configs/config.samples/L001

   1 /*
   2  * uvscan local_scan() function for Exim (requires at least Exim v4.14)
   3  * known to work with VirusScan for Linux v4.16.0 (Scan engine v4.2.40)
   4  * but should be OK with other platforms
   5  *
   6  * this file is free software (license=GNU GPLv2) and comes with no
   7  * guarantees--if it breaks, you get to keep the pieces (maybe not the mail)!
   8  *
   9  * by (ie patches / flames to): mb/local_scan@dcs.qmul.ac.uk, 2003-05-02
  10  * (original version on 2002-05-25)
  11  */
  12
  13 #include <unistd.h>
  14 #include <stdlib.h>
  15 #include <sys/types.h>
  16 #include <sys/wait.h>
  17 #include <fcntl.h>
  18 #include <string.h>
  19 #include "local_scan.h"
  20
  21 /*
  22  * remember to set LOCAL_SCAN_HAS_OPTIONS=yes in Local/Makefile
  23  * otherwise you get stuck with the compile-time defaults
  24  */
  25
  26 static uschar *uvscan_binary = US"/usr/local/uvscan/uvscan";
  27 static uschar *data_directory = US"/usr/local/uvscan";
  28
  29 optionlist local_scan_options[] = { /* alphabetical order */
  30         { "data_directory", opt_stringptr, &data_directory },
  31         { "uvscan_binary", opt_stringptr, &uvscan_binary }
  32 };
  33
  34 int local_scan_options_count = sizeof(local_scan_options)/sizeof(optionlist);
  35
  36 /* log headers in rejectlog or not? */
  37
  38 //#define VIRUS_IN_MAIL LOCAL_SCAN_REJECT
  39 #define VIRUS_IN_MAIL LOCAL_SCAN_REJECT_NOLOGHDR
  40
  41 /*
  42  * buffer is used both for file copying and catching uvscan's output
  43  * BUFSIZE = 1024 should always be fine
  44  */
  45
  46 #define BUFSIZE 1024
  47
  48 /* some number which uvscan doesn't return */
  49 #define MAGIC 123
  50
  51 /*
  52  * some macros to make the main function more obvious
  53  * NB bailing out might leave tempfiles hanging around
  54  * (and open fds, but no need to be worried about that)
  55  */
  56
  57 #define BAIL(btext) { log_write(0, LOG_MAIN, "UVSCAN ERROR: "btext); \
  58         *return_text = "local scanning problem: please try again later"; \
  59         return LOCAL_SCAN_TEMPREJECT; }
  60
  61 #define DEBUG(dtext) if ((debug_selector & D_local_scan) != 0) \
  62                 { debug_printf(dtext); sleep(1); }
  63         /* sleep useful for running exim -d */
  64
  65 #define RESULT(rtext) header_add(32, \
  66         "X-uvscan-result: "rtext" (%s)\n", message_id);
  67
  68 #define FREEZE(ftext) { header_add(32, \
  69         "X-uvscan-warning: frozen for manual attention (%s)\n", message_id); \
  70         RESULT(ftext); *return_text = ftext; return LOCAL_SCAN_ACCEPT_FREEZE; }
  71
  72 /* OK, enough waffle. On with the show! */
  73
  74 int local_scan(int fd, uschar **return_text)
  75 {
  76         char tf[] = "/tmp/local_scan.XXXXXX"; /* should this be tunable? */
  77         int tmpfd, bytesin, bytesout, pid, status, pipe_fd[2];
  78         fd_set fds;
  79         static uschar buffer[BUFSIZE];
  80
  81         DEBUG("entered uvscan local_scan() function");
  82
  83         /*
  84          * I set majordomo to resend using -oMr lsmtp
  85          * (and yes, I know majordomo isn't actually using SMTP..)
  86          * no point in scanning these beasties twice
  87          */
  88
  89         if(!strcmp(received_protocol, "lsmtp"))
  90                 return LOCAL_SCAN_ACCEPT;
  91
  92         /* create a file to copy the data into */
  93
  94         if ((tmpfd = mkstemp(tf)) == -1)
  95                 BAIL("mkstemp failed");
  96
  97         DEBUG("made tmp file");
  98
  99         /* copy said file BUFSIZE at a time */
 100
 101         while ((bytesin = read(fd, buffer, BUFSIZE)) > 0) {
 102                 bytesout = write(tmpfd, buffer, bytesin);
 103                 if (bytesout < 1)
 104                         BAIL("writing to tmp file");
 105         }
 106         if (bytesin < 0)
 107                 BAIL("reading from spool file");
 108
 109         close(tmpfd);
 110
 111         if(pipe(pipe_fd) == -1)
 112                 BAIL("making pipe");
 113
 114         /* fork and scan */
 115
 116         if((pid = fork()) == -1)
 117                 BAIL("couldn't fork");
 118
 119         if(pid == 0) {
 120                 close(1); /* close stdout */
 121                 if(dup2(pipe_fd[1],1) == -1) /* duplicate write as stdout */
 122                         BAIL("dup2 (stdout) failed");
 123                 if(fcntl(1,F_SETFD,0) == -1) /* fd to NOT close on exec() */
 124                         BAIL("fcntl (stdout) failed");
 125
 126                 execl(uvscan_binary, uvscan_binary, "--mime", "--secure",
 127                         "-d", data_directory, tf, NULL);
 128                 DEBUG("execl failed");
 129                 _exit(MAGIC);
 130         }
 131
 132         if(waitpid(pid, &status, 0) < 1)
 133                 BAIL("couldn't wait for child");
 134
 135         DEBUG("about to unlink");
 136
 137         if(unlink(tf) == -1)
 138                 FREEZE("couldn't unlink tmp file");
 139
 140         DEBUG("unlinked :)");
 141
 142         /*
 143          * choose what to do based on the return code of uvscan
 144          * RESULT() or FREEZE() according to personal taste
 145          */
 146
 147         if(WIFEXITED(status) != 0)
 148                 switch(WEXITSTATUS(status)) {
 149                 case 0: RESULT("clean"); break;
 150                 case 2: RESULT("driver integrity check failed"); break;
 151                 case 6: FREEZE("general problem occurred"); break;
 152                 case 8: RESULT("could not find a driver"); break;
 153                 case 12: FREEZE("failed to clean file"); break;
 154                 case 13:
 155                         // RESULT("virus detected"); /* were we to accept */
 156                         DEBUG("about to read from uvscan process");
 157                         FD_ZERO(&fds);
 158                         FD_SET(pipe_fd[0], &fds);
 159                         if(select(pipe_fd[0]+1, &fds, NULL, NULL, NULL)) {
 160                                 /* last NULL above means wait forever! */
 161                                 DEBUG("select returned non-zero");
 162                                 if((bytesin = read(pipe_fd[0], buffer,
 163                                                 BUFSIZE - 1)) > 0) {
 164                                         buffer[bytesin] = (uschar)0;
 165                                         *return_text = buffer + 22;
 166                                         /* 22 was empirically found ;) */
 167                                         return VIRUS_IN_MAIL;
 168                                 } else
 169                                         BAIL("reading from uvscan process");
 170                         }
 171                         break;
 172                 case 15: FREEZE("self-check failed"); break;
 173                 case 19: FREEZE("virus detected and cleaned"); break;
 174                 case MAGIC: RESULT("couldn't run uvscan"); break;
 175                 default:
 176                         RESULT("unknown error code");
 177                         header_add(32, "X-uvscan-status: %d\n",
 178                                 WEXITSTATUS(status));
 179                         break;
 180                 }
 181         else
 182                 BAIL("child exited abnormally");
 183
 184         return LOCAL_SCAN_ACCEPT;
 185 }