# 类型 Radare2 supports the C-syntax data types description. Those types are parsed by a C11-compatible parser and stored in the internal SDB, thus are introspectable with `k` command. Most of the related commands are located in `t` namespace: ``` [0x000051c0]> t? | Usage: t # cparse types commands | t List all loaded types | tj List all loaded types as json | t Show type in 'pf' syntax | t* List types info in r2 commands | t- Delete types by its name | t-* Remove all types | tail [filename] Output the last part of files | tc [type.name] List all/given types in C output format | te[?] List all loaded enums | td[?] Load types from string | tf List all loaded functions signatures | tk Perform sdb query | tl[?] Show/Link type to an address | tn[?] [-][addr] manage noreturn function attributes and marks | to - Open cfg.editor to load types | to Load types from C header file | toe [type.name] Open cfg.editor to edit types | tos Load types from parsed Sdb database | tp [addr|varname] cast data at
to and print it (XXX: type can contain spaces) | tpv @ [value] Show offset formatted for given type | tpx Show value for type with specified byte sequence (XXX: type can contain spaces) | ts[?] Print loaded struct types | tu[?] Print loaded union types | tx[f?] Type xrefs | tt[?] List all loaded typedefs ``` Note that the basic (atomic) types are not those from C standard - not `char`, `_Bool`, or `short`. Because those types can be different from one platform to another, radare2 uses `definite` types like as `int8_t` or `uint64_t` and will convert `int` to `int32_t` or `int64_t` depending on the binary or debuggee platform/compiler. Basic types can be listed using `t` command, for the structured types you need to use `ts`, `tu` or `te` for enums: ``` [0x000051c0]> t char char * int int16_t int32_t int64_t int8_t long long long ... ``` ### Loading types There are three easy ways to define a new type: * Directly from the string using `td` command * From the file using `to ` command * Open an `$EDITOR` to type the definitions in place using `to -` ``` [0x000051c0]> "td struct foo {char* a; int b;}" [0x000051c0]> cat ~/radare2-regressions/bins/headers/s3.h struct S1 { int x[3]; int y[4]; int z; }; [0x000051c0]> to ~/radare2-regressions/bins/headers/s3.h [0x000051c0]> ts foo S1 ``` Also note there is a config option to specify include directories for types parsing ``` [0x00000000]> e??~dir.type dir.types: Default path to look for cparse type files [0x00000000]> e dir.types /usr/include ``` ### Printing types Notice below we have used `ts` command, which basically converts the C type description (or to be precise it's SDB representation) into the sequence of `pf` commands. See more about [print format](https://heersin.gitbook.io/radare2/intro-2/print_modes). The `tp` command uses the `pf` string to print all the members of type at the current offset/given address: ``` [0x000051c0]> ts foo pf zd a b [0x000051c0]> tp foo a : 0x000051c0 = 'hello' b : 0x000051cc = 10 [0x000051c0]> tp foo 0x000053c0 a : 0x000053c0 = 'world' b : 0x000053cc = 20 ``` Also, you could fill your own data into the struct and print it using `tpx` command ``` [0x000051c0]> tpx foo 4141414144141414141442001000000 a : 0x000051c0 = AAAAD.....B b : 0x000051cc = 16 ``` ### Linking Types The `tp` command just performs a temporary cast. But if we want to link some address or variable with the chosen type, we can use `tl` command to store the relationship in SDB. ``` [0x000051c0]> tl S1 = 0x51cf [0x000051c0]> tll (S1) x : 0x000051cf = [ 2315619660, 1207959810, 34803085 ] y : 0x000051db = [ 2370306049, 4293315645, 3860201471, 4093649307 ] z : 0x000051eb = 4464399 ``` Moreover, the link will be shown in the disassembly output or visual mode: ``` [0x000051c0 15% 300 /bin/ls]> pd $r @ entry0 ;-- entry0: 0x000051c0 xor ebp, ebp 0x000051c2 mov r9, rdx 0x000051c5 pop rsi 0x000051c6 mov rdx, rsp 0x000051c9 and rsp, 0xfffffffffffffff0 0x000051cd push rax 0x000051ce push rsp (S1) x : 0x000051cf = [ 2315619660, 1207959810, 34803085 ] y : 0x000051db = [ 2370306049, 4293315645, 3860201471, 4093649307 ] z : 0x000051eb = 4464399 0x000051f0 lea rdi, loc._edata ; 0x21f248 0x000051f7 push rbp 0x000051f8 lea rax, loc._edata ; 0x21f248 0x000051ff cmp rax, rdi 0x00005202 mov rbp, rsp ``` Once the struct is linked, radare2 tries to propagate structure offset in the function at current offset, to run this analysis on whole program or at any targeted functions after all structs are linked you have `aat` command: ``` [0x00000000]> aa? | aat [fcn] Analyze all/given function to convert immediate to linked structure offsets (see tl?) ``` Note sometimes the emulation may not be accurate, for example as below : ``` |0x000006da push rbp |0x000006db mov rbp, rsp |0x000006de sub rsp, 0x10 |0x000006e2 mov edi, 0x20 ; "@" |0x000006e7 call sym.imp.malloc ; void *malloc(size_t size) |0x000006ec mov qword [local_8h], rax |0x000006f0 mov rax, qword [local_8h] ``` The return value of `malloc` may differ between two emulations, so you have to set the hint for return value manually using `ahr` command, so run `tl` or `aat` command after setting up the return value hint. ``` [0x000006da]> ah? | ahr val set hint for return value of a function ``` ### Structure Immediates There is one more important aspect of using types in radare2 - using `aht` you can change the immediate in the opcode to the structure offset. Lets see a simple example of \[R]SI-relative addressing ``` [0x000052f0]> pd 1 0x000052f0 mov rax, qword [rsi + 8] ; [0x8:8]=0 ``` Here `8` - is some offset in the memory, where `rsi` probably holds some structure pointer. Imagine that we have the following structures ``` [0x000052f0]> "td struct ms { char b[8]; int member1; int member2; };" [0x000052f0]> "td struct ms1 { uint64_t a; int member1; };" [0x000052f0]> "td struct ms2 { uint16_t a; int64_t b; int member1; };" ``` Now we need to set the proper structure member offset instead of `8` in this instruction. At first, we need to list available types matching this offset: ``` [0x000052f0]> ahts 8 ms.member1 ms1.member1 ``` Note, that `ms2` is not listed, because it has no members with offset `8`. After listing available options we can link it to the chosen offset at the current address: ``` [0x000052f0]> aht ms1.member1 [0x000052f0]> pd 1 0x000052f0 488b4608 mov rax, qword [rsi + ms1.member1] ; [0x8:8]=0 ``` ### Managing enums * Printing all fields in enum using `te` command ``` [0x00000000]> "td enum Foo {COW=1,BAR=2};" [0x00000000]> te Foo COW = 0x1 BAR = 0x2 ``` * Finding matching enum member for given bitfield and vice-versa ``` [0x00000000]> te Foo 0x1 COW [0x00000000]> teb Foo COW 0x1 ``` ## Internal representation To see the internal representation of the types you can use `tk` command: ``` [0x000051c0]> tk~S1 S1=struct struct.S1=x,y,z struct.S1.x=int32_t,0,3 struct.S1.x.meta=4 struct.S1.y=int32_t,12,4 struct.S1.y.meta=4 struct.S1.z=int32_t,28,0 struct.S1.z.meta=0 [0x000051c0]> ``` Defining primitive types requires an understanding of basic `pf` formats, you can find the whole list of format specifier in `pf??`: ``` ----------------------------------------------------- | format | explanation | |---------------------------------------------------| | b | byte (unsigned) | | c | char (signed byte) | | d | 0x%%08x hexadecimal value (4 bytes) | | f | float value (4 bytes) | | i | %%i integer value (4 bytes) | | o | 0x%%08o octal value (4 byte) | | p | pointer reference (2, 4 or 8 bytes) | | q | quadword (8 bytes) | | s | 32bit pointer to string (4 bytes) | | S | 64bit pointer to string (8 bytes) | | t | UNIX timestamp (4 bytes) | | T | show Ten first bytes of buffer | | u | uleb128 (variable length) | | w | word (2 bytes unsigned short in hex) | | x | 0x%%08x hex value and flag (fd @ addr) | | X | show formatted hexpairs | | z | \0 terminated string | | Z | \0 terminated wide string | ----------------------------------------------------- ``` there are basically 3 mandatory keys for defining basic data types: `X=type` `type.X=format_specifier` `type.X.size=size_in_bits` For example, let's define `UNIT`, according to [Microsoft documentation](https://msdn.microsoft.com/en-us/library/windows/desktop/aa383751\(v=vs.85\).aspx#UINT) `UINT` is just equivalent of standard C `unsigned int` (or `uint32_t` in terms of TCC engine). It will be defined as: ``` UINT=type type.UINT=d type.UINT.size=32 ``` Now there is an optional entry: `X.type.pointto=Y` This one may only be used in case of pointer `type.X=p`, one good example is LPFILETIME definition, it is a pointer to `_FILETIME` which happens to be a structure. Assuming that we are targeting only 32-bit windows machine, it will be defined as the following: ``` LPFILETIME=type type.LPFILETIME=p type.LPFILETIME.size=32 type.LPFILETIME.pointto=_FILETIME ``` This last field is not mandatory because sometimes the data structure internals will be proprietary, and we will not have a clean representation for it. There is also one more optional entry: ``` type.UINT.meta=4 ``` This entry is for integration with C parser and carries the type class information: integer size, signed/unsigned, etc. ### Structures Those are the basic keys for structs (with just two elements): ``` X=struct struct.X=a,b struct.X.a=a_type,a_offset,a_number_of_elements struct.X.b=b_type,b_offset,b_number_of_elements ``` The first line is used to define a structure called `X`, the second line defines the elements of `X` as comma separated values. After that, we just define each element info. For example. we can have a struct like this one: ``` struct _FILETIME { DWORD dwLowDateTime; DWORD dwHighDateTime; } ``` assuming we have `DWORD` defined, the struct will look like this ``` _FILETIME=struct struct._FILETIME=dwLowDateTime,dwHighDateTime struct._FILETIME.dwLowDateTime=DWORD,0,0 struct._FILETIME.dwHighDateTime=DWORD,4,0 ``` Note that the number of elements field is used in case of arrays only to identify how many elements are in arrays, other than that it is zero by default. ### Unions Unions are defined exactly like structs the only difference is that you will replace the word `struct` with the word `union`. ### Function prototypes Function prototypes representation is the most detail oriented and the most important one of them all. Actually, this is the one used directly for type matching ``` X=func func.X.args=NumberOfArgs func.x.arg0=Arg_type,arg_name . . . func.X.ret=Return_type func.X.cc=calling_convention ``` It should be self-explanatory. Let's do strncasecmp as an example for x86 arch for Linux machines. According to man pages, strncasecmp is defined as the following: ``` int strcasecmp(const char *s1, const char *s2, size_t n); ``` When converting it into its sdb representation it will look like the following: ``` strcasecmp=func func.strcasecmp.args=3 func.strcasecmp.arg0=char *,s1 func.strcasecmp.arg1=char *,s2 func.strcasecmp.arg2=size_t,n func.strcasecmp.ret=int func.strcasecmp.cc=cdecl ``` Note that the `.cc` part is optional and if it didn't exist the default calling-convention for your target architecture will be used instead. There is one extra optional key ``` func.x.noreturn=true/false ``` This key is used to mark functions that will not return once called, such as `exit` and `_exit`. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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