Trash Plugin bugs

[Alexei Gradinari]

dovecot v2.2.16

I've found a few bugs in Trash plugin.

1. If Quota set only messages limit (without storage limit) then
Trash plugin does not expunge any message because Quota plugin sets too_large_r=TRUE.
It's because quota_default_test_alloc function does not check if bytes_limit is set.

                /* if size is bigger than any limit, then
                   it is bigger than the lowest limit */
-               if (size > bytes_limit) {
+               if (bytes_limit > 0 && size > bytes_limit) {
                        *too_large_r = TRUE;
                        break;
                }


2. Trash plugin does not use bytes_ceil/count_ceil to calculate size_needed/count_needed to expunge.
Trash plugin may expunge more messages that nedeed.

+               if (ctx->bytes_ceil!=(uint64_t)-1 && ctx->bytes_ceil < size + ctx->bytes_over) {
+                       size_needed = size + ctx->bytes_over - ctx->bytes_ceil;
+               }
+               if (ctx->count_ceil!=(uint64_t)-1 && ctx->count_ceil < 1 + ctx->count_over) {
+                       count_needed = 1 + ctx->count_over - ctx->count_ceil;
+               }
+
                /* not enough space. try deleting some from mailbox. */
-               ret = trash_try_clean_mails(ctx, size + ctx->bytes_over,
-                                           1 + ctx->count_over);
+               ret = trash_try_clean_mails(ctx, size_needed, count_needed);

3. Trash plugin does not check 'unlimited' values in bytes_ceil/count_ceil and may overflow them
when add expunged size/messages

-       ctx->bytes_ceil += size_expunged;
-       ctx->count_ceil += expunged_count;
+       if (ctx->bytes_ceil!=(uint64_t)-1) {
+               ctx->bytes_ceil += size_expunged;
+       }
+       if (ctx->count_ceil!=(uint64_t)-1) {
+               ctx->count_ceil += expunged_count;
+       }


See attached patch.
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