Re: dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= S->used' failed

Hi All,

I'm encountering the same issue and the problem seems to be the function 
"p_string_erase" in "dm_string.c"

The assertion around line 160 fails because the 'len' is bigger than the 
S->used (pos is always 0 as far as i've seen).

I'm assuming this is because 'len' represents the line-count for the 
operation, and S->used holds the size of the array of parsed lines. My 
guess is malformed messages cause the system to believe there are N 
lines where there are in fact only M lines available in the array. The 
p_string_erase function gets called with a bad / too big argument 'len', 
tests the assertion and just exits (which is a huge over-reaction for 
production code)

Because I did not have time or the means to analyse the true nature of 
the code I've just implemented a dirty workaround and hoped for the 
best, which at this point seems to be working just fine. Untill someone 
comes up with a true fix I suggest replacing the function with this:

T p_string_erase(T S, size_t pos, int len)

	{

	assert(S);

	assert(pos <= S->used);

	// attempted workaround by marius size_t tw=len; if (tw > S->used){ 
fprintf(stderr, "ASSERT WILL NOW CRASH BUT LETS ATTEMPT A WORKAROUND 
[%zu] [%zu] [%u] [%s]\n",S->used,pos,len,S->str); len = S->used; } // 
END OF WORKAROUND

	if (len < 0)

	len = S->used - pos;

	else {

	assert (pos + len <= S->used);

	

	if (pos + len < S->used)

	memmove (S->str + pos, S->str + pos + len, S->used - (pos + len));

	}

	

	S->used -= len;

	

	S->str[S->used] = 0;

	

	return S;

	}



Regards,
Marius Karthaus
BudgetDedicated.com

Op 27-09-15 om 11:50 schreef Reindl Harald:
> that's not funny and leads in multiple crashes and systemd-restart of 
> dbmail-imapd for two days now and it appears to be triggered by 
> specific clients because it was away for many hours and started again 
> in the evening every few minutes
>
> Sep 27 11:09:46 mail systemd: dbmail-imapd.service: main process 
> exited, code=killed, status=6/ABRT
> Sep 27 11:09:46 mail systemd: Unit dbmail-imapd.service entered failed 
> state.
> Sep 27 11:09:46 mail systemd: dbmail-imapd.service failed.
> Sep 27 11:09:47 mail systemd: dbmail-imapd.service holdoff time over, 
> scheduling restart.
> Sep 27 11:09:47 mail systemd: Stopping DBMail IMAP Server...
> Sep 27 11:09:47 mail systemd: Starting DBMail IMAP Server...
> Sep 27 11:09:47 mail systemd: Started DBMail IMAP Server.
> Sep 27 11:10:04 mail systemd: dbmail-imapd.service: main process 
> exited, code=killed, status=6/ABRT
> Sep 27 11:10:04 mail systemd: Unit dbmail-imapd.service entered failed 
> state.
> Sep 27 11:10:04 mail systemd: dbmail-imapd.service failed.
> Sep 27 11:10:05 mail systemd: dbmail-imapd.service holdoff time over, 
> scheduling restart.
> Sep 27 11:10:05 mail systemd: Stopping DBMail IMAP Server...
> Sep 27 11:10:05 mail systemd: Starting DBMail IMAP Server...
> Sep 27 11:10:05 mail systemd: Started DBMail IMAP Server.
> Sep 27 11:12:25 mail systemd: dbmail-imapd.service: main process 
> exited, code=killed, status=6/ABRT
> Sep 27 11:12:25 mail systemd: Unit dbmail-imapd.service entered failed 
> state.
> Sep 27 11:12:25 mail systemd: dbmail-imapd.service failed.
> Sep 27 11:12:26 mail systemd: dbmail-imapd.service holdoff time over, 
> scheduling restart.
> Sep 27 11:12:26 mail systemd: Stopping DBMail IMAP Server...
> Sep 27 11:12:26 mail systemd: Starting DBMail IMAP Server...
> Sep 27 11:12:26 mail systemd: Started DBMail IMAP Server.
>
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
> dbmail-imapd: dm_string.c:161: p_string_erase: Assertion `pos + len <= 
> S->used' failed.
>
>
>
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