Merge pull request #566 from teg/util-base64-2

util: add base64 handling

src/basic/util.c

@@ -916,32 +916,218 @@ char *hexmem(const void *p, size_t l) {
         return r;
 }
 
-void *unhexmem(const char *p, size_t l) {
-        uint8_t *r, *z;
+int unhexmem(const char *p, size_t l, void **mem, size_t *len) {
+        _cleanup_free_ uint8_t *r = NULL;
+        uint8_t *z;
         const char *x;
 
+        assert(mem);
+        assert(len);
         assert(p);
 
         z = r = malloc((l + 1) / 2 + 1);
         if (!r)
-                return NULL;
+                return -ENOMEM;
 
         for (x = p; x < p + l; x += 2) {
                 int a, b;
 
                 a = unhexchar(x[0]);
-                if (x+1 < p + l)
+                if (a < 0)
+                        return a;
+                else if (x+1 < p + l) {
                         b = unhexchar(x[1]);
-                else
+                        if (b < 0)
+                                return b;
+                } else
                         b = 0;
 
                 *(z++) = (uint8_t) a << 4 | (uint8_t) b;
         }
 
+        *z = 0;
+
+        *mem = r;
+        r = NULL;
+        *len = (l + 1) / 2;
+
+        return 0;
+}
+
+/* https://tools.ietf.org/html/rfc4648#section-4 */
+char base64char(int x) {
+        static const char table[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                                      "abcdefghijklmnopqrstuvwxyz"
+                                      "0123456789+/";
+        return table[x & 63];
+}
+
+int unbase64char(char c) {
+        unsigned offset;
+
+        if (c >= 'A' && c <= 'Z')
+                return c - 'A';
+
+        offset = 'Z' - 'A' + 1;
+
+        if (c >= 'a' && c <= 'z')
+                return c - 'a' + offset;
+
+        offset += 'z' - 'a' + 1;
+
+        if (c >= '0' && c <= '9')
+                return c - '0' + offset;
+
+        offset += '9' - '0' + 1;
+
+        if (c == '+')
+                return offset;
+
+        offset ++;
+
+        if (c == '/')
+                return offset;
+
+        return -EINVAL;
+}
+
+char *base64mem(const void *p, size_t l) {
+        char *r, *z;
+        const uint8_t *x;
+
+        /* three input bytes makes four output bytes, padding is added so we must round up */
+        z = r = malloc(4 * (l + 2) / 3 + 1);
+        if (!r)
+                return NULL;
+
+        for (x = p; x < (const uint8_t*) p + (l / 3) * 3; x += 3) {
+                /* x[0] == XXXXXXXX; x[1] == YYYYYYYY; x[2] == ZZZZZZZZ */
+                *(z++) = base64char(x[0] >> 2);                    /* 00XXXXXX */
+                *(z++) = base64char((x[0] & 3) << 4 | x[1] >> 4);  /* 00XXYYYY */
+                *(z++) = base64char((x[1] & 15) << 2 | x[2] >> 6); /* 00YYYYZZ */
+                *(z++) = base64char(x[2] & 63);                    /* 00ZZZZZZ */
+        }
+
+        switch (l % 3) {
+        case 2:
+                *(z++) = base64char(x[0] >> 2);                   /* 00XXXXXX */
+                *(z++) = base64char((x[0] & 3) << 4 | x[1] >> 4); /* 00XXYYYY */
+                *(z++) = base64char((x[1] & 15) << 2);            /* 00YYYY00 */
+                *(z++) = '=';
+
+                break;
+        case 1:
+                *(z++) = base64char(x[0] >> 2);        /* 00XXXXXX */
+                *(z++) = base64char((x[0] & 3) << 4);  /* 00XX0000 */
+                *(z++) = '=';
+                *(z++) = '=';
+
+                break;
+        }
+
         *z = 0;
         return r;
 }
 
+int unbase64mem(const char *p, size_t l, void **mem, size_t *_len) {
+        _cleanup_free_ uint8_t *t = NULL;
+        int a, b, c, d;
+        uint8_t *r, *z;
+        const char *x;
+        size_t len;
+
+        assert(p);
+
+        /* padding ensures any base63 input has input divisible by 4 */
+        if (l % 4 != 0)
+                return -EINVAL;
+
+        /* strip the padding */
+        if (l > 0 && p[l - 1] == '=')
+                l --;
+        if (l > 0 && p[l - 1] == '=')
+                l --;
+
+        /* a group of four input bytes needs three output bytes, in case of
+           padding we need to add two or three extra bytes */
+        len = (l / 4) * 3 + (l % 4 ? (l % 4) - 1 : 0);
+
+        z = r = malloc(len + 1);
+        if (!r)
+                return -ENOMEM;
+
+        for (x = p; x < p + (l / 4) * 4; x += 4) {
+                /* a == 00XXXXXX; b == 00YYYYYY; c == 00ZZZZZZ; d == 00WWWWWW */
+                a = unbase64char(x[0]);
+                if (a < 0)
+                        return -EINVAL;
+
+                b = unbase64char(x[1]);
+                if (b < 0)
+                        return -EINVAL;
+
+                c = unbase64char(x[2]);
+                if (c < 0)
+                        return -EINVAL;
+
+                d = unbase64char(x[3]);
+                if (d < 0)
+                        return -EINVAL;
+
+                *(z++) = (uint8_t) a << 2 | (uint8_t) b >> 4; /* XXXXXXYY */
+                *(z++) = (uint8_t) b << 4 | (uint8_t) c >> 2; /* YYYYZZZZ */
+                *(z++) = (uint8_t) c << 6 | (uint8_t) d;      /* ZZWWWWWW */
+        }
+
+        switch (l % 4) {
+        case 3:
+                a = unbase64char(x[0]);
+                if (a < 0)
+                        return -EINVAL;
+
+                b = unbase64char(x[1]);
+                if (b < 0)
+                        return -EINVAL;
+
+                c = unbase64char(x[2]);
+                if (c < 0)
+                        return -EINVAL;
+
+                /* c == 00ZZZZ00 */
+                if (c & 3)
+                        return -EINVAL;
+
+                *(z++) = (uint8_t) a << 2 | (uint8_t) b >> 4; /* XXXXXXYY */
+                *(z++) = (uint8_t) b << 4 | (uint8_t) c >> 2; /* YYYYZZZZ */
+
+                break;
+        case 2:
+                a = unbase64char(x[0]);
+                if (a < 0)
+                        return -EINVAL;
+
+                b = unbase64char(x[1]);
+                if (b < 0)
+                        return -EINVAL;
+
+                /* b == 00YY0000 */
+                if (b & 15)
+                        return -EINVAL;
+
+                *(z++) = (uint8_t) a << 2 | (uint8_t) (b >> 4); /* XXXXXXYY */
+
+                break;
+        }
+
+        *z = 0;
+
+        *mem = r;
+        r = NULL;
+        *_len = len;
+
+        return 0;
+}
+
 char octchar(int x) {
         return '0' + (x & 7);
 }

src/basic/util.h

@@ -240,6 +240,8 @@ char octchar(int x) _const_;
 int unoctchar(char c) _const_;
 char decchar(int x) _const_;
 int undecchar(char c) _const_;
+char base64char(int x) _const_;
+int unbase64char(char c) _const_;
 
 char *cescape(const char *s);
 size_t cescape_char(char c, char *buf);
@@ -614,7 +616,10 @@ static inline void *mempset(void *s, int c, size_t n) {
 }
 
 char *hexmem(const void *p, size_t l);
-void *unhexmem(const char *p, size_t l);
+int unhexmem(const char *p, size_t l, void **mem, size_t *len);
+
+char *base64mem(const void *p, size_t l);
+int unbase64mem(const char *p, size_t l, void **mem, size_t *len);
 
 char *strextend(char **x, ...) _sentinel_;
 char *strrep(const char *s, unsigned n);

src/libsystemd-network/sd-dhcp-lease.c

@@ -811,13 +811,12 @@ int sd_dhcp_lease_load(sd_dhcp_lease **ret, const char *lease_file) {
         }
 
         if (client_id_hex) {
-                if (strlen (client_id_hex) % 2)
+                if (strlen(client_id_hex) % 2)
                         return -EINVAL;
 
-                lease->client_id = unhexmem (client_id_hex, strlen (client_id_hex));
-                if (!lease->client_id)
-                        return -ENOMEM;
-                lease->client_id_len = strlen (client_id_hex) / 2;
+                r = unhexmem(client_id_hex, strlen(client_id_hex), (void**) &lease->client_id, &lease->client_id_len);
+                if (r < 0)
+                        return r;
         }
 
         *ret = lease;

src/libsystemd/sd-bus/bus-socket.c

@@ -264,6 +264,8 @@ static bool line_begins(const char *s, size_t m, const char *word) {
 
 static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
         _cleanup_free_ char *token = NULL;
+        size_t len;
+        int r;
 
         if (!b->anonymous_auth)
                 return 0;
@@ -276,11 +278,12 @@ static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
 
         if (l % 2 != 0)
                 return 0;
-        token = unhexmem(p, l);
-        if (!token)
-                return -ENOMEM;
 
-        if (memchr(token, 0, l/2))
+        r = unhexmem(p, l, (void **) &token, &len);
+        if (r < 0)
+                return 0;
+
+        if (memchr(token, 0, len))
                 return 0;
 
         return !!utf8_is_valid(token);
@@ -288,6 +291,7 @@ static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
 
 static int verify_external_token(sd_bus *b, const char *p, size_t l) {
         _cleanup_free_ char *token = NULL;
+        size_t len;
         uid_t u;
         int r;
 
@@ -307,11 +311,11 @@ static int verify_external_token(sd_bus *b, const char *p, size_t l) {
         if (l % 2 != 0)
                 return 0;
 
-        token = unhexmem(p, l);
-        if (!token)
-                return -ENOMEM;
+        r = unhexmem(p, l, (void**) &token, &len);
+        if (r < 0)
+                return 0;
 
-        if (memchr(token, 0, l/2))
+        if (memchr(token, 0, len))
                 return 0;
 
         r = parse_uid(token, &u);

src/test/test-util.c

@@ -390,6 +390,24 @@ static void test_unhexchar(void) {
         assert_se(unhexchar('0') == 0x0);
 }
 
+static void test_base64char(void) {
+        assert_se(base64char(0) == 'A');
+        assert_se(base64char(26) == 'a');
+        assert_se(base64char(63) == '/');
+}
+
+static void test_unbase64char(void) {
+        assert_se(unbase64char('A') == 0);
+        assert_se(unbase64char('Z') == 25);
+        assert_se(unbase64char('a') == 26);
+        assert_se(unbase64char('z') == 51);
+        assert_se(unbase64char('0') == 52);
+        assert_se(unbase64char('9') == 61);
+        assert_se(unbase64char('+') == 62);
+        assert_se(unbase64char('/') == 63);
+        assert_se(unbase64char('=') == -EINVAL);
+}
+
 static void test_octchar(void) {
         assert_se(octchar(00) == '0');
         assert_se(octchar(07) == '7');
@@ -410,6 +428,108 @@ static void test_undecchar(void) {
         assert_se(undecchar('9') == 9);
 }
 
+static void test_unhexmem(void) {
+        const char *hex = "efa214921";
+        const char *hex_invalid = "efa214921o";
+        _cleanup_free_ char *hex2 = NULL;
+        _cleanup_free_ void *mem = NULL;
+        size_t len;
+
+        assert_se(unhexmem(hex, strlen(hex), &mem, &len) == 0);
+        assert_se(unhexmem(hex, strlen(hex) + 1, &mem, &len) == -EINVAL);
+        assert_se(unhexmem(hex_invalid, strlen(hex_invalid), &mem, &len) == -EINVAL);
+
+        assert_se((hex2 = hexmem(mem, len)));
+
+        free(mem);
+
+        assert_se(memcmp(hex, hex2, strlen(hex)) == 0);
+
+        free(hex2);
+
+        assert_se(unhexmem(hex, strlen(hex) - 1, &mem, &len) == 0);
+        assert_se((hex2 = hexmem(mem, len)));
+        assert_se(memcmp(hex, hex2, strlen(hex) - 1) == 0);
+}
+
+/* https://tools.ietf.org/html/rfc4648#section-10 */
+static void test_base64mem(void) {
+        char *b64;
+
+        b64 = base64mem("", strlen(""));
+        assert_se(b64);
+        assert_se(streq(b64, ""));
+        free(b64);
+
+        b64 = base64mem("f", strlen("f"));
+        assert_se(b64);
+        assert_se(streq(b64, "Zg=="));
+        free(b64);
+
+        b64 = base64mem("fo", strlen("fo"));
+        assert_se(b64);
+        assert_se(streq(b64, "Zm8="));
+        free(b64);
+
+        b64 = base64mem("foo", strlen("foo"));
+        assert_se(b64);
+        assert_se(streq(b64, "Zm9v"));
+        free(b64);
+
+        b64 = base64mem("foob", strlen("foob"));
+        assert_se(b64);
+        assert_se(streq(b64, "Zm9vYg=="));
+        free(b64);
+
+        b64 = base64mem("fooba", strlen("fooba"));
+        assert_se(b64);
+        assert_se(streq(b64, "Zm9vYmE="));
+        free(b64);
+
+        b64 = base64mem("foobar", strlen("foobar"));
+        assert_se(b64);
+        assert_se(streq(b64, "Zm9vYmFy"));
+        free(b64);
+}
+
+static void test_unbase64mem(void) {
+        void *mem;
+        size_t len;
+
+        assert_se(unbase64mem("", strlen(""), &mem, &len) == 0);
+        assert_se(streq(strndupa(mem, len), ""));
+        free(mem);
+
+        assert_se(unbase64mem("Zg==", strlen("Zg=="), &mem, &len) == 0);
+        assert_se(streq(strndupa(mem, len), "f"));
+        free(mem);
+
+        assert_se(unbase64mem("Zm8=", strlen("Zm8="), &mem, &len) == 0);
+        assert_se(streq(strndupa(mem, len), "fo"));
+        free(mem);
+
+        assert_se(unbase64mem("Zm9v", strlen("Zm9v"), &mem, &len) == 0);
+        assert_se(streq(strndupa(mem, len), "foo"));
+        free(mem);
+
+        assert_se(unbase64mem("Zm9vYg==", strlen("Zm9vYg=="), &mem, &len) == 0);
+        assert_se(streq(strndupa(mem, len), "foob"));
+        free(mem);
+
+        assert_se(unbase64mem("Zm9vYmE=", strlen("Zm9vYmE="), &mem, &len) == 0);
+        assert_se(streq(strndupa(mem, len), "fooba"));
+        free(mem);
+
+        assert_se(unbase64mem("Zm9vYmFy", strlen("Zm9vYmFy"), &mem, &len) == 0);
+        assert_se(streq(strndupa(mem, len), "foobar"));
+        free(mem);
+
+        assert_se(unbase64mem("A", strlen("A"), &mem, &len) == -EINVAL);
+        assert_se(unbase64mem("A====", strlen("A===="), &mem, &len) == -EINVAL);
+        assert_se(unbase64mem("AAB==", strlen("AAB=="), &mem, &len) == -EINVAL);
+        assert_se(unbase64mem("AAAB=", strlen("AAAB="), &mem, &len) == -EINVAL);
+}
+
 static void test_cescape(void) {
         _cleanup_free_ char *escaped;
 
@@ -1804,10 +1924,15 @@ int main(int argc, char *argv[]) {
         test_in_charset();
         test_hexchar();
         test_unhexchar();
+        test_base64char();
+        test_unbase64char();
         test_octchar();
         test_unoctchar();
         test_decchar();
         test_undecchar();
+        test_unhexmem();
+        test_base64mem();
+        test_unbase64mem();
         test_cescape();
         test_cunescape();
         test_foreach_word();