[Privoxy-devel] PATCH for pcre2 support

[Fabian Keil]

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
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <https://lists.privoxy.org/pipermail/privoxy-devel/attachments/20230618/3632449a/attachment.bin>