httpd: get rid of sscanf usage. Rename some variables.

1 files changed, 110 insertions, 94 deletions

diff --git a/networking/httpd.c b/networking/httpd.c
index c837d67ad..23d442f17 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -110,6 +110,7 @@
 
 static const char default_path_httpd_conf[] ALIGN1 = "/etc";
 static const char httpd_conf[] ALIGN1 = "httpd.conf";
+static const char HTTP_200[] ALIGN1 = "HTTP/1.0 200 OK\r\n";
 
 typedef struct has_next_ptr {
         struct has_next_ptr *next;
@@ -135,6 +136,7 @@ struct globals {
         smallint flg_deny_all;
 
         unsigned rmt_ip;
+// TODO: get rid of rmt_port
         unsigned rmt_port;      /* for set env REMOTE_PORT */
         char *rmt_ip_str;       /* for set env REMOTE_ADDR */
         const char *bind_addr_or_port;
@@ -661,6 +663,22 @@ static char *encodeString(const char *string)
  *
  * Returns a pointer to the decoded string (same as input).
  */
+static unsigned hex_to_bin(unsigned char c)
+{
+        unsigned v = c | 0x20; /* lowercase */
+        v = v - '0';
+        if (v <= 9)
+                return v;
+        v = v + ('0' - 'a');
+        if (v <= 5)
+                return v + 10;
+        return ~0;
+}
+/* For testing:
+void t(char c) { printf("'%c' %u\n", c, hex_to_bin(c)); }
+int main() { t('0'); t('9'); t('A'); t('F'); t('a'); t('f');
+t('0'-1); t('9'+1); t('A'-1); t('F'+1); t('a'-1); t('f'+1); return 0; }
+*/
 static char *decodeString(char *orig, int option_d)
 {
         /* note that decoded string is always shorter than original */
@@ -669,7 +687,7 @@ static char *decodeString(char *orig, int option_d)
         char c;
 
         while ((c = *ptr++) != '\0') {
-                unsigned value1, value2;
+                unsigned v;
 
                 if (option_d && c == '+') {
                         *string++ = ' ';
@@ -679,21 +697,23 @@ static char *decodeString(char *orig, int option_d)
                         *string++ = c;
                         continue;
                 }
-                if (sscanf(ptr, "%1X", &value1) != 1
-                 || sscanf(ptr+1, "%1X", &value2) != 1
-                ) {
+                v = hex_to_bin(ptr[0]);
+                if (v > 15) {
+ bad_hex:
                         if (!option_d)
                                 return NULL;
                         *string++ = '%';
                         continue;
                 }
-                value1 = value1 * 16 + value2;
-                if (!option_d && (value1 == '/' || value1 == '\0')) {
+                v = (v * 16) | hex_to_bin(ptr[1]);
+                if (v > 255)
+                        goto bad_hex;
+                if (!option_d && (v == '/' || v == '\0')) {
                         /* caller takes it as indication of invalid
                          * (dangerous wrt exploits) chars */
                         return orig + 1;
                 }
-                *string++ = value1;
+                *string++ = v;
                 ptr += 2;
         }
         *string = '\0';
@@ -1188,13 +1208,13 @@ static void send_cgi_and_exit(
 
                         /* Are we still buffering CGI output? */
                         if (buf_count >= 0) {
-                                /* According to http://hoohoo.ncsa.uiuc.edu/cgi/out.html,
+                                /* HTTP_200[] has single "\r\n" at the end.
+                                 * According to http://hoohoo.ncsa.uiuc.edu/cgi/out.html,
                                  * CGI scripts MUST send their own header terminated by
                                  * empty line, then data. That's why we have only one
                                  * <cr><lf> pair here. We will output "200 OK" line
                                  * if needed, but CGI still has to provide blank line
                                  * between header and body */
-                                static const char HTTP_200[] ALIGN1 = "HTTP/1.0 200 OK\r\n";
 
                                 /* Must use safe_read, not full_read, because
                                  * CGI may output a few first bytes and then wait
@@ -1489,12 +1509,11 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
 {
         static const char request_GET[] ALIGN1 = "GET";
 
-        char *url;
-        char *purl;
-        int count;
-        int http_major_version;
-        char *test;
         struct stat sb;
+        char *urlcopy;
+        char *urlp;
+        char *tptr;
+        int http_major_version;
         int ip_allowed;
 #if ENABLE_FEATURE_HTTPD_CGI
         const char *prequest;
@@ -1535,58 +1554,57 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
         sigaction(SIGALRM, &sa, NULL);
         alarm(HEADER_READ_TIMEOUT);
 
-        if (!get_line()) {
-                /* EOF or error or empty line */
+        if (!get_line()) /* EOF or error or empty line */
                 send_headers_and_exit(HTTP_BAD_REQUEST);
-        }
 
         /* Determine type of request (GET/POST) */
-        purl = strpbrk(iobuf, " \t");
-        if (purl == NULL) {
+        urlp = strpbrk(iobuf, " \t");
+        if (urlp == NULL)
                 send_headers_and_exit(HTTP_BAD_REQUEST);
-        }
-        *purl = '\0';
+        *urlp++ = '\0';
 #if ENABLE_FEATURE_HTTPD_CGI
         prequest = request_GET;
         if (strcasecmp(iobuf, prequest) != 0) {
                 prequest = "POST";
-                if (strcasecmp(iobuf, prequest) != 0) {
+                if (strcasecmp(iobuf, prequest) != 0)
                         send_headers_and_exit(HTTP_NOT_IMPLEMENTED);
-                }
         }
 #else
-        if (strcasecmp(iobuf, request_GET) != 0) {
+        if (strcasecmp(iobuf, request_GET) != 0)
                 send_headers_and_exit(HTTP_NOT_IMPLEMENTED);
-        }
 #endif
-        *purl = ' ';
+        urlp = skip_whitespace(urlp);
+        if (urlp[0] != '/')
+                send_headers_and_exit(HTTP_BAD_REQUEST);
 
-        /* Copy URL from after "GET "/"POST " to stack-allocated char[] */
+        /* Find end of URL and parse HTTP version, if any */
         http_major_version = -1;
-        count = sscanf(purl, " %[^ ] HTTP/%d.%*d", iobuf, &http_major_version);
-        if (count < 1 || iobuf[0] != '/') {
-                /* Garbled request/URL */
-                send_headers_and_exit(HTTP_BAD_REQUEST);
-        }
-        url = alloca(strlen(iobuf) + sizeof("/index.html"));
-        if (url == NULL) {
-                send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
-        }
-        strcpy(url, iobuf);
+        tptr = strchrnul(urlp, ' ');
+        /* Is it " HTTP/"? */
+        if (tptr[0] && strncmp(tptr + 1, HTTP_200, 5) == 0)
+                http_major_version = (tptr[6] - '0');
+        *tptr = '\0';
+
+        /* Copy URL from after "GET "/"POST " to stack-allocated char[] */
+        urlcopy = alloca((tptr - urlp) + sizeof("/index.html"));
+        /*if (urlcopy == NULL)
+         *      send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);*/
+        strcpy(urlcopy, urlp);
+        /* NB: urlcopy ptr is never changed after this */
 
         /* Extract url args if present */
-        test = strchr(url, '?');
+        tptr = strchr(urlcopy, '?');
         g_query = NULL;
-        if (test) {
-                *test++ = '\0';
-                g_query = test;
+        if (tptr) {
+                *tptr++ = '\0';
+                g_query = tptr;
         }
 
         /* Decode URL escape sequences */
-        test = decodeString(url, 0);
-        if (test == NULL)
+        tptr = decodeString(urlcopy, 0);
+        if (tptr == NULL)
                 send_headers_and_exit(HTTP_BAD_REQUEST);
-        if (test == url + 1) {
+        if (tptr == urlcopy + 1) {
                 /* '/' or NUL is encoded */
                 send_headers_and_exit(HTTP_NOT_FOUND);
         }
@@ -1594,60 +1612,58 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
         /* Canonicalize path */
         /* Algorithm stolen from libbb bb_simplify_path(),
          * but don't strdup and reducing trailing slash and protect out root */
-        purl = test = url;
+        urlp = tptr = urlcopy;
         do {
-                if (*purl == '/') {
+                if (*urlp == '/') {
                         /* skip duplicate (or initial) slash */
-                        if (*test == '/') {
+                        if (*tptr == '/') {
                                 continue;
                         }
-                        if (*test == '.') {
+                        if (*tptr == '.') {
                                 /* skip extra '.' */
-                                if (test[1] == '/' || !test[1]) {
+                                if (tptr[1] == '/' || !tptr[1]) {
                                         continue;
                                 }
                                 /* '..': be careful */
-                                if (test[1] == '.' && (test[2] == '/' || !test[2])) {
-                                        ++test;
-                                        if (purl == url) {
-                                                /* protect root */
+                                if (tptr[1] == '.' && (tptr[2] == '/' || !tptr[2])) {
+                                        ++tptr;
+                                        if (urlp == urlcopy) /* protect root */
                                                 send_headers_and_exit(HTTP_BAD_REQUEST);
-                                        }
-                                        while (*--purl != '/') /* omit previous dir */;
+                                        while (*--urlp != '/') /* omit previous dir */;
                                                 continue;
                                 }
                         }
                 }
-                *++purl = *test;
-        } while (*++test);
-        *++purl = '\0';       /* so keep last character */
-        test = purl;          /* end ptr */
+                *++urlp = *tptr;
+        } while (*++tptr);
+        *++urlp = '\0';       /* so keep last character */
+        tptr = urlp;          /* end ptr */
 
         /* If URL is a directory, add '/' */
-        if (test[-1] != '/') {
-                if (is_directory(url + 1, 1, &sb)) {
-                        found_moved_temporarily = url;
+        if (tptr[-1] != '/') {
+                if (is_directory(urlcopy + 1, 1, &sb)) {
+                        found_moved_temporarily = urlcopy;
                 }
         }
 
         /* Log it */
         if (verbose > 1)
-                bb_error_msg("url:%s", url);
+                bb_error_msg("url:%s", urlcopy);
 
-        test = url;
+        tptr = urlcopy;
         ip_allowed = checkPermIP();
-        while (ip_allowed && (test = strchr(test + 1, '/')) != NULL) {
+        while (ip_allowed && (tptr = strchr(tptr + 1, '/')) != NULL) {
                 /* have path1/path2 */
-                *test = '\0';
-                if (is_directory(url + 1, 1, &sb)) {
+                *tptr = '\0';
+                if (is_directory(urlcopy + 1, 1, &sb)) {
                         /* may be having subdir config */
-                        parse_conf(url + 1, SUBDIR_PARSE);
+                        parse_conf(urlcopy + 1, SUBDIR_PARSE);
                         ip_allowed = checkPermIP();
                 }
-                *test = '/';
+                *tptr = '/';
         }
         if (http_major_version >= 0) {
-                /* Request was with "... HTTP/n.m", and n >= 0 */
+                /* Request was with "... HTTP/nXXX", and n >= 0 */
 
                 /* Read until blank line for HTTP version specified, else parse immediate */
                 while (1) {
@@ -1662,16 +1678,16 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
                         if ((STRNCASECMP(iobuf, "Content-length:") == 0)) {
                                 /* extra read only for POST */
                                 if (prequest != request_GET) {
-                                        test = iobuf + sizeof("Content-length:") - 1;
-                                        if (!test[0])
+                                        tptr = iobuf + sizeof("Content-length:") - 1;
+                                        if (!tptr[0])
                                                 send_headers_and_exit(HTTP_BAD_REQUEST);
                                         errno = 0;
                                         /* not using strtoul: it ignores leading minus! */
-                                        length = strtol(test, &test, 10);
+                                        length = strtol(tptr, &tptr, 10);
                                         /* length is "ulong", but we need to pass it to int later */
                                         /* so we check for negative or too large values in one go: */
                                         /* (long -> ulong conv caused negatives to be seen as > INT_MAX) */
-                                        if (test[0] || errno || length > INT_MAX)
+                                        if (tptr[0] || errno || length > INT_MAX)
                                                 send_headers_and_exit(HTTP_BAD_REQUEST);
                                 }
                         } else if (STRNCASECMP(iobuf, "Cookie:") == 0) {
@@ -1690,13 +1706,13 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
                                  * It shows up as "Authorization: Basic <userid:password>" where
                                  * the userid:password is base64 encoded.
                                  */
-                                test = skip_whitespace(iobuf + sizeof("Authorization:")-1);
-                                if (STRNCASECMP(test, "Basic") != 0)
+                                tptr = skip_whitespace(iobuf + sizeof("Authorization:")-1);
+                                if (STRNCASECMP(tptr, "Basic") != 0)
                                         continue;
-                                test += sizeof("Basic")-1;
+                                tptr += sizeof("Basic")-1;
                                 /* decodeBase64() skips whitespace itself */
-                                decodeBase64(test);
-                                credentials = checkPerm(url, test);
+                                decodeBase64(tptr);
+                                credentials = checkPerm(urlcopy, tptr);
                         }
 #endif          /* FEATURE_HTTPD_BASIC_AUTH */
                 } /* while extra header reading */
@@ -1705,13 +1721,13 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
         /* We read headers, disable peer timeout */
         alarm(0);
 
-        if (strcmp(bb_basename(url), httpd_conf) == 0 || ip_allowed == 0) {
+        if (strcmp(bb_basename(urlcopy), httpd_conf) == 0 || ip_allowed == 0) {
                 /* protect listing [/path]/httpd_conf or IP deny */
                 send_headers_and_exit(HTTP_FORBIDDEN);
         }
 
 #if ENABLE_FEATURE_HTTPD_BASIC_AUTH
-        if (credentials <= 0 && checkPerm(url, ":") == 0) {
+        if (credentials <= 0 && checkPerm(urlcopy, ":") == 0) {
                 send_headers_and_exit(HTTP_UNAUTHORIZED);
         }
 #endif
@@ -1720,24 +1736,24 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
                 send_headers_and_exit(HTTP_MOVED_TEMPORARILY);
         }
 
-        test = url + 1;      /* skip first '/' */
+        tptr = urlcopy + 1;      /* skip first '/' */
 
 #if ENABLE_FEATURE_HTTPD_CGI
-        if (strncmp(test, "cgi-bin/", 8) == 0) {
-                if (test[8] == '\0') {
+        if (strncmp(tptr, "cgi-bin/", 8) == 0) {
+                if (tptr[8] == '\0') {
                         /* protect listing "cgi-bin/" */
                         send_headers_and_exit(HTTP_FORBIDDEN);
                 }
-                send_cgi_and_exit(url, prequest, length, cookie, content_type);
+                send_cgi_and_exit(urlcopy, prequest, length, cookie, content_type);
         }
 #if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
         {
-                char *suffix = strrchr(test, '.');
+                char *suffix = strrchr(tptr, '.');
                 if (suffix) {
                         Htaccess *cur;
                         for (cur = script_i; cur; cur = cur->next) {
                                 if (strcmp(cur->before_colon + 1, suffix) == 0) {
-                                        send_cgi_and_exit(url, prequest, length, cookie, content_type);
+                                        send_cgi_and_exit(urlcopy, prequest, length, cookie, content_type);
                                 }
                         }
                 }
@@ -1748,20 +1764,20 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
         }
 #endif  /* FEATURE_HTTPD_CGI */
 
-        if (purl[-1] == '/')
-                strcpy(purl, "index.html");
-        if (stat(test, &sb) == 0) {
+        if (urlp[-1] == '/')
+                strcpy(urlp, "index.html");
+        if (stat(tptr, &sb) == 0) {
                 /* It's a dir URL and there is index.html */
                 ContentLength = sb.st_size;
                 last_mod = sb.st_mtime;
         }
 #if ENABLE_FEATURE_HTTPD_CGI
-        else if (purl[-1] == '/') {
+        else if (urlp[-1] == '/') {
                 /* It's a dir URL and there is no index.html
                  * Try cgi-bin/index.cgi */
                 if (access("/cgi-bin/index.cgi"+1, X_OK) == 0) {
-                        purl[0] = '\0';
-                        g_query = url;
+                        urlp[0] = '\0';
+                        g_query = urlcopy;
                         send_cgi_and_exit("/cgi-bin/index.cgi", prequest, length, cookie, content_type);
                 }
         }
@@ -1771,7 +1787,7 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
          * }
          */
 
-        send_file_and_exit(test);
+        send_file_and_exit(tptr);
 
 #if 0 /* Is this needed? Why? */
         if (DEBUG)