From: Kevin McCarthy <kevin@8t8.us>
Date: Sun, 12 Aug 2018 00:59:54 +0000 (-0700)
Subject: Always check UID vs MSN when handling FETCH.
X-Git-Tag: mutt-1-11-rel~96
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a056404c135c45fa6d3708ede46ddf5729116b7f;p=mutt

Always check UID vs MSN when handling FETCH.

Ensure the UID vs MSN check is always done before flags are processed,
not just if the UID happened to appear before the FLAGS.

Improve the debug messages to make it clearer why a fetch response is
being skipped.
---

diff --git a/imap/command.c b/imap/command.c
index feecf942..8e0ed562 100644
--- a/imap/command.c
+++ b/imap/command.c
@@ -765,21 +765,32 @@ static void cmd_parse_fetch (IMAP_DATA* idata, char* s)
 {
   unsigned int msn, uid;
   HEADER *h;
+  char *flags = NULL;
+  int uid_checked = 0;
   int server_changes = 0;
 
   dprint (3, (debugfile, "Handling FETCH\n"));
 
-  if (mutt_atoui (s, &msn) < 0 ||
-      msn < 1 || msn > idata->max_msn)
+  if (mutt_atoui (s, &msn) < 0)
   {
-    dprint (3, (debugfile, "FETCH response ignored for this message\n"));
+    dprint (3, (debugfile, "cmd_parse_fetch: Skipping FETCH response - illegal MSN\n"));
+    return;
+  }
+
+  if (msn < 1 || msn > idata->max_msn)
+  {
+    dprint (3, (debugfile,
+                "cmd_parse_fetch: Skipping FETCH response - MSN %u out of range\n",
+                msn));
     return;
   }
 
   h = idata->msn_index[msn - 1];
   if (!h || !h->active)
   {
-    dprint (3, (debugfile, "FETCH response ignored for this message\n"));
+    dprint (3, (debugfile,
+                "cmd_parse_fetch: Skipping FETCH response - MSN %u not in msn_index\n",
+                msn));
     return;
   }
 
@@ -801,16 +812,29 @@ static void cmd_parse_fetch (IMAP_DATA* idata, char* s)
 
     if (ascii_strncasecmp ("FLAGS", s, 5) == 0)
     {
-      imap_set_flags (idata, h, s, &server_changes);
-      if (server_changes)
+      flags = s;
+      if (uid_checked)
+        break;
+
+      s += 5;
+      SKIPWS(s);
+      if (*s != '(')
       {
-        /* If server flags could conflict with mutt's flags, reopen the mailbox. */
-        if (h->changed)
-          idata->reopen |= IMAP_EXPUNGE_PENDING;
-        else
-          idata->check_status = IMAP_FLAGS_PENDING;
+        dprint (1, (debugfile, "cmd_parse_fetch: bogus FLAGS response: %s\n",
+                    s));
+        return;
+      }
+      s++;
+      while (*s && *s != ')')
+        s++;
+      if (*s == ')')
+        s++;
+      else
+      {
+        dprint (1, (debugfile,
+                    "cmd_parse_fetch: Unterminated FLAGS response: %s\n", s));
+        return;
       }
-      return;
     }
     else if (ascii_strncasecmp ("UID", s, 3) == 0)
     {
@@ -818,14 +842,17 @@ static void cmd_parse_fetch (IMAP_DATA* idata, char* s)
       SKIPWS (s);
       if (mutt_atoui (s, &uid) < 0)
       {
-        dprint (2, (debugfile, "Illegal UID.  Skipping update.\n"));
+        dprint (1, (debugfile, "cmd_parse_fetch: Illegal UID.  Skipping update.\n"));
         return;
       }
       if (uid != HEADER_DATA(h)->uid)
       {
-        dprint (2, (debugfile, "FETCH UID vs MSN mismatch.  Skipping update.\n"));
+        dprint (1, (debugfile, "cmd_parse_fetch: UID vs MSN mismatch.  Skipping update.\n"));
         return;
       }
+      uid_checked = 1;
+      if (flags)
+        break;
       s = imap_next_word (s);
     }
     else if (ascii_strncasecmp ("MODSEQ", s, 6) == 0)
@@ -851,11 +878,24 @@ static void cmd_parse_fetch (IMAP_DATA* idata, char* s)
       }
     }
     else if (*s == ')')
-      s++; /* end of request */
+      break; /* end of request */
     else if (*s)
     {
       dprint (2, (debugfile, "Only handle FLAGS updates\n"));
-      return;
+      break;
+    }
+  }
+
+  if (flags)
+  {
+    imap_set_flags (idata, h, flags, &server_changes);
+    if (server_changes)
+    {
+      /* If server flags could conflict with mutt's flags, reopen the mailbox. */
+      if (h->changed)
+        idata->reopen |= IMAP_EXPUNGE_PENDING;
+      else
+        idata->check_status = IMAP_FLAGS_PENDING;
     }
   }
 }