`ssh-log-pw-blank': known password fields are now omitted from SSH packet logs

[u/mdw/putty] / logging.c

diff --git a/logging.c b/logging.c
index 5302998..808e429 100644 (file)
--- a/logging.c
+++ b/logging.c
@@ -70,12 +70,14 @@ void log_eventlog(void *handle, const char *event)
 
 /*
  * Log an SSH packet.
+ * If n_blanks != 0, blank or omit some parts.
+ * Set of blanking areas must be in increasing order.
  */
 void log_packet(void *handle, int direction, int type,
-               char *texttype, void *data, int len)
+               char *texttype, void *data, int len,
+               int n_blanks, const struct logblank_t *blanks)
 {
     struct LogContext *ctx = (struct LogContext *)handle;
-    int i, j;
     char dumpdata[80], smalldata[5];
 
     if (ctx->cfg.logtype != LGTYP_PACKETS)
@@ -83,21 +85,81 @@ void log_packet(void *handle, int direction, int type,
     if (!ctx->lgfp)
        logfopen(ctx);
     if (ctx->lgfp) {
+       int p = 0, b = 0, omitted = 0;
+       int output_pos = 0; /* NZ if pending output in dumpdata */
+
+       /* Packet header. */
        fprintf(ctx->lgfp, "%s packet type %d / 0x%02x (%s)\r\n",
                direction == PKT_INCOMING ? "Incoming" : "Outgoing",
                type, type, texttype);
-       for (i = 0; i < len; i += 16) {
-           sprintf(dumpdata, "  %08x%*s\r\n", i, 1+3*16+2+16, "");
-           for (j = 0; j < 16 && i+j < len; j++) {
-               int c = ((unsigned char *)data)[i+j];
-               sprintf(smalldata, "%02x", c);
-               dumpdata[10+2+3*j] = smalldata[0];
-               dumpdata[10+2+3*j+1] = smalldata[1];
-               dumpdata[10+1+3*16+2+j] = (isprint(c) ? c : '.');
+
+       /*
+        * Output a hex/ASCII dump of the packet body, blanking/omitting
+        * parts as specified.
+        */
+       while (p < len) {
+           int blktype;
+
+           /* Move to a current entry in the blanking array. */
+           while ((b < n_blanks) &&
+                  (p >= blanks[b].offset + blanks[b].len))
+               b++;
+           /* Work out what type of blanking to apply to
+            * this byte. */
+           blktype = PKTLOG_EMIT; /* default */
+           if ((b < n_blanks) &&
+               (p >= blanks[b].offset) &&
+               (p < blanks[b].offset + blanks[b].len))
+               blktype = blanks[b].type;
+
+           /* If we're about to stop omitting, it's time to say how
+            * much we omitted. */
+           if ((blktype != PKTLOG_OMIT) && omitted) {
+               fprintf(ctx->lgfp, "  (%d byte%s omitted)\r\n",
+                       omitted, (omitted==1?"":"s"));
+               omitted = 0;
+           }
+
+           /* (Re-)initialise dumpdata as necessary
+            * (start of row, or if we've just stopped omitting) */
+           if (!output_pos && !omitted)
+               sprintf(dumpdata, "  %08x%*s\r\n", p-(p%16), 1+3*16+2+16, "");
+
+           /* Deal with the current byte. */
+           if (blktype == PKTLOG_OMIT) {
+               omitted++;
+           } else {
+               int c;
+               if (blktype == PKTLOG_BLANK) {
+                   c = 'X';
+                   sprintf(smalldata, "XX");
+               } else {  /* PKTLOG_EMIT */
+                   c = ((unsigned char *)data)[p];
+                   sprintf(smalldata, "%02x", c);
+               }
+               dumpdata[10+2+3*(p%16)] = smalldata[0];
+               dumpdata[10+2+3*(p%16)+1] = smalldata[1];
+               dumpdata[10+1+3*16+2+(p%16)] = (isprint(c) ? c : '.');
+               output_pos = (p%16) + 1;
+           }
+
+           p++;
+
+           /* Flush row if necessary */
+           if (((p % 16) == 0) || (p == len) || omitted) {
+               if (output_pos) {
+                   strcpy(dumpdata + 10+1+3*16+2+output_pos, "\r\n");
+                   fputs(dumpdata, ctx->lgfp);
+                   output_pos = 0;
+               }
            }
-           strcpy(dumpdata + 10+1+3*16+2+j, "\r\n");
-           fputs(dumpdata, ctx->lgfp);
+
        }
+
+       /* Tidy up */
+       if (omitted)
+           fprintf(ctx->lgfp, "  (%d byte%s omitted)\r\n",
+                   omitted, (omitted==1?"":"s"));
        fflush(ctx->lgfp);
     }
 }