Hello again,
I forgot to mention that this system is on a kernel with PaX and
Grsecurity, so GDB doesn't work too well on it.
I would install Jabberd2 on a more normal machine, except this problem
surfaces when installing the old version of libidn Jabberd2 needs.
- Neil
# cat /var/tmp/paludis/net-dns/libidn-0.6.9-r2/temp//autoconf-29295.out
***** autoconf *****
configure.ac:107: error: possibly undefined macro: AC_PROG_JAVAC
If this token and others are legitimate, please use m4_pattern_allow.
See the Autoconf documentation.
configure.ac:108: error: possibly undefined macro: AC_PROG_JAR
On Mon, Mar 17, 2008 at 4:04 PM, Joël Bohnes <[EMAIL PROTECTED]> wrote:
> Hia
>
> free() can segfault if you give it a pointer to unallocated
> memory(either already free()'d or never malloc()'d ).
>
> The buf array gets always initialized in "_sx_sasl_encode".
> There is only one function which uses the buffer after this:
> "gsasl_step", which is a function from the gsasl library - but that
> shouldn't make the pointer invalid.
>
> It's odd that gdb gives you "Failed to read a valid object
> file image from memory.". Many people say that's it's a kernel bug -
> maybe you should think about updating if you use an outdated one.
>
> A "normal" gdb output of a segfault looks like this:
> --
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x0000000000400506 in main () at main.c:7
> 7 (*p)++;
> (gdb) bt
> #0 0x0000000000400506 in main () at main.c:7
> --
>
> In my opinion it isn't easy to find out what the problem using emails -
> the best and easiest thing would be to look at it over ssh with screen
> in multi-user mode
> (http://gentoo-wiki.com/HOWTO_Snoop_terminal_session#Screen). I'd
> really like to have a look at it cause my crystal ball doesn't show
> anything yet.
>
> You can always contact me via jabber ([EMAIL PROTECTED]).
>
> ~Shino
>
>
>
> > Hello, and thank you for responding so quickly,
> >
> > I've done that, and it still doesn't give any useful information.
> >
> > ========== CONSOLE ==========
> > # emerge --info | grep FLAGS
> > CFLAGS="-O2 -march=k8 -pipe -mmmx -msse -msse2 -m3dnow -mfpmath=sse
> > -ggdb" CXXFLAGS="-O2 -march=k8 -pipe -mmmx -msse -msse2 -m3dnow
> > -mfpmath=sse -ggdb" # file /usr/bin/router
> > /usr/bin/router: ELF 64-bit LSB shared object, x86-64, version 1
> > (SYSV), for GNU/Linux 2.6.9, not stripped
> > # gdb /usr/bin/router
> > GNU gdb 6.7.1
> > Copyright (C) 2007 Free Software Foundation, Inc.
> > License GPLv3+: GNU GPL version 3 or later
> > <http://gnu.org/licenses/gpl.html> This is free software: you are
> > free to change and redistribute it. There is NO WARRANTY, to the
> > extent permitted by law. Type "show copying" and "show warranty" for
> > details. This GDB was configured as "x86_64-pc-linux-gnu"...
> > Using host libthread_db library "/lib/libthread_db.so.1".
> > (gdb) run -D
> > Starting program: /usr/bin/router -D
> > Failed to read a valid object file image from memory.
> > >>> NAD OP nad_new: 0xa56f210
> > ..........
> > sx (io.c:194) tag 9 event 2 data 0xa584540
> > Mon Mar 17 13:21:49 2008 router.c:526 reading from 9
> > Mon Mar 17 13:21:49 2008 router.c:584 read 71 bytes
> > sx (io.c:210) passed 71 read bytes
> > sx (chain.c:93) calling io read chain
> > sx (io.c:234) decoded read data (71 bytes): <auth
> > xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechanism='DIGEST-MD5'/>
> > >>> NAD OP nad_new: 0xa5851c0
> > >>> NAD OP nad_add_namespace: 0xa5851c0
> > >>> NAD OP nad_find_scoped_namespace: 0xa5851c0
> > >>> NAD OP nad_add_namespace: 0xa5851c0
> > >>> NAD OP nad_find_scoped_namespace: 0xa5851c0
> > >>> NAD OP nad_append_elem: 0xa5851c0
> > >>> NAD OP nad_append_attr: 0xa5851c0
> > >>> NAD OP nad_print: 0xa5851c0
> > sx (io.c:89) completed nad: <auth
> > xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechanism='DIGEST-MD5'/>
> > sx (chain.c:119) calling nad read chain
> > >>> NAD OP nad_find_attr: 0xa5851c0
> > sx (sasl_gsasl.c:291) auth request from client (mechanism=DIGEST-MD5)
> > sx (sasl_gsasl.c:334) sasl context initialised for 9
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x00002e5b54672715 in ?? ()
> > (gdb) where
> > #0 0x00002e5b54672715 in ?? ()
> > #1 0x0000000000000001 in ?? ()
> > #2 0x00000d8f0a4385ad in ?? ()
> > #3 0x0000000000000007 in ?? ()
> > #4 0x00000d8f0a5852c0 in ?? ()
> > #5 0x00000071ffffffff in ?? ()
> > #6 0x00000d8f00000000 in ?? ()
> > #7 0x0000000000000000 in ?? ()
> > ========== END ==========
> >
> >
> > Since my original message, I've been trying to run it after adding
> > some puts() commands throughout the source, and I think the first
> > problem is here:
> > ========== CODE (sx/sasl_gsasl.c: 340-400)==========
> > } else {
> > puts("NON-ANON");
> > /* decode and process */
> > _sx_sasl_decode(in, inlen, &buf, &buflen);
> > puts(buf);
> > puts("SASL_DECODE");
> > }
> > ret = gsasl_step(sd, buf, buflen, &out, (size_t *) &outlen);
> > puts("GSASL_STEP");
> > if(ret != GSASL_OK && ret != GSASL_NEEDS_MORE) {
> > puts("NOT NEEDS MORE");
> > _sx_debug(ZONE, "gsasl_step failed, no sasl for this conn; (%d): %s",
> > ret, gsasl_strerror(ret));
> > _sx_nad_write(s, _sx_sasl_failure(s, _sasl_err_MALFORMED_REQUEST), 0);
> > puts("STARTFREE");
> > if(out != NULL) free(out);
> > if(buf != NULL) free(buf);
> > puts("ENDFREE");
> > return;
> > }
> > }
> >
> > else {
> > /* decode and process */
> > _sx_sasl_decode(in, inlen, &buf, &buflen);
> > if(!sd) {
> > _sx_debug(ZONE, "response send before auth request enabling mechanism
> > (decoded: %.*s)", buflen, buf);
> > _sx_nad_write(s, _sx_sasl_failure(s, _sasl_err_MECH_TOO_WEAK), 0);
> > if(buf != NULL) free(buf);
> > return;
> > }
> > _sx_debug(ZONE, "response from client (decoded: %.*s)", buflen, buf);
> > ret = gsasl_step(sd, buf, buflen, &out, (size_t *) &outlen);
> > }
> >
> > puts("0:FREE BUF");
> > if(buf != NULL) free(buf);
> > puts("0:FREED BUFF");
> > ========== CONSOLE ==========
> > sx (io.c:234) decoded read data (71 bytes):
> > sx (io.c:89) completed nad:
> > sx (chain.c:119) calling nad read chain
> > sx (sasl_gsasl.c:291) auth request from client (mechanism=DIGEST-MD5)
> > sx (sasl_gsasl.c:334) sasl context initialised for 6
> > SASL CONTEXT INIT
> > VOID SD
> > NON-ANON
> >
> > SASL_DECODE
> > GSASL_STEP
> > 0:FREE BUF
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x000031b7b4783715 in ?? ()
> > ========== END ==========
> > Why would a free() cause a segfault?
> >
> > - Neil
> >
> >
> >
> > On Mon, Mar 17, 2008 at 11:16 AM, Joël Bohnes
> > <[EMAIL PROTECTED]> wrote:
> > > On Mon, 17 Mar 2008 10:16:51 -0700
> > > "Kenji Miyamoto" <[EMAIL PROTECTED]> wrote:
> > >
> > > Hi Neil
> > >
> > > I'm sorry but the gdb backtrace is not really holpefull because the
> > > binary doesn't contain any debug information. You have to tell gcc
> > > that you want to include debug information in the binary - if you
> > > do so you'll have specific information at which point the program
> > > segfaults.
> > >
> > > Gentoo has a really nice guide to show how to make good backtraces:
> > > http://www.gentoo.org/proj/en/qa/backtraces.xml
> > >
> > > To make it short, please do the following things to get a good
> > > backtrace:
> > > *Edit your make.conf and add '-ggdb' to your CFLAGS.
> > >
> > > *Recompile jabberd the following way: 'FEATURES=nostrip emerge
> > > jabberd2'
> > >
> > > *Remove the '-ggdb' from your CFLAGS because you don't want your
> > > other applications to be built with debug information.
> > >
> > > If you did so, please send a new backtrace using gdb.
> > >
> > > ~Shino
> > >
> > >
> > >
> > > > Hello everyone,
> > > >
> > > > After running just fine for months, Jabberd2's router somehow
> > > > started to crash within the sasl_gsasl.c file. I ran the router
> > > > under gdb with debug output turned on (-D). I'm not quite sure
> > > > what else I can provide, other than this is Gentoo's Jabberd2
> > > > version 2.1.21 using PostgreSQL 8.2.6, and fails regardless of
> > > > my chosen CFLAGS. What could be the cause of the segfaults?
> > > >
> > > > - Neil
> > > >
> > > > ========== OUTPUT ==========
> > > >
> > > > sx (io.c:234) decoded read data (71 bytes): <auth
> > > > xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechanism='DIGEST-MD5'/>
> > > > >>> NAD OP nad_new: 0xc832be10
> > > > >>> NAD OP nad_add_namespace: 0xc832be10
> > > > >>> NAD OP nad_find_scoped_namespace: 0xc832be10
> > > > >>> NAD OP nad_add_namespace: 0xc832be10
> > > > >>> NAD OP nad_find_scoped_namespace: 0xc832be10
> > > > >>> NAD OP nad_append_elem: 0xc832be10
> > > > >>> NAD OP nad_append_attr: 0xc832be10
> > > > >>> NAD OP nad_print: 0xc832be10
> > > > sx (io.c:89) completed nad: <auth
> > > > xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechanism='DIGEST-MD5'/>
> > > > sx (chain.c:119) calling nad read chain
> > > > >>> NAD OP nad_find_attr: 0xc832be10
> > > > sx (sasl_gsasl.c:291) auth request from client
> > > > (mechanism=DIGEST-MD5) sx (sasl_gsasl.c:334) sasl context
> > > > initialised for 9
> > > >
> > > > Program received signal SIGSEGV, Segmentation fault.
> > > > 0x00002d46e72f1715 in ?? ()
> > > > (gdb) where
> > > > #0 0x00002d46e72f1715 in ?? ()
> > > > #1 0x0000000000000001 in ?? ()
> > > > #2 0x000004f5c81db5ad in ?? ()
> > > > #3 0x0000000000000008 in ?? ()
> > > > #4 0x000004f5c832bf10 in ?? ()
> > > > #5 0x00000071ffffffff in ?? ()
> > > > #6 0x000004f500000000 in ?? ()
> > > > #7 0x0000000000000000 in ?? ()
> > > >
> > >
> >
>
--
To unsubscribe send a mail to [EMAIL PROTECTED]
