Awesome

ctfquery

Query the CTF for specific information.

Usage

ctfquery [ -s SYM | -t TYPE_ID | -c TYPE_ID | -l LABEL | -v | -h ] <file>

• -s SYM search for a symbol named SYM
• -S TYPE_ID search for all symbols that are of type TYPE_ID
• -t TYPE_ID search for a type identified with TYPE_ID
• -c TYPE_ID solve a typedef chain with the head identified with TYPE_ID
• -l LABEL search for a label with name LABEL
• -v print CTF version of the file
• -h print help message

Build

$ ninja

Dependencies

• libctf
• m_list

Example

... or the tale of the maximal process ID

Grab my hand, we are going for a trip! Say we are, for some reason, totally into finding out about the kernel symbol pid_max which denotes the maximal PID on a system. One way is to look into the source, sure, but what if it is not available and we are stuck with some random black box crash dump? ctfquery to the rescue!

We will start by gently poking the beast:

$ ctfquery -s pid_max /boot/kernel/kernel
776

The first bit of knowledge! The symbol inspection (-s) told us that the type ID of the type associated with the symbol is 776. Only if we could describe a type!

$ ctfquery -t 776 /boot/kernel/kernel
    Kind: typedef
  Ref ID: 775
New name: pid_t

And we could. A type with ID 775 disguised as the pid_t using the typedef sorcery. Sneaky. Let's dive even further!

$ ctfquery -t 775 /boot/kernel/kernel
    Kind: typedef
  Ref ID: 17 
New name: __pid_t

Oh man! This is a serious typedef hell! For how long will we have to follow these links? Luckily, we can solve typedef chains with the -c option for free:

$ ctfquery -c 776 /boot/kernel/kernel
pid_t (776) -> __pid_t (775) -> __int32_t (17) -> int (16)

Finally, some solid info right there, it all seems to boil down to the type with ID 16. You guessed correctly, we're gonna inspect the hell out of it!

$ ctfquery -t 16 /boot/kernel/kernel
   Kind: int
   Name: int
   Size: 32
 Offset: 0
 Signed: yes
Content: number

QED! The symbol pid_max is a 32-bit signed integer. Now go solve the important stuff.

License

2-clause BSD, for more information please see the license.

Author

Daniel Lovasko lovasko@freebsd.org