[Privoxy-devel] PATCH for pcre2 support

[Gagan Sidhu]

have you tried with optimisations disabled just to rule that out?

the error below isn’t telling us much, in my opinion.

it tells it fails in rewrite_url but not where exactly in that function (if i am reading it correctly?)

could you also add this case to the regression tests or show me how i can feed this to privoxy in no-daemon mode to assist ?

Thanks,
Gagan

> On Jun 18, 2023, at 7:54 AM, Fabian Keil <fk at fabiankeil.de> wrote:
> 
> Gagan Sidhu <broly at mac.com> wrote on 2023-06-18 at 07:05:21:
> 
>> sorry for the second response, but i think i found the other issue.
>> 
>> in rewrite_url, it’s calling pcrs_execute_single_command,
>> which calls pcrs_execute exactly as template_fill did (with
>> the same variable for the buffer size and result size).
>> 
>> i have updated the patch to use the same solution you’ve provided earlier in this exchange.
> 
> Thanks for the update.
> 
> In pcrs_execute_single_command() pcrs_execute() isn't called
> in a loop, though, so the update of buffer_size doesn't seem
> needed as the variable isn't read later on.
> 
>> 32d4ba607ab45ee3970c3e5912943bef6192067c517fda26ae4bf18dc0a94119
>> 
>> this should fix the problem you’ve shown below, in case the
>> conditional for pcre2_jit_compile was not the problem.
> 
> I've tested with the latest patch
> (f690d18e858c844de3caf2db2a8acbd70ecabc34d7f288f5d986eae01d1e7de6)
> and it still results in the crash in rewrite_url():
> 
> (gdb) where
> #0  kill () at kill.S:4
> #1  0x00000008008926e0 in __fail (msg=0x80079c824 "stack overflow detected; terminated") at /usr/src/lib/libc/secure/stack_protector.c:130
> #2  0x0000000800892650 in __stack_chk_fail () at /usr/src/lib/libc/secure/stack_protector.c:137
> #3  0x000000000024abed in rewrite_url (old_url=0x801e7b280 "https://slashdot.org/story/23/06/18/0332230/what-happens-when-you-ask-alexa-if-amazon-is-a-monopoly?utm_source=rss1.0mainlinkanon&utm_medium=feed", 
>    pcrs_command=0x801a00180 "s@\\?(utm_source=rss1.0)?(mainlinkanon)?&utm_medium=feed@@") at filters.c:1038
> #4  0x000000000024acf7 in redirect_url (csp=0x800ef1008) at filters.c:1257
> #5  0x00000000002583b5 in crunch_response_triggered (csp=0x800ef1008, crunchers=0x218920 <crunchers_all>) at jcc.c:953
> #6  0x00000000002569d6 in chat (csp=0x800ef1008) at jcc.c:4482
> #7  0x0000000000255736 in serve (csp=0x800ef1008) at jcc.c:5056
> #8  0x000000080073ca7a in thread_start (curthread=0x800e12700) at /usr/src/lib/libthr/thread/thr_create.c:292
> #9  0x0000000000000000 in ?? ()
> Backtrace stopped: Cannot access memory at address 0x7fffdfffe000
> 
> Fabian
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