Bug in quota_get_status

[Markus Gebert]

On 26.06.2014, at 10:28, Franz Knipp <franz at qnipp.com> wrote:

>  the configuration option
> 
> lmtp_rcpt_check_quota = yes

I noticed that too, and my quick&dirty fix was to make quota_get_status() call quota_test_alloc() with size = 1, which fixes the problem as well. See patch below [1].


> didn't work, so I traced down the problem:
> 
> quota_get_status (quota_storage.c:89) calls quota_test_alloc
> (quota.c:1352) with size = 0 bytes, which leads always to a FALSE result
> in quota_is_over (quota.c:1305).
> 
> I've fixed the function quota_is_over by considering ctx->bytes_over and
> ctx->count_over. See the included patch.

I keep wondering why quota_is_over() does not just check ctx->*_over in the first place instead of doing math with ctx->*_used and ctx->*_ceil. It would seem so much easier. So either ctx->*over was added after quota_is_over() had been written, or this is an oversight, or there’s a specific reason the author did not use/trust ctx->*_over and preferred doing it in a more complicated way. Grepping trough the file, I see much more places the the ctx->*_used and ctx->*_ceil get updated compared to ctx->*_over, so that might indicate that the latter is only updated in specific cases, and cannot be trusted under all circumstances. Then again, I just took a short look at the quota code, so this hunch might me completely wrong.



Markus



[1]
--- src/plugins/quota/quota-storage.c.orig	2014-05-24 17:06:44.822308741 +0200
+++ src/plugins/quota/quota-storage.c	2014-05-24 17:06:55.340307810 +0200
@@ -86,7 +86,7 @@
 
 	if ((items & STATUS_CHECK_OVER_QUOTA) != 0) {
 		qt = quota_transaction_begin(box);
-		if ((ret = quota_test_alloc(qt, 0, &too_large)) == 0) {
+		if ((ret = quota_test_alloc(qt, 1, &too_large)) == 0) {
 			mail_storage_set_error(box->storage, MAIL_ERROR_NOSPACE,
 					       qt->quota->set->quota_exceeded_msg);
 			ret = -1;