hush: fix "true | func_with_return" not allowing return.
[oweals/busybox.git] / networking / httpd.c
index ba956318c9cef834baca54b465fd710a5fd3619f..079145757dcf265478d37bac87f2eb76e3cd4c8f 100644 (file)
  *
  */
  /* TODO: use TCP_CORK, parse_config() */
+//config:config HTTPD
+//config:      bool "httpd (32 kb)"
+//config:      default y
+//config:      help
+//config:      HTTP server.
+//config:
+//config:config FEATURE_HTTPD_RANGES
+//config:      bool "Support 'Ranges:' header"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      Makes httpd emit "Accept-Ranges: bytes" header and understand
+//config:      "Range: bytes=NNN-[MMM]" header. Allows for resuming interrupted
+//config:      downloads, seeking in multimedia players etc.
+//config:
+//config:config FEATURE_HTTPD_SETUID
+//config:      bool "Enable -u <user> option"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      This option allows the server to run as a specific user
+//config:      rather than defaulting to the user that starts the server.
+//config:      Use of this option requires special privileges to change to a
+//config:      different user.
+//config:
+//config:config FEATURE_HTTPD_BASIC_AUTH
+//config:      bool "Enable HTTP authentication"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      Utilizes password settings from /etc/httpd.conf for basic
+//config:      authentication on a per url basis.
+//config:      Example for httpd.conf file:
+//config:      /adm:toor:PaSsWd
+//config:
+//config:config FEATURE_HTTPD_AUTH_MD5
+//config:      bool "Support MD5-encrypted passwords in HTTP authentication"
+//config:      default y
+//config:      depends on FEATURE_HTTPD_BASIC_AUTH
+//config:      help
+//config:      Enables encrypted passwords, and wildcard user/passwords
+//config:      in httpd.conf file.
+//config:      User '*' means 'any system user name is ok',
+//config:      password of '*' means 'use system password for this user'
+//config:      Examples:
+//config:      /adm:toor:$1$P/eKnWXS$aI1aPGxT.dJD5SzqAKWrF0
+//config:      /adm:root:*
+//config:      /wiki:*:*
+//config:
+//config:config FEATURE_HTTPD_CGI
+//config:      bool "Support Common Gateway Interface (CGI)"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      This option allows scripts and executables to be invoked
+//config:      when specific URLs are requested.
+//config:
+//config:config FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
+//config:      bool "Support running scripts through an interpreter"
+//config:      default y
+//config:      depends on FEATURE_HTTPD_CGI
+//config:      help
+//config:      This option enables support for running scripts through an
+//config:      interpreter. Turn this on if you want PHP scripts to work
+//config:      properly. You need to supply an additional line in your
+//config:      httpd.conf file:
+//config:      *.php:/path/to/your/php
+//config:
+//config:config FEATURE_HTTPD_SET_REMOTE_PORT_TO_ENV
+//config:      bool "Set REMOTE_PORT environment variable for CGI"
+//config:      default y
+//config:      depends on FEATURE_HTTPD_CGI
+//config:      help
+//config:      Use of this option can assist scripts in generating
+//config:      references that contain a unique port number.
+//config:
+//config:config FEATURE_HTTPD_ENCODE_URL_STR
+//config:      bool "Enable -e option (useful for CGIs written as shell scripts)"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      This option allows html encoding of arbitrary strings for display
+//config:      by the browser. Output goes to stdout.
+//config:      For example, httpd -e "<Hello World>" produces
+//config:      "&#60Hello&#32World&#62".
+//config:
+//config:config FEATURE_HTTPD_ERROR_PAGES
+//config:      bool "Support custom error pages"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      This option allows you to define custom error pages in
+//config:      the configuration file instead of the default HTTP status
+//config:      error pages. For instance, if you add the line:
+//config:              E404:/path/e404.html
+//config:      in the config file, the server will respond the specified
+//config:      '/path/e404.html' file instead of the terse '404 NOT FOUND'
+//config:      message.
+//config:
+//config:config FEATURE_HTTPD_PROXY
+//config:      bool "Support reverse proxy"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      This option allows you to define URLs that will be forwarded
+//config:      to another HTTP server. To setup add the following line to the
+//config:      configuration file
+//config:              P:/url/:http://hostname[:port]/new/path/
+//config:      Then a request to /url/myfile will be forwarded to
+//config:      http://hostname[:port]/new/path/myfile.
+//config:
+//config:config FEATURE_HTTPD_GZIP
+//config:      bool "Support GZIP content encoding"
+//config:      default y
+//config:      depends on HTTPD
+//config:      help
+//config:      Makes httpd send files using GZIP content encoding if the
+//config:      client supports it and a pre-compressed <file>.gz exists.
+
+//applet:IF_HTTPD(APPLET(httpd, BB_DIR_USR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_HTTPD) += httpd.o
 
 //usage:#define httpd_trivial_usage
 //usage:       "[-ifv[v]]"
 //usage:     "\n       -d STRING       URL decode STRING"
 
 #include "libbb.h"
+#include "common_bufsiz.h"
 #if ENABLE_PAM
 /* PAM may include <locale.h>. We may need to undefine bbox's stub define: */
 # undef setlocale
 # include <security/pam_appl.h>
 # include <security/pam_misc.h>
 #endif
-#if ENABLE_FEATURE_HTTPD_USE_SENDFILE
+#if ENABLE_FEATURE_USE_SENDFILE
 # include <sys/sendfile.h>
 #endif
 /* amount of buffering in a pipe */
@@ -307,7 +430,8 @@ struct globals {
        Htaccess *script_i;     /* config script interpreters */
 #endif
        char *iobuf;            /* [IOBUF_SIZE] */
-#define hdr_buf bb_common_bufsiz1
+#define        hdr_buf bb_common_bufsiz1
+#define sizeof_hdr_buf COMMON_BUFSIZE
        char *hdr_ptr;
        int hdr_cnt;
 #if ENABLE_FEATURE_HTTPD_ERROR_PAGES
@@ -336,11 +460,6 @@ struct globals {
 #define ip_a_d            (G.ip_a_d           )
 #define g_realm           (G.g_realm          )
 #define remoteuser        (G.remoteuser       )
-#define referer           (G.referer          )
-#define user_agent        (G.user_agent       )
-#define host              (G.host             )
-#define http_accept       (G.http_accept      )
-#define http_accept_language (G.http_accept_language)
 #define file_size         (G.file_size        )
 #if ENABLE_FEATURE_HTTPD_RANGES
 #define range_start       (G.range_start      )
@@ -348,7 +467,7 @@ struct globals {
 #define range_len         (G.range_len        )
 #else
 enum {
-       range_start = 0,
+       range_start = -1,
        range_end = MAXINT(off_t) - 1,
        range_len = MAXINT(off_t),
 };
@@ -368,8 +487,10 @@ enum {
 # define content_gzip     0
 #endif
 #define INIT_G() do { \
+       setup_common_bufsiz(); \
        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
        IF_FEATURE_HTTPD_BASIC_AUTH(g_realm = "Web Server Authentication";) \
+       IF_FEATURE_HTTPD_RANGES(range_start = -1;) \
        bind_addr_or_port = "80"; \
        index_page = index_html; \
        file_size = -1; \
@@ -696,7 +817,7 @@ static void parse_conf(const char *path, int flag)
                                goto config_error;
                        }
                        *host_port++ = '\0';
-                       if (strncmp(host_port, "http://", 7) == 0)
+                       if (is_prefixed_with(host_port, "http://"))
                                host_port += 7;
                        if (*host_port == '\0') {
                                goto config_error;
@@ -795,9 +916,9 @@ static void parse_conf(const char *path, int flag)
                /* the line is not recognized */
  config_error:
                bb_error_msg("config error '%s' in '%s'", buf, filename);
-        } /* while (fgets) */
+       } /* while (fgets) */
 
-        fclose(f);
+       fclose(f);
 }
 
 #if ENABLE_FEATURE_HTTPD_ENCODE_URL_STR
@@ -922,16 +1043,16 @@ static void log_and_exit(void)
 static void send_headers(int responseNum)
 {
        static const char RFC1123FMT[] ALIGN1 = "%a, %d %b %Y %H:%M:%S GMT";
+       /* Fixed size 29-byte string. Example: Sun, 06 Nov 1994 08:49:37 GMT */
+       char date_str[40]; /* using a bit larger buffer to paranoia reasons */
 
        const char *responseString = "";
        const char *infoString = NULL;
-       const char *mime_type;
 #if ENABLE_FEATURE_HTTPD_ERROR_PAGES
        const char *error_page = NULL;
 #endif
        unsigned i;
        time_t timer = time(NULL);
-       char tmp_str[80];
        int len;
 
        for (i = 0; i < ARRAY_SIZE(http_response_type); i++) {
@@ -944,41 +1065,61 @@ static void send_headers(int responseNum)
                        break;
                }
        }
-       /* error message is HTML */
-       mime_type = responseNum == HTTP_OK ?
-                               found_mime_type : "text/html";
 
        if (verbose)
                bb_error_msg("response:%u", responseNum);
 
-       /* emit the current date */
-       strftime(tmp_str, sizeof(tmp_str), RFC1123FMT, gmtime(&timer));
+       /* We use sprintf, not snprintf (it's less code).
+        * iobuf[] is several kbytes long and all headers we generate
+        * always fit into those kbytes.
+        */
+
+       strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime(&timer));
        len = sprintf(iobuf,
-                       "HTTP/1.0 %d %s\r\nContent-type: %s\r\n"
-                       "Date: %s\r\nConnection: close\r\n",
-                       responseNum, responseString, mime_type, tmp_str);
+                       "HTTP/1.0 %d %s\r\n"
+                       "Content-type: %s\r\n"
+                       "Date: %s\r\n"
+                       "Connection: close\r\n",
+                       responseNum, responseString,
+                       /* if it's error message, then it's HTML */
+                       (responseNum == HTTP_OK ? found_mime_type : "text/html"),
+                       date_str
+       );
 
 #if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        if (responseNum == HTTP_UNAUTHORIZED) {
                len += sprintf(iobuf + len,
-                               "WWW-Authenticate: Basic realm=\"%s\"\r\n",
-                               g_realm);
+                               "WWW-Authenticate: Basic realm=\"%.999s\"\r\n",
+                               g_realm /* %.999s protects from overflowing iobuf[] */
+               );
        }
 #endif
        if (responseNum == HTTP_MOVED_TEMPORARILY) {
-               len += sprintf(iobuf + len, "Location: %s/%s%s\r\n",
+               /* Responding to "GET /dir" with
+                * "HTTP/1.0 302 Found" "Location: /dir/"
+                * - IOW, asking them to repeat with a slash.
+                * Here, overflow IS possible, can't use sprintf:
+                * mkdir test
+                * python -c 'print("get /test?" + ("x" * 8192))' | busybox httpd -i -h .
+                */
+               len += snprintf(iobuf + len, IOBUF_SIZE-3 - len,
+                               "Location: %s/%s%s\r\n",
                                found_moved_temporarily,
                                (g_query ? "?" : ""),
-                               (g_query ? g_query : ""));
+                               (g_query ? g_query : "")
+               );
+               if (len > IOBUF_SIZE-3)
+                       len = IOBUF_SIZE-3;
        }
 
 #if ENABLE_FEATURE_HTTPD_ERROR_PAGES
        if (error_page && access(error_page, R_OK) == 0) {
-               strcat(iobuf, "\r\n");
-               len += 2;
-
-               if (DEBUG)
+               iobuf[len++] = '\r';
+               iobuf[len++] = '\n';
+               if (DEBUG) {
+                       iobuf[len] = '\0';
                        fprintf(stderr, "headers: '%s'\n", iobuf);
+               }
                full_write(STDOUT_FILENO, iobuf, len);
                if (DEBUG)
                        fprintf(stderr, "writing error page: '%s'\n", error_page);
@@ -987,13 +1128,15 @@ static void send_headers(int responseNum)
 #endif
 
        if (file_size != -1) {    /* file */
-               strftime(tmp_str, sizeof(tmp_str), RFC1123FMT, gmtime(&last_mod));
+               strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime(&last_mod));
 #if ENABLE_FEATURE_HTTPD_RANGES
                if (responseNum == HTTP_PARTIAL_CONTENT) {
-                       len += sprintf(iobuf + len, "Content-Range: bytes %"OFF_FMT"u-%"OFF_FMT"u/%"OFF_FMT"u\r\n",
+                       len += sprintf(iobuf + len,
+                               "Content-Range: bytes %"OFF_FMT"u-%"OFF_FMT"u/%"OFF_FMT"u\r\n",
                                        range_start,
                                        range_end,
-                                       file_size);
+                                       file_size
+                       );
                        file_size = range_end - range_start + 1;
                }
 #endif
@@ -1001,9 +1144,10 @@ static void send_headers(int responseNum)
 #if ENABLE_FEATURE_HTTPD_RANGES
                        "Accept-Ranges: bytes\r\n"
 #endif
-                       "Last-Modified: %s\r\n%s %"OFF_FMT"u\r\n",
-                               tmp_str,
-                               content_gzip ? "Transfer-length:" : "Content-length:",
+                       "Last-Modified: %s\r\n"
+                       "%s %"OFF_FMT"u\r\n",
+                               date_str,
+                               content_gzip ? "Transfer-Length:" : "Content-Length:",
                                file_size
                );
        }
@@ -1016,12 +1160,18 @@ static void send_headers(int responseNum)
        if (infoString) {
                len += sprintf(iobuf + len,
                                "<HTML><HEAD><TITLE>%d %s</TITLE></HEAD>\n"
-                               "<BODY><H1>%d %s</H1>\n%s\n</BODY></HTML>\n",
+                               "<BODY><H1>%d %s</H1>\n"
+                               "%s\n"
+                               "</BODY></HTML>\n",
+                               responseNum, responseString,
                                responseNum, responseString,
-                               responseNum, responseString, infoString);
+                               infoString
+               );
        }
-       if (DEBUG)
+       if (DEBUG) {
+               iobuf[len] = '\0';
                fprintf(stderr, "headers: '%s'\n", iobuf);
+       }
        if (full_write(STDOUT_FILENO, iobuf, len) != len) {
                if (verbose > 1)
                        bb_perror_msg("error");
@@ -1052,7 +1202,7 @@ static int get_line(void)
        alarm(HEADER_READ_TIMEOUT);
        while (1) {
                if (hdr_cnt <= 0) {
-                       hdr_cnt = safe_read(STDIN_FILENO, hdr_buf, sizeof(hdr_buf));
+                       hdr_cnt = safe_read(STDIN_FILENO, hdr_buf, sizeof_hdr_buf);
                        if (hdr_cnt <= 0)
                                break;
                        hdr_ptr = hdr_buf;
@@ -1103,18 +1253,31 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
 
        /* NB: breaking out of this loop jumps to log_and_exit() */
        out_cnt = 0;
+       pfd[FROM_CGI].fd = fromCgi_rd;
+       pfd[FROM_CGI].events = POLLIN;
+       pfd[TO_CGI].fd = toCgi_wr;
        while (1) {
-               memset(pfd, 0, sizeof(pfd));
-
-               pfd[FROM_CGI].fd = fromCgi_rd;
-               pfd[FROM_CGI].events = POLLIN;
-
-               if (toCgi_wr) {
-                       pfd[TO_CGI].fd = toCgi_wr;
-                       if (hdr_cnt > 0) {
-                               pfd[TO_CGI].events = POLLOUT;
-                       } else if (post_len > 0) {
-                               pfd[0].events = POLLIN;
+               /* Note: even pfd[0].events == 0 won't prevent
+                * revents == POLLHUP|POLLERR reports from closed stdin.
+                * Setting fd to -1 works: */
+               pfd[0].fd = -1;
+               pfd[0].events = POLLIN;
+               pfd[0].revents = 0; /* probably not needed, paranoia */
+
+               /* We always poll this fd, thus kernel always sets revents: */
+               /*pfd[FROM_CGI].events = POLLIN; - moved out of loop */
+               /*pfd[FROM_CGI].revents = 0; - not needed */
+
+               /* gcc-4.8.0 still doesnt fill two shorts with one insn :( */
+               /* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47059 */
+               /* hopefully one day it will... */
+               pfd[TO_CGI].events = POLLOUT;
+               pfd[TO_CGI].revents = 0; /* needed! */
+
+               if (toCgi_wr && hdr_cnt <= 0) {
+                       if (post_len > 0) {
+                               /* Expect more POST data from network */
+                               pfd[0].fd = 0;
                        } else {
                                /* post_len <= 0 && hdr_cnt <= 0:
                                 * no more POST data to CGI,
@@ -1126,7 +1289,7 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
                }
 
                /* Now wait on the set of sockets */
-               count = safe_poll(pfd, toCgi_wr ? TO_CGI+1 : FROM_CGI+1, -1);
+               count = safe_poll(pfd, hdr_cnt > 0 ? TO_CGI+1 : FROM_CGI+1, -1);
                if (count <= 0) {
 #if 0
                        if (safe_waitpid(pid, &status, WNOHANG) <= 0) {
@@ -1143,7 +1306,7 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
                }
 
                if (pfd[TO_CGI].revents) {
-                       /* hdr_cnt > 0 here due to the way pfd[TO_CGI].events set */
+                       /* hdr_cnt > 0 here due to the way poll() called */
                        /* Have data from peer and can write to CGI */
                        count = safe_write(toCgi_wr, hdr_ptr, hdr_cnt);
                        /* Doesn't happen, we dont use nonblocking IO here
@@ -1164,9 +1327,9 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
                        /* We expect data, prev data portion is eaten by CGI
                         * and there *is* data to read from the peer
                         * (POSTDATA) */
-                       //count = post_len > (int)sizeof(hdr_buf) ? (int)sizeof(hdr_buf) : post_len;
+                       //count = post_len > (int)sizeof_hdr_buf ? (int)sizeof_hdr_buf : post_len;
                        //count = safe_read(STDIN_FILENO, hdr_buf, count);
-                       count = safe_read(STDIN_FILENO, hdr_buf, sizeof(hdr_buf));
+                       count = safe_read(STDIN_FILENO, hdr_buf, sizeof_hdr_buf);
                        if (count > 0) {
                                hdr_cnt = count;
                                hdr_ptr = hdr_buf;
@@ -1208,12 +1371,12 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
                                out_cnt += count;
                                count = 0;
                                /* "Status" header format is: "Status: 302 Redirected\r\n" */
-                               if (out_cnt >= 8 && memcmp(rbuf, "Status: ", 8) == 0) {
+                               if (out_cnt >= 7 && memcmp(rbuf, "Status:", 7) == 0) {
                                        /* send "HTTP/1.0 " */
                                        if (full_write(STDOUT_FILENO, HTTP_200, 9) != 9)
                                                break;
-                                       rbuf += 8; /* skip "Status: " */
-                                       count = out_cnt - 8;
+                                       rbuf += 7; /* skip "Status:" */
+                                       count = out_cnt - 7;
                                        out_cnt = -1; /* buffering off */
                                } else if (out_cnt >= 4) {
                                        /* Did CGI add "HTTP"? */
@@ -1361,11 +1524,11 @@ static void send_cgi_and_exit(
 #endif
                }
        }
-       setenv1("HTTP_USER_AGENT", user_agent);
-       if (http_accept)
-               setenv1("HTTP_ACCEPT", http_accept);
-       if (http_accept_language)
-               setenv1("HTTP_ACCEPT_LANGUAGE", http_accept_language);
+       setenv1("HTTP_USER_AGENT", G.user_agent);
+       if (G.http_accept)
+               setenv1("HTTP_ACCEPT", G.http_accept);
+       if (G.http_accept_language)
+               setenv1("HTTP_ACCEPT_LANGUAGE", G.http_accept_language);
        if (post_len)
                putenv(xasprintf("CONTENT_LENGTH=%d", post_len));
        if (cookie)
@@ -1378,9 +1541,9 @@ static void send_cgi_and_exit(
                putenv((char*)"AUTH_TYPE=Basic");
        }
 #endif
-       if (referer)
-               setenv1("HTTP_REFERER", referer);
-       setenv1("HTTP_HOST", host); /* set to "" if NULL */
+       if (G.referer)
+               setenv1("HTTP_REFERER", G.referer);
+       setenv1("HTTP_HOST", G.host); /* set to "" if NULL */
        /* setenv1("SERVER_NAME", safe_gethostname()); - don't do this,
         * just run "env SERVER_NAME=xyz httpd ..." instead */
 
@@ -1413,7 +1576,7 @@ static void send_cgi_and_exit(
                if (script != url) { /* paranoia */
                        *script = '\0';
                        if (chdir(url + 1) != 0) {
-                               bb_perror_msg("chdir(%s)", url + 1);
+                               bb_perror_msg("can't change directory to '%s'", url + 1);
                                goto error_execing_cgi;
                        }
                        // not needed: *script = '/';
@@ -1589,18 +1752,18 @@ static NOINLINE void send_file_and_exit(const char *url, int what)
        if (what == SEND_BODY /* err pages and ranges don't mix */
         || content_gzip /* we are sending compressed page: can't do ranges */  ///why?
        ) {
-               range_start = 0;
+               range_start = -1;
        }
        range_len = MAXINT(off_t);
-       if (range_start) {
-               if (!range_end) {
+       if (range_start >= 0) {
+               if (!range_end || range_end > file_size - 1) {
                        range_end = file_size - 1;
                }
                if (range_end < range_start
                 || lseek(fd, range_start, SEEK_SET) != range_start
                ) {
                        lseek(fd, 0, SEEK_SET);
-                       range_start = 0;
+                       range_start = -1;
                } else {
                        range_len = range_end - range_start + 1;
                        send_headers(HTTP_PARTIAL_CONTENT);
@@ -1610,7 +1773,7 @@ static NOINLINE void send_file_and_exit(const char *url, int what)
 #endif
        if (what & SEND_HEADERS)
                send_headers(HTTP_OK);
-#if ENABLE_FEATURE_HTTPD_USE_SENDFILE
+#if ENABLE_FEATURE_USE_SENDFILE
        {
                off_t offset = range_start;
                while (1) {
@@ -1640,7 +1803,7 @@ static NOINLINE void send_file_and_exit(const char *url, int what)
                        break;
        }
        if (count < 0) {
- IF_FEATURE_HTTPD_USE_SENDFILE(fin:)
+ IF_FEATURE_USE_SENDFILE(fin:)
                if (verbose > 1)
                        bb_perror_msg("error");
        }
@@ -1675,7 +1838,7 @@ static int checkPermIP(void)
 
 #if ENABLE_FEATURE_HTTPD_BASIC_AUTH
 
-# if ENABLE_FEATURE_HTTPD_AUTH_MD5 && ENABLE_PAM
+# if ENABLE_PAM
 struct pam_userinfo {
        const char *name;
        const char *pw;
@@ -1707,9 +1870,9 @@ static int pam_talker(int num_msg,
                case PAM_PROMPT_ECHO_OFF:
                        s = userinfo->pw;
                        break;
-               case PAM_ERROR_MSG:
-               case PAM_TEXT_INFO:
-                       s = "";
+               case PAM_ERROR_MSG:
+               case PAM_TEXT_INFO:
+                       s = "";
                        break;
                default:
                        free(response);
@@ -1841,7 +2004,9 @@ static int check_user_passwd(const char *path, char *user_and_passwd)
 
                        if (passwd[0] == '$' && isdigit(passwd[1])) {
                                char *encrypted;
+# if !ENABLE_PAM
  check_encrypted:
+# endif
                                /* encrypt pwd from peer and check match with local one */
                                encrypted = pw_encrypt(
                                        /* pwd (from peer): */  colon_after_user + 1,
@@ -1878,7 +2043,7 @@ static Htaccess_Proxy *find_proxy_entry(const char *url)
 {
        Htaccess_Proxy *p;
        for (p = proxy; p; p = p->next) {
-               if (strncmp(url, p->url_from, strlen(p->url_from)) == 0)
+               if (is_prefixed_with(url, p->url_from))
                        return p;
        }
        return NULL;
@@ -1961,7 +2126,9 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
                send_headers_and_exit(HTTP_BAD_REQUEST);
 
        /* Determine type of request (GET/POST) */
-       urlp = strpbrk(iobuf, " \t");
+       // rfc2616: method and URI is separated by exactly one space
+       //urlp = strpbrk(iobuf, " \t"); - no, tab isn't allowed
+       urlp = strchr(iobuf, ' ');
        if (urlp == NULL)
                send_headers_and_exit(HTTP_BAD_REQUEST);
        *urlp++ = '\0';
@@ -1979,7 +2146,8 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
        if (strcasecmp(iobuf, request_GET) != 0)
                send_headers_and_exit(HTTP_NOT_IMPLEMENTED);
 #endif
-       urlp = skip_whitespace(urlp);
+       // rfc2616: method and URI is separated by exactly one space
+       //urlp = skip_whitespace(urlp); - should not be necessary
        if (urlp[0] != '/')
                send_headers_and_exit(HTTP_BAD_REQUEST);
 
@@ -2096,10 +2264,8 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
 #if ENABLE_FEATURE_HTTPD_PROXY
                        /* We need 2 more bytes for yet another "\r\n" -
                         * see near fdprintf(proxy_fd...) further below */
-                       if (proxy_entry && (header_ptr - header_buf) < IOBUF_SIZE - 2) {
-                               int len = strlen(iobuf);
-                               if (len > IOBUF_SIZE - (header_ptr - header_buf) - 4)
-                                       len = IOBUF_SIZE - (header_ptr - header_buf) - 4;
+                       if (proxy_entry && (header_ptr - header_buf) < IOBUF_SIZE - 4) {
+                               int len = strnlen(iobuf, IOBUF_SIZE - (header_ptr - header_buf) - 4);
                                memcpy(header_ptr, iobuf, len);
                                header_ptr += len;
                                header_ptr[0] = '\r';
@@ -2110,14 +2276,14 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
 
 #if ENABLE_FEATURE_HTTPD_CGI || ENABLE_FEATURE_HTTPD_PROXY
                        /* Try and do our best to parse more lines */
-                       if ((STRNCASECMP(iobuf, "Content-length:") == 0)) {
+                       if ((STRNCASECMP(iobuf, "Content-Length:") == 0)) {
                                /* extra read only for POST */
                                if (prequest != request_GET
 # if ENABLE_FEATURE_HTTPD_CGI
                                 && prequest != request_HEAD
 # endif
                                ) {
-                                       tptr = skip_whitespace(iobuf + sizeof("Content-length:") - 1);
+                                       tptr = skip_whitespace(iobuf + sizeof("Content-Length:") - 1);
                                        if (!tptr[0])
                                                send_headers_and_exit(HTTP_BAD_REQUEST);
                                        /* not using strtoul: it ignores leading minus! */
@@ -2130,19 +2296,26 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
 #endif
 #if ENABLE_FEATURE_HTTPD_CGI
                        else if (STRNCASECMP(iobuf, "Cookie:") == 0) {
-                               cookie = xstrdup(skip_whitespace(iobuf + sizeof("Cookie:")-1));
+                               if (!cookie) /* in case they send millions of these, do not OOM */
+                                       cookie = xstrdup(skip_whitespace(iobuf + sizeof("Cookie:")-1));
                        } else if (STRNCASECMP(iobuf, "Content-Type:") == 0) {
-                               content_type = xstrdup(skip_whitespace(iobuf + sizeof("Content-Type:")-1));
+                               if (!content_type)
+                                       content_type = xstrdup(skip_whitespace(iobuf + sizeof("Content-Type:")-1));
                        } else if (STRNCASECMP(iobuf, "Referer:") == 0) {
-                               referer = xstrdup(skip_whitespace(iobuf + sizeof("Referer:")-1));
+                               if (!G.referer)
+                                       G.referer = xstrdup(skip_whitespace(iobuf + sizeof("Referer:")-1));
                        } else if (STRNCASECMP(iobuf, "User-Agent:") == 0) {
-                               user_agent = xstrdup(skip_whitespace(iobuf + sizeof("User-Agent:")-1));
+                               if (!G.user_agent)
+                                       G.user_agent = xstrdup(skip_whitespace(iobuf + sizeof("User-Agent:")-1));
                        } else if (STRNCASECMP(iobuf, "Host:") == 0) {
-                               host = xstrdup(skip_whitespace(iobuf + sizeof("Host:")-1));
+                               if (!G.host)
+                                       G.host = xstrdup(skip_whitespace(iobuf + sizeof("Host:")-1));
                        } else if (STRNCASECMP(iobuf, "Accept:") == 0) {
-                               http_accept = xstrdup(skip_whitespace(iobuf + sizeof("Accept:")-1));
+                               if (!G.http_accept)
+                                       G.http_accept = xstrdup(skip_whitespace(iobuf + sizeof("Accept:")-1));
                        } else if (STRNCASECMP(iobuf, "Accept-Language:") == 0) {
-                               http_accept_language = xstrdup(skip_whitespace(iobuf + sizeof("Accept-Language:")-1));
+                               if (!G.http_accept_language)
+                                       G.http_accept_language = xstrdup(skip_whitespace(iobuf + sizeof("Accept-Language:")-1));
                        }
 #endif
 #if ENABLE_FEATURE_HTTPD_BASIC_AUTH
@@ -2164,15 +2337,15 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
                        if (STRNCASECMP(iobuf, "Range:") == 0) {
                                /* We know only bytes=NNN-[MMM] */
                                char *s = skip_whitespace(iobuf + sizeof("Range:")-1);
-                               if (strncmp(s, "bytes=", 6) == 0) {
+                               if (is_prefixed_with(s, "bytes=") == 0) {
                                        s += sizeof("bytes=")-1;
                                        range_start = BB_STRTOOFF(s, &s, 10);
                                        if (s[0] != '-' || range_start < 0) {
-                                               range_start = 0;
+                                               range_start = -1;
                                        } else if (s[1]) {
                                                range_end = BB_STRTOOFF(s+1, NULL, 10);
                                                if (errno || range_end < range_start)
-                                                       range_start = 0;
+                                                       range_start = -1;
                                        }
                                }
                        }
@@ -2223,12 +2396,12 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
                int proxy_fd;
                len_and_sockaddr *lsa;
 
-               proxy_fd = socket(AF_INET, SOCK_STREAM, 0);
-               if (proxy_fd < 0)
-                       send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
                lsa = host2sockaddr(proxy_entry->host_port, 80);
                if (lsa == NULL)
                        send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
+               proxy_fd = socket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
+               if (proxy_fd < 0)
+                       send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
                if (connect(proxy_fd, &lsa->u.sa, lsa->len) < 0)
                        send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
                fdprintf(proxy_fd, "%s %s%s%s%s HTTP/%c.%c\r\n",
@@ -2250,7 +2423,7 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
        tptr = urlcopy + 1;      /* skip first '/' */
 
 #if ENABLE_FEATURE_HTTPD_CGI
-       if (strncmp(tptr, "cgi-bin/", 8) == 0) {
+       if (is_prefixed_with(tptr, "cgi-bin/")) {
                if (tptr[8] == '\0') {
                        /* protect listing "cgi-bin/" */
                        send_headers_and_exit(HTTP_FORBIDDEN);
@@ -2333,7 +2506,7 @@ static void mini_httpd(int server_socket)
                        continue;
 
                /* set the KEEPALIVE option to cull dead connections */
-               setsockopt(n, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
+               setsockopt_keepalive(n);
 
                if (fork() == 0) {
                        /* child */
@@ -2376,7 +2549,7 @@ static void mini_httpd_nommu(int server_socket, int argc, char **argv)
                        continue;
 
                /* set the KEEPALIVE option to cull dead connections */
-               setsockopt(n, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
+               setsockopt_keepalive(n);
 
                if (vfork() == 0) {
                        /* child */