RE: 3.90 Segmentation Fault ;-(

["Craig Humphrey" <Craig.Humphrey () chapmantripp com>]

OK, two issues.  Fedora Core 4, just did a yum upgrade (though was lazy
and didn't reboot).
Gcc (GCC) 4.0.1 20050727 (Red Hat 4.0.1-5)
GNU gdb Red Hat Linux (6.3.0.0-1.21rh)

> From configure:
configure: WARNING: linux/netfilter_ipv4/ipchains_core.h: present but
cannot be compiled
configure: WARNING: linux/netfilter_ipv4/ipchains_core.h:     check for
missing prerequisite headers?
configure: WARNING: linux/netfilter_ipv4/ipchains_core.h: see the
Autoconf documentation
configure: WARNING: linux/netfilter_ipv4/ipchains_core.h:     section
"Present But Cannot Be Compiled"
configure: WARNING: linux/netfilter_ipv4/ipchains_core.h: proceeding
with the preprocessor's result
configure: WARNING: linux/netfilter_ipv4/ipchains_core.h: in the future,
the compiler will take recedence
configure: WARNING:     ## ------------------------------------------ ##
configure: WARNING:     ## Report this to the AC_PACKAGE_NAME lists.  ##
configure: WARNING:     ## ------------------------------------------ ##

But that's probably not a biggie.

The main problem is the segfault:

Fired up nmap in emacs/gdb:
(gdb) run -sP 10.9.9.1
warning: cannot close "shared object read from target memory": File in
wrong format
Starting program: /home/craigh/nmap-3.90/nmap -sP 10.9.9.1
Reading symbols from shared object read from target memory...done.
Loaded system supplied DSO at 0xac5000

Starting nmap 3.90 ( http://www.insecure.org/nmap/ ) at 2005-09-09 10:36
NZST
Warning: File ./nmap-services exists, but Nmap is using
/usr/local/share/nmap/nmap-services for security and consistency
reasons.  set NMAPDIR=. to gi\
ve priority to files in your local directory (may affect the other data
files too).

Program received signal SIGSEGV, Segmentation fault.
0x08090cda in convert_code_r (p=0x9072f20) at ./optimize.c:2064
Current language:  auto; currently c

Line 2064 in optimize.c:  off = JF(p)->offset - (p->offset + slen) - 1;
(gdb) p offset
$1 = (struct slist **) 0x90730f0
(gdb) p slen
$2 = 1
(gdb) p p
$3 = (struct block *) 0x9072f20
(gdb) p p->offset + slen
$4 = 3
(gdb) p JF
No symbol "JF" in current context.

Umm to my uneducated (well, it's been a while since I had to debug C
code) mind, that looks to be the problem.  Is JF (and JT) some global or
macro?  They both report "No symbol ... In current context".

Hope that helps someone.

Later'ish
Craig


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