Patch: safeguard against too large value for uid being sent to solr for single mailbox searches

[John Fawcett]

Hi

I'm reposting a patch for solr integration which I have been applying 
locally. It applies against 2.3.17.1.

Dovecot already has a mechanism when doing solr fts searches on multiple 
mailboxes that prevents a too large value for maximum rows being sent to 
solr.

#define SOLR_MAX_MULTI_ROWS 100000

(defined and used in plugins/fts-solr/fts-backend-solr.c)

However on single mailbox searches Dovecot uses the last uid of the 
mailbox, which can be too large for solr. My suggested patch is to also 
limit maximum rows to return on single mailbox searches.

Here is the patch:

diff -ur dovecot-2.3.17.1-orig/src/plugins/fts-solr/fts-backend-solr.c 
dovecot-2.3.17.1-new/src/plugins/fts-solr/fts-backend-solr.c
--- dovecot-2.3.17.1-orig/src/plugins/fts-solr/fts-backend-solr.c 
2021-12-03 12:48:47.000000000 +0100
+++ dovecot-2.3.17.1-new/src/plugins/fts-solr/fts-backend-solr.c 
2022-01-09 01:33:23.401341959 +0100
@@ -837,7 +837,7 @@

         str = t_str_new(256);
         str_printfa(str, 
"wt=xml&fl=uid,score&rows=%u&sort=uid+asc&q=%%7b!lucene+q.op%%3dAND%%7d",
-                   status.uidnext);
+                   I_MIN(status.uidnext,SOLR_MAX_MULTI_ROWS));
         prefix_len = str_len(str);

         if (solr_add_definite_query_args(str, args, and_args)) {

John