff; triplet >>= 8; udst[1] = triplet & 0xff; @@ -89,7 +99,7 @@ int b64decode(const char *src, char *dst, int length) { } } -int b64encode(const char *src, char *dst, int length) { +static int b64encode_internal(const char *src, char *dst, int length, const char *alphabet) { uint32_t triplet; const unsigned char *usrc = (unsigned char *)src; int si = length / 3 * 3; @@ -98,16 +108,16 @@ int b64encode(const char *src, char *dst, int length) { switch(length % 3) { case 2: triplet = usrc[si] | usrc[si + 1] << 8; - dst[di] = base64imals[triplet & 63]; triplet >>= 6; - dst[di + 1] = base64imals[triplet & 63]; triplet >>= 6; - dst[di + 2] = base64imals[triplet]; + dst[di] = alphabet[triplet & 63]; triplet >>= 6; + dst[di + 1] = alphabet[triplet & 63]; triplet >>= 6; + dst[di + 2] = alphabet[triplet]; dst[di + 3] = 0; length = di + 2; break; case 1: triplet = usrc[si]; - dst[di] = base64imals[triplet & 63]; triplet >>= 6; - dst[di + 1] = base64imals[triplet]; + dst[di] = alphabet[triplet & 63]; triplet >>= 6; + dst[di + 1] = alphabet[triplet]; dst[di + 2] = 0; length = di + 1; break; @@ -121,15 +131,23 @@ int b64encode(const char *src, char *dst, int length) { di -= 4; si -= 3; triplet = usrc[si] | usrc[si + 1] << 8 | usrc[si + 2] << 16; - dst[di] = base64imals[triplet & 63]; triplet >>= 6; - dst[di + 1] = base64imals[triplet & 63]; triplet >>= 6; - dst[di + 2] = base64imals[triplet & 63]; triplet >>= 6; - dst[di + 3] = base64imals[triplet]; + dst[di] = alphabet[triplet & 63]; triplet >>= 6; + dst[di + 1] = alphabet[triplet & 63]; triplet >>= 6; + dst[di + 2] = alphabet[triplet & 63]; triplet >>= 6; + dst[di + 3] = alphabet[triplet]; } return length; } +int b64encode(const char *src, char *dst, int length) { + return b64encode_internal(src, dst, length, base64_original); +} + +int b64encode_urlsafe(const char *src, char *dst, int length) { + return b64encode_internal(src, dst, length, base64_urlsafe); +} + #if defined(HAVE_MINGW) || defined(HAVE_CYGWIN) #ifdef HAVE_CYGWIN #include diff --git a/src/utils.h b/src/utils.h index 04e478af..f3272910 100644 --- a/src/utils.h +++ b/src/utils.h @@ -25,6 +25,7 @@ extern int hex2bin(const char *src, char *dst, int length); extern int bin2hex(const char *src, char *dst, int length); extern int b64encode(const char *src, char *dst, int length); +extern int b64encode_urlsafe(const char *src, char *dst, int length); extern int b64decode(const char *src, char *dst, int length); #ifdef HAVE_MINGW