/* Provenance: openssl/openssl use_proxy (fixed).
 * repo: openssl/openssl
 * commit: 654dc11d23468a74fc8ea4672b702dd3feb7be4b
 * parent: a79c4ce559c6a3a8fd4109e9f33c1185d5bf2def
 * commit_url: https://github.com/openssl/openssl/commit/654dc11d23468a74fc8ea4672b702dd3feb7be4b
 * cve: CVE-2025-9232
 * license: Apache-2.0
 * function: use_proxy
 * relpath: crypto/http/http_lib.c
 */

static int use_proxy(const char *no_proxy, const char *server)
{
    size_t sl;
    const char *found = NULL;
    char host[NI_MAXHOST];

    if (!ossl_assert(server != NULL))
        return 0;
    sl = strlen(server);
    if (sl >= 2 && sl < sizeof(host) + 2 && server[0] == '[' && server[sl - 1] == ']') {
        /* strip leading '[' and trailing ']' from escaped IPv6 address */
        sl -= 2;
        strncpy(host, server + 1, sl);
        host[sl] = '\0';
        server = host;
    }

    /*
     * using environment variable names, both lowercase and uppercase variants,
     * compatible with other HTTP client implementations like wget, curl and git
     */
    if (no_proxy == NULL)
        no_proxy = ossl_safe_getenv("no_proxy");
    if (no_proxy == NULL)
        no_proxy = ossl_safe_getenv(OPENSSL_NO_PROXY);

    if (no_proxy != NULL)
        found = strstr(no_proxy, server);
    while (found != NULL
           && ((found != no_proxy && !ossl_isspace(found[-1]) && found[-1] != ',')
               || (found[sl] != '\0' && !ossl_isspace(found[sl]) && found[sl] != ',')))
        found = strstr(found + 1, server);
    return found == NULL;
}