Merge pull request #41 from bwhacks/security-fixes

[odhcp6c.git] / src / script.c

diff --git a/src/script.c b/src/script.c
index f272c190afdaa3eb07a20c6c8c9a001557b717de..357933105d35d56f5718fbad56b30595dbe80557 100644 (file)
--- a/src/script.c
+++ b/src/script.c
@@ -118,9 +118,10 @@ static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
        char *buf = realloc(NULL, len + buf_len + 2);
        memcpy(buf, name, buf_len);
        buf[buf_len++] = '=';
-       int l = 1;
-       while (l > 0 && fqdn < fqdn_end) {
-               l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
+       while (fqdn < fqdn_end) {
+               int l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
+               if (l <= 0)
+                       break;
                fqdn += l;
                buf_len += strlen(&buf[buf_len]);
                buf[buf_len++] = ' ';
@@ -156,7 +157,10 @@ static void entry_to_env(const char *name, const void *data, size_t len, enum en
 {
        size_t buf_len = strlen(name);
        const struct odhcp6c_entry *e = data;
-       char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * 144);
+       // Worst case: ENTRY_PREFIX with iaid != 1 and exclusion
+       const size_t max_entry_len = (INET6_ADDRSTRLEN-1 + 5 + 22 + 15 + 10 +
+                                     INET6_ADDRSTRLEN-1 + 11 + 1);
+       char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * max_entry_len);
        memcpy(buf, name, buf_len);
        buf[buf_len++] = '=';
 
@@ -164,28 +168,34 @@ static void entry_to_env(const char *name, const void *data, size_t len, enum en
                inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
                buf_len += strlen(&buf[buf_len]);
                if (type != ENTRY_HOST) {
-                       buf_len += snprintf(&buf[buf_len], 6, "/%"PRIu16, e[i].length);
+                       snprintf(&buf[buf_len], 6, "/%"PRIu16, e[i].length);
+                       buf += strlen(&buf[buf_len]);
                        if (type == ENTRY_ROUTE) {
                                buf[buf_len++] = ',';
                                if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
                                        inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
                                        buf_len += strlen(&buf[buf_len]);
                                }
-                               buf_len += snprintf(&buf[buf_len], 24, ",%u", e[i].valid);
-                               buf_len += snprintf(&buf[buf_len], 12, ",%u", e[i].priority);
+                               snprintf(&buf[buf_len], 23, ",%u,%u", e[i].valid, e[i].priority);
+                               buf += strlen(&buf[buf_len]);
                        } else {
-                               buf_len += snprintf(&buf[buf_len], 24, ",%u,%u", e[i].preferred, e[i].valid);
+                               snprintf(&buf[buf_len], 23, ",%u,%u", e[i].preferred, e[i].valid);
+                               buf += strlen(&buf[buf_len]);
                        }
 
-                       if (type == ENTRY_PREFIX && ntohl(e[i].iaid) != 1)
-                               buf_len += snprintf(&buf[buf_len], 16, ",class=%08x", ntohl(e[i].iaid));
+                       if (type == ENTRY_PREFIX && ntohl(e[i].iaid) != 1) {
+                               snprintf(&buf[buf_len], 16, ",class=%08x", ntohl(e[i].iaid));
+                               buf += strlen(&buf[buf_len]);
+                       }
 
                        if (type == ENTRY_PREFIX && e[i].priority) {
                                // priority and router are abused for prefix exclusion
-                               buf_len += snprintf(&buf[buf_len], 12, ",excluded=");
+                               snprintf(&buf[buf_len], 11, ",excluded=");
+                               buf_len += strlen(&buf[buf_len]);
                                inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
                                buf_len += strlen(&buf[buf_len]);
-                               buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
+                               snprintf(&buf[buf_len], 12, "/%u", e[i].priority);
+                               buf_len += strlen(&buf[buf_len]);
                        }
                }
                buf[buf_len++] = ' ';
@@ -217,7 +227,7 @@ static void search_to_env(const char *name, const uint8_t *start, size_t len)
 
 static void int_to_env(const char *name, int value)
 {
-       size_t len = 12 + strlen(name);
+       size_t len = 13 + strlen(name);
        char *buf = realloc(NULL, len);
        snprintf(buf, len, "%s=%d", name, value);
        putenv(buf);
@@ -272,7 +282,8 @@ static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len
                        size_t prefix6len = rule->prefix6_len;
                        prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 
-                       if (olen < sizeof(struct dhcpv6_s46_rule) + prefix6len)
+                       if (prefix6len > sizeof(in6) ||
+                           olen < sizeof(struct dhcpv6_s46_rule) + prefix6len)
                                continue;
 
                        memcpy(&in6, rule->ipv6_prefix, prefix6len);
@@ -301,7 +312,8 @@ static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len
                                        size_t prefix6len = dmr->dmr_prefix6_len;
                                        prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 
-                                       if (olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len)
+                                       if (prefix6len > sizeof(in6) ||
+                                           olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len)
                                                continue;
 
                                        memcpy(&in6, dmr->dmr_ipv6_prefix, prefix6len);
@@ -320,7 +332,8 @@ static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len
                        size_t prefix6len = bind->bindprefix6_len;
                        prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 
-                       if (olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len)
+                       if (prefix6len > sizeof(in6) ||
+                           olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len)
                                continue;
 
                        memcpy(&in6, bind->bind_ipv6_prefix, prefix6len);