/* some simple CGI helper routines Copyright (C) Andrew Tridgell 1997-1998 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "includes.h" #include "smb.h" #define MAX_VARIABLES 10000 /* set the expiry on fixed pages */ #define EXPIRY_TIME (60*60*24*7) #ifdef DEBUG_COMMENTS extern void print_title(char *fmt, ...); #endif struct var { char *name; char *value; }; static struct var variables[MAX_VARIABLES]; static int num_variables; static int content_length; static int request_post; static char *query_string; static char *baseurl; static char *pathinfo; static char *C_user; static BOOL inetd_server; static BOOL got_request; static void unescape(char *buf) { char *p=buf; while ((p=strchr_m(p,'+'))) *p = ' '; p = buf; while (p && *p && (p=strchr_m(p,'%'))) { int c1 = p[1]; int c2 = p[2]; if (c1 >= '0' && c1 <= '9') c1 = c1 - '0'; else if (c1 >= 'A' && c1 <= 'F') c1 = 10 + c1 - 'A'; else if (c1 >= 'a' && c1 <= 'f') c1 = 10 + c1 - 'a'; else {p++; continue;} if (c2 >= '0' && c2 <= '9') c2 = c2 - '0'; else if (c2 >= 'A' && c2 <= 'F') c2 = 10 + c2 - 'A'; else if (c2 >= 'a' && c2 <= 'f') c2 = 10 + c2 - 'a'; else {p++; continue;} *p = (c1<<4) | c2; memcpy(p+1, p+3, strlen(p+3)+1); p++; } } static char *grab_line(FILE *f, int *cl) { char *ret = NULL; int i = 0; int len = 0; while ((*cl)) { int c; if (i == len) { char *ret2; if (len == 0) len = 1024; else len *= 2; ret2 = (char *)Realloc(ret, len); if (!ret2) return ret; ret = ret2; } c = fgetc(f); (*cl)--; if (c == EOF) { (*cl) = 0; break; } if (c == '\r') continue; if (strchr_m("\n&", c)) break; ret[i++] = c; } ret[i] = 0; return ret; } /*************************************************************************** load all the variables passed to the CGI program. May have multiple variables with the same name and the same or different values. Takes a file parameter for simulating CGI invocation eg loading saved preferences. ***************************************************************************/ void cgi_load_variables(FILE *f1) { FILE *f = f1; static char *line; char *p, *s, *tok; int len; #ifdef DEBUG_COMMENTS char dummy[100]=""; print_title(dummy); printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__); #endif if (!f1) { f = stdin; if (!content_length) { p = getenv("CONTENT_LENGTH"); len = p?atoi(p):0; } else { len = content_length; } } else { struct stat st; fstat(fileno(f), &st); len = st.st_size; } if (len > 0 && (f1 || request_post || ((s=getenv("REQUEST_METHOD")) && strcasecmp(s,"POST")==0))) { while (len && (line=grab_line(f, &len))) { p = strchr_m(line,'='); if (!p) continue; *p = 0; variables[num_variables].name = strdup(line); variables[num_variables].value = strdup(p+1); free(line); if (!variables[num_variables].name || !variables[num_variables].value) continue; unescape(variables[num_variables].value); unescape(variables[num_variables].name); #ifdef DEBUG_COMMENTS printf("<!== POST var %s has value \"%s\" ==>\n", variables[num_variables].name, variables[num_variables].value); #endif num_variables++; if (num_variables == MAX_VARIABLES) break; } } if (f1) { #ifdef DEBUG_COMMENTS printf("<!== End dump in cgi_load_variables() ==>\n"); #endif return; } fclose(stdin); open("/dev/null", O_RDWR); if ((s=query_string) || (s=getenv("QUERY_STRING"))) { for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) { p = strchr_m(tok,'='); if (!p) continue; *p = 0; variables[num_variables].name = strdup(tok); variables[num_variables].value = strdup(p+1); if (!variables[num_variables].name || !variables[num_variables].value) continue; unescape(variables[num_variables].value); unescape(variables[num_variables].name); #ifdef DEBUG_COMMENTS printf("<!== Commandline var %s has value \"%s\" ==>\n", variables[num_variables].name, variables[num_variables].value); #endif num_variables++; if (num_variables == MAX_VARIABLES) break; } } #ifdef DEBUG_COMMENTS printf("<!== End dump in cgi_load_variables() ==>\n"); #endif } /*************************************************************************** find a variable passed via CGI Doesn't quite do what you think in the case of POST text variables, because if they exist they might have a value of "" or even " ", depending on the browser. Also doesn't allow for variables[] containing multiple variables with the same name and the same or different values. ***************************************************************************/ char *cgi_variable(char *name) { int i; for (i=0;i<num_variables;i++) if (strcmp(variables[i].name, name) == 0) return variables[i].value; return NULL; } /*************************************************************************** tell a browser about a fatal error in the http processing ***************************************************************************/ static void cgi_setup_error(char *err, char *header, char *info) { if (!got_request) { /* damn browsers don't like getting cut off before they give a request */ char line[1024]; while (fgets(line, sizeof(line)-1, stdin)) { if (strncasecmp(line,"GET ", 4)==0 || strncasecmp(line,"POST ", 5)==0 || strncasecmp(line,"PUT ", 4)==0) { break; } } } printf("HTTP/1.0 %s\r\n%sConnection: close\r\nContent-Type: text/html\r\n\r\n<HTML><HEAD><TITLE>%s</TITLE></HEAD><BODY><H1>%s</H1>%s<p></BODY></HTML>\r\n\r\n", err, header, err, err, info); fclose(stdin); fclose(stdout); exit(0); } /*************************************************************************** tell a browser about a fatal authentication error ***************************************************************************/ static void cgi_auth_error(void) { if (inetd_server) { cgi_setup_error("401 Authorization Required", "WWW-Authenticate: Basic realm=\"SWAT\"\r\n", "You must be authenticated to use this service"); } else { printf("Content-Type: text/html\r\n"); printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n"); printf("<BODY><H1>Installation Error</H1>\n"); printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n"); printf("</BODY></HTML>\r\n"); } exit(0); } /*************************************************************************** authenticate when we are running as a CGI ***************************************************************************/ static void cgi_web_auth(void) { char *user = getenv("REMOTE_USER"); struct passwd *pwd; char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n"; char *tail = "</BODY></HTML>\r\n"; if (!user) { printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n", head, tail); exit(0); } pwd = getpwnam(user); if (!pwd) { printf("%sCannot find user %s<br>%s\n", head, user, tail); exit(0); } setuid(0); setuid(pwd->pw_uid); if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) { printf("%sFailed to become user %s - uid=%d/%d<br>%s\n", head, user, (int)geteuid(), (int)getuid(), tail); exit(0); } } /*************************************************************************** decode a base64 string in-place - simple and slow algorithm ***************************************************************************/ static void base64_decode(char *s) { char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; int bit_offset, byte_offset, idx, i, n; unsigned char *d = (unsigned char *)s; char *p; n=i=0; while (*s && (p=strchr_m(b64,*s))) { idx = (int)(p - b64); byte_offset = (i*6)/8; bit_offset = (i*6)%8; d[byte_offset] &= ~((1<<(8-bit_offset))-1); if (bit_offset < 3) { d[byte_offset] |= (idx << (2-bit_offset)); n = byte_offset+1; } else { d[byte_offset] |= (idx >> (bit_offset-2)); d[byte_offset+1] = 0; d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF; n = byte_offset+2; } s++; i++; } /* null terminate */ d[n] = 0; } /*************************************************************************** handle a http authentication line ***************************************************************************/ static BOOL cgi_handle_authorization(char *line) { char *p, *user, *user_pass; struct passwd *pass = NULL; BOOL got_name = False; BOOL tested_pass = False; fstring default_user_lookup; fstring default_user_pass; /* Dummy user lookup to take the same time as a valid user. */ fstrcpy(default_user_lookup, "zzzz bibble"); fstrcpy(default_user_pass, "123456789"); if (strncasecmp(line,"Basic ", 6)) { goto err; } line += 6; while (line[0] == ' ') line++; base64_decode(line); if (!(p=strchr_m(line,':'))) { /* * Always give the same error so a cracker * cannot tell why we fail. */ goto err; } *p = 0; user = line; user_pass = p+1; /* * Try and get the user from the UNIX password file. */ if(!(pass = Get_Pwnam(user,False))) { /* * Always give the same error so a cracker * cannot tell why we fail. */ got_name = True; goto err; } /* * Validate the password they have given. */ tested_pass = True; if(pass_check(user, user_pass, strlen(user_pass), NULL) == True) { /* * Password was ok. */ if(pass->pw_uid != 0) { /* * We have not authenticated as root, * become the user *permanently*. */ become_user_permanently(pass->pw_uid, pass->pw_gid); } /* Save the users name */ C_user = strdup(user); return True; } err: /* Always take the same time. */ if (!got_name) Get_Pwnam(default_user_lookup,False); if (!tested_pass) pass_check(default_user_lookup, default_user_pass, strlen(default_user_pass), NULL); cgi_setup_error("401 Bad Authorization", "", "username or password incorrect"); return False; } /*************************************************************************** is this root? ***************************************************************************/ BOOL am_root(void) { if (geteuid() == 0) { return( True); } else { return( False); } } /*************************************************************************** return a ptr to the users name ***************************************************************************/ char *cgi_user_name(void) { return(C_user); } /*************************************************************************** handle a file download ***************************************************************************/ static void cgi_download(char *file) { SMB_STRUCT_STAT st; char buf[1024]; int fd, l, i; char *p; /* sanitise the filename */ for (i=0;file[i];i++) { if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) { cgi_setup_error("404 File Not Found","", "Illegal character in filename"); } } if (!file_exist(file, &st)) { cgi_setup_error("404 File Not Found","", "The requested file was not found"); } fd = sys_open(file,O_RDONLY,0); if (fd == -1) { cgi_setup_error("404 File Not Found","", "The requested file was not found"); } printf("HTTP/1.0 200 OK\r\n"); if ((p=strrchr_m(file,'.'))) { if (strcmp(p,".gif")==0) { printf("Content-Type: image/gif\r\n"); } else if (strcmp(p,".jpg")==0) { printf("Content-Type: image/jpeg\r\n"); } else if (strcmp(p,".txt")==0) { printf("Content-Type: text/plain\r\n"); } else { printf("Content-Type: text/html\r\n"); } } printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME)); printf("Content-Length: %d\r\n\r\n", (int)st.st_size); while ((l=read(fd,buf,sizeof(buf)))>0) { fwrite(buf, 1, l, stdout); } close(fd); exit(0); } /*************************************************************************** setup the cgi framework, handling the possability that this program is either run as a true cgi program by a web browser or is itself a mini web server ***************************************************************************/ void cgi_setup(char *rootdir, int auth_required) { BOOL authenticated = False; char line[1024]; char *url=NULL; char *p; if (chdir(rootdir)) { cgi_setup_error("400 Server Error", "", "chdir failed - the server is not configured correctly"); } /* maybe we are running under a web server */ if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) { if (auth_required) { cgi_web_auth(); } return; } inetd_server = True; if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) { cgi_setup_error("400 Server Error", "", "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf "); } /* we are a mini-web server. We need to read the request from stdin and handle authentication etc */ while (fgets(line, sizeof(line)-1, stdin)) { if (line[0] == '\r' || line[0] == '\n') break; if (strncasecmp(line,"GET ", 4)==0) { got_request = True; url = strdup(&line[4]); } else if (strncasecmp(line,"POST ", 5)==0) { got_request = True; request_post = 1; url = strdup(&line[5]); } else if (strncasecmp(line,"PUT ", 4)==0) { got_request = True; cgi_setup_error("400 Bad Request", "", "This server does not accept PUT requests"); } else if (strncasecmp(line,"Authorization: ", 15)==0) { authenticated = cgi_handle_authorization(&line[15]); } else if (strncasecmp(line,"Content-Length: ", 16)==0) { content_length = atoi(&line[16]); } /* ignore all other requests! */ } if (auth_required && !authenticated) { cgi_auth_error(); } if (!url) { cgi_setup_error("400 Bad Request", "", "You must specify a GET or POST request"); } /* trim the URL */ if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) { *p = 0; } while (*url && strchr_m("\r\n",url[strlen(url)-1])) { url[strlen(url)-1] = 0; } /* anything following a ? in the URL is part of the query string */ if ((p=strchr_m(url,'?'))) { query_string = p+1; *p = 0; } string_sub(url, "/swat/", "", 0); if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) { cgi_download(url); } printf("HTTP/1.0 200 OK\r\nConnection: close\r\n"); printf("Date: %s\r\n", http_timestring(time(NULL))); baseurl = ""; pathinfo = url+1; } /*************************************************************************** return the current pages URL ***************************************************************************/ char *cgi_baseurl(void) { if (inetd_server) { return baseurl; } return getenv("SCRIPT_NAME"); } /*************************************************************************** return the current pages path info ***************************************************************************/ char *cgi_pathinfo(void) { char *r; if (inetd_server) { return pathinfo; } r = getenv("PATH_INFO"); if (!r) return ""; if (*r == '/') r++; return r; } /*************************************************************************** return the hostname of the client ***************************************************************************/ char *cgi_remote_host(void) { if (inetd_server) { return get_socket_name(1); } return getenv("REMOTE_HOST"); } /*************************************************************************** return the hostname of the client ***************************************************************************/ char *cgi_remote_addr(void) { if (inetd_server) { return get_socket_addr(1); } return getenv("REMOTE_ADDR"); } /*************************************************************************** return True if the request was a POST ***************************************************************************/ BOOL cgi_waspost(void) { if (inetd_server) { return request_post; } return strequal(getenv("REQUEST_METHOD"), "POST"); }