
Bochs पर Linux कर्नेल डीबगिंग के लिए उपकरण (प्रतीकों, नेटिव Bochs डीबगर और IDA PRO सहित)
Bochs पर Linux कर्नेल डीबगिंग के लिए उपकरण (इसमें symbols, native Bochs debugger और IDA PRO शामिल हैं)


नीचे दिए गए चरणों का पालन करें:
डिबग कर्नेल इमेज पर बस nm कमांड का उपयोग करें, उदाहरण के लिए Debian:
1- dbg इमेज इंस्टॉल करें
root@debian# apt-get install linux-image-$(uname -r)-dbg
2- जाँचें कि nm dbg इमेज पर काम करता है या नहीं:
dreg@debian# nm /usr/lib/debug/boot/vmlinux-$(uname -r) | tail
ffffffff8207d7c0 d zswap_same_filled_pages_enabled
ffffffff8262b54c b zswap_stored_pages
ffffffff8262b420 b zswap_trees
ffffffff81225df0 t zswap_update_total_size
ffffffff81226a50 t zswap_writeback_entry
ffffffff8262b538 b zswap_written_back_pages
ffffffff81c41fb8 r zswap_zpool_ops
ffffffff8207d7e0 d zswap_zpool_param_ops
3- linsymtobch.py के लिए एक मान्य आउटपुट फ़ाइल बनाएँ:
dreg@debian# nm /usr/lib/debug/boot/vmlinux-$(uname -r) > nm_output.txt
इसके अलावा आप अन्य प्रकार के उपकरणों का उपयोग/संयोजन कर सकते हैं, अधिक संकेतों के लिए इस रिपॉजिटरी को देखें:
https://github.com/therealdreg/linux_kernel_debug_disassemble_ida_vmware
nm शैली की आउटपुट फ़ाइल को Bochs syms फ़ाइल में बदलने के लिए linsymtobch.py का उपयोग करें:
python linsymbtobch.py symbol_file.txt output_bochs_syms.txt [letter 1] [letter 2] [letter 3] .... [--verbose]
उदाहरण:
./linsymtobch.py nm_output.txt output_bochs_syms.txt
Output:
https://github.com/therealdreg/bochs_linux_kernel_debugging
-
MIT LICENSE Copyright <2020>
David Reguera Garcia aka Dreg - [email protected]
http://www.fr33project.org/ - https://github.com/therealdreg
usage: python linsymbtobch.py symbol_file.txt output_bochs_syms.txt [letter 1] [letter 2] [letter 3] .... [--verbose]
where letters can be empty for all symbols or a combination:
If lowercase, the symbol is local; if uppercase, the symbol is global (external).
------------------------------------
"A" The symbol's value is absolute, and will not be changed by further linking.
"B" "b" The symbol is in the uninitialized data section (known as BSS ).
"C" The symbol is common. Common symbols are uninitialized data. When linking, multiple common symbols may appear with the same name. If the symbol is defined anywhere, the common symbols are treated as undefined references.
"D" "d" The symbol is in the initialized data section.
"G" "g" The symbol is in an initialized data section for small objects. Some object file formats permit more efficient access to small data objects, such as a global int variable as opposed to a large global array.
"i" For PE format files this indicates that the symbol is in a section specific to the implementation of DLLs. For ELF format files this indicates that the symbol is an indirect function. This is a GNU extension to the standard set of ELF symbol types. It indicates a symbol which if referenced by a relocation does not evaluate to its address, but instead must be invoked at runtime. The runtime execution will then return the value to be used in the relocation.
"N" The symbol is a debugging symbol.
"p" The symbols is in a stack unwind section.
"R" "r" The symbol is in a read only data section.
"S" "s" The symbol is in an uninitialized data section for small objects.
"T" "t" The symbol is in the text (code) section.
"U" The symbol is undefined.
"u" The symbol is a unique global symbol. This is a GNU extension to the standard set of ELF symbol bindings. For such a symbol the dynamic linker will make sure that in the entire process there is just one symbol with this name and type in use.
"V" "v" The symbol is a weak object. When a weak defined symbol is linked with a normal defined symbol, the normal defined symbol is used with no error. When a weak undefined symbol is linked and the symbol is not defined, the value of the weak symbol becomes zero with no error. On some systems, uppercase indicates that a default value has been specified.
"W" "w" The symbol is a weak symbol that has not been specifically tagged as a weak object symbol. When a weak defined symbol is linked with a normal defined symbol, the normal defined symbol is used with no error. When a weak undefined symbol is linked and the symbol is not defined, the value of the symbol is determined in a system-specific manner without error. On some systems, uppercase indicates that a default value has been specified.
"-" The symbol is a stabs symbol in an a.out object file. In this case, the next values printed are the stabs other field, the stabs desc field, and the stab type. Stabs symbols are used to hold debugging information.
"?" The symbol type is unknown, or object file format specific.
------------------------------------
0xffffffff81412a30 T_aa_af_perm
0xffffffff813ff4f0 T_aa_alloc_profile
0xffffffff8140c420 T_aa_alloc_proxy
0xffffffff82c71f0d T_aa_alloc_root_ns
0xffffffff81409e20 T_aa_alloc_secid
0xffffffff813f7bc0 T_aa_apply_modes_to_perms
0xffffffff813f6030 T_aa_audit
0xffffffff8140a210 T_aa_audit_file
0xffffffff813f6010 T_aa_audit_msg
...
done!
total symbols written: 115131
total letters written: A B D R T V W a b d r t
total letters found: A B D R T V W a b d r t
कुछ symbols फ़िल्टर करने का उदाहरण:
./linsymtobch.py nm_output.txt output_bochs_syms.txt T V d
जनरेट की गई फ़ाइल को Bochs डीबगर में "ldsym global" से लोड करें, उदाहरण:
ldsym global "C:\Users\leno\Desktop\bochs_linux_kernel_debugging\output_bochs_syms.txt"
हो गया! Bochs डीबगर पर कुछ कमांड चलाकर देखें कि symbols काम करते हैं या नहीं:

"C:\Program Files\IDA Pro 7.7\cfg\dbg_bochs.cfg" संपादित करें
BOCHSDBG = "C:\\Users\\leno\\Desktop\\Bochs-pruebas\\bochs\\bochs.exe";
BOCHSRC = "C:\\Users\\leno\\Desktop\\Bochs-pruebas\\bochs\\.bochsrc";
IDA पर जाएँ .....
Debugger -> Run -> Local Bochs Debugger
एप्लिकेशन:
C:\Users\leno\Desktop\Bochs-pruebas\bochs\.bochsrc
Debug Options पर क्लिक करें -> Set specific options चुनें -> Disk image चुनें
इस रिपॉजिटरी से ida_load_names.py डाउनलोड करें:
https://github.com/therealdreg/symseghelper
IDA PRO खोलें, Bochs डीबग सत्र शुरू करें और File -> Script File पर जाएँ
ida_load_names.py चुनें, यह स्क्रिप्ट आपसे जनरेट की गई Bochs symbol फ़ाइल पूछती है
हो गया!
उसके बाद आप Native Bochs Debugger (जो IDA PRO के अंदर चल रहा है) पर भी symbols लोड कर सकते हैं। बस IDA कमांड लाइन में Bochs चुनें और "ldsym global" निष्पादित करें
Bochs symbols के साथ IDA PRO (ida_load_names.py) + symbols के साथ Bochs native debugger (ldsym global), दोनों दुनिया का सर्वश्रेष्ठ:

चेतावनी: आपका अपना Bochs Instrumentation IDA PRO Local Bochs पर समस्याएँ पैदा कर सकता है
Bochs और IDA Pro के लिए symbols (PDB फ़ाइलें) के साथ Windows डीबगिंग हेतु सहायक स्क्रिप्ट। User mode <--> kernel mode के लिए बहुत उपयोगी:
VMware + GDB stub पर IDA Pro के साथ Linux कर्नेल डीबगिंग हेतु सहायक स्क्रिप्ट (कुछ symbols सहायक सहित):
Bochs Debugging Format के समर्थन सहित PDB Symbols डंप करें (wine समर्थन के साथ):
native Bochs डीबगर पर IDA Pro के साथ Windows कर्नेल डीबगिंग हेतु सहायक स्क्रिप्ट: