Full Disclosure mailing list archives
Re: Step-by-step instructions for debugging Cisco IOS using gdb
From: Andrew Farmer <andfarm () gmail com>
Date: Sat, 16 Aug 2008 13:24:20 -0700
On 15 Aug 08, at 11:20, Smiler S wrote:
From: Andy Davis <iosftpexploit_at_googlemail.com<iosftpexploit_at_googlemail.com? Subject=Re:%20Step-by-step%20instructions%20for%20debugging%20Cisco %20IOS%20using%20gdb>> Date: Tue, 12 Aug 2008 22:01:37 +0100Congratulations you are now debugging IOS ;-) One unusual feature, which I have yet to explain is that when the registers are displayed they are all offset by 1 e.g:If a vector variable is stored in a register, gcc writes debug information telling gdb which register the variable is stored in. This mapping is changed between gcc2 & gcc3. Since there isn't anything in the debug output to distinguish code compiled by gcc3 from code compiled by gcc2, there is no way for gdb to know the right map. gdb supports the gcc3 map. If vector code is compiled by gcc2 as in the case of IOS, then the register assignment will be off by 1.
This isn't vector code, though - the whole register map is off. I'm not particularly familiar with IOS, but my guess is the debugging protocol is a little off from what GDB expects. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- Step-by-step instructions for debugging Cisco IOS using gdb Andy Davis (Aug 12)
- <Possible follow-ups>
- Step-by-step instructions for debugging Cisco IOS using gdb Smiler S (Aug 15)
- Re: Step-by-step instructions for debugging Cisco IOS using gdb Andrew Farmer (Aug 16)
- Re: Step-by-step instructions for debugging Cisco IOS using gdb Andy Davis (Aug 16)