TJ <dll-kms...@protonmail.com> wrote:
> I'm migrating my system configs from one OpenBSD machine (Pentium 4) to
> another (Core 2 Duo).
>
> I noticed unpredictable crashes of the Privoxy package when run and used
> on the C2D computer. These crashes don't occur on the P4 at all, with
> the same traffic.
I tried to reproduce the crashes with OpenBSD 6.7 amd64
and Privoxy 3.0.29 built from git and Privoxy reliably
crashes when executing a regression test ...
The crash I encountered seems to be triggered by long
host names resolved from a thread.
Here's a reduced test case:
openbsd$ cat resolve.c
#include <netdb.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
pthread_mutex_t mutex;
void resolve(char *host) {
int error;
error = pthread_mutex_lock(&mutex);
if (error) {
printf("Locking failed: %s", strerror(error));
exit(1);
}
printf("Calling gethostbyname with %s\n", host);
gethostbyname(host);
pthread_mutex_unlock(&mutex);
}
int main(int argc, char **argv) {
pthread_t the_thread;
pthread_attr_t attrs;
int i;
if (!argc) {
printf("No argument to resolve given\n");
exit(1);
}
pthread_attr_init(&attrs);
pthread_attr_setdetachstate(&attrs, PTHREAD_CREATE_DETACHED);
pthread_mutex_init(&mutex, NULL);
for (i = 0; i < 3; i++) {
pthread_create(&the_thread, &attrs, (void * (*)(void *))resolve,
argv[1]);
}
sleep(1);
exit(0);
}
openbsd$ clang -pthread -ggdb -Wall -o resolve resolve.c
openbsd$ ./resolve
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA.example.org
Calling gethostbyname with
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA.example.org
Calling gethostbyname with
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA.example.org
Calling gethostbyname with
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA.example.org
openbsd$ ./resolve
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA.example.org
Calling gethostbyname with
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA.example.org
Segmentation fault (core dumped)
openbsd$ egdb resolve resolve.core
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Reading symbols from resolve...done.
[New process 616459]
[New process 145207]
[New process 578084]
[New process 517316]
Core was generated by `resolve'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x0000031a025d201d in unpack_data (p=0x31a6a754b40, data=0x31a6a754b70,
len=12) at /usr/src/lib/libc/asr/asr_utils.c:193
193 /usr/src/lib/libc/asr/asr_utils.c: No such file or directory.
[Current thread is 1 (process 616459)]
(gdb) where
#0 0x0000031a025d201d in unpack_data (p=0x31a6a754b40, data=0x31a6a754b70,
len=12) at /usr/src/lib/libc/asr/asr_utils.c:193
#1 _asr_unpack_header (p=0x31a6a754b40, h=0x31a6a754b70) at
/usr/src/lib/libc/asr/asr_utils.c:257
#2 0x0000031a0265db34 in hostent_from_packet (reqtype=3, family=2,
pkt=<optimized out>, pktlen=<optimized out>) at
/usr/src/lib/libc/asr/gethostnamadr_async.c:463
#3 gethostnamadr_async_run (as=<optimized out>, ar=<optimized out>) at
/usr/src/lib/libc/asr/gethostnamadr_async.c:305
#4 0x0000031a02603308 in _libc_asr_run (as=0x319e01a2e00, ar=0x31a6a754c70) at
/usr/src/lib/libc/asr/asr.c:176
#5 _libc_asr_run_sync (as=0x319e01a2e00, ar=0x31a6a754c70) at
/usr/src/lib/libc/asr/asr.c:223
#6 0x0000031a025f994e in _gethostbyname (name=0x7f7ffffd01ba 'A' <repeats 64
times>, ".example.org", af=2, ret=<optimized out>, buflen=4096,
h_errnop=<optimized out>, buf=<optimized out>)
at /usr/src/lib/libc/asr/gethostnamadr.c:119
#7 _libc_gethostbyname2 (name=0x7f7ffffd01ba 'A' <repeats 64 times>,
".example.org", af=2) at /usr/src/lib/libc/asr/gethostnamadr.c:154
#8 0x00000317d0a323c4 in resolve (host=0x7f7ffffd01ba 'A' <repeats 64 times>,
".example.org") at resolve.c:18
#9 0x0000031ab56970d1 in _rthread_start (v=<optimized out>) at
/usr/src/lib/librthread/rthread.c:96
#10 0x0000031a0264cdb8 in __tfork_thread () at
/usr/src/lib/libc/arch/amd64/sys/tfork_thread.S:77
#11 0x0000000000000000 in ?? ()
Fabian
