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-rw-r--r--src/hook/inject.c412
1 files changed, 412 insertions, 0 deletions
diff --git a/src/hook/inject.c b/src/hook/inject.c
new file mode 100644
index 0000000..34c078c
--- /dev/null
+++ b/src/hook/inject.c
@@ -0,0 +1,412 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/user.h>
+#include <sys/wait.h>
+#include <sys/ptrace.h>
+#include <sys/mman.h>
+#include <dlfcn.h>
+#include <unistd.h>
+#include <elf.h>
+
+#include "inject.h"
+#include "memory.h"
+#include "module.h"
+#include "arch.h"
+
+#define Elf64W(type) Elf64_ ## type
+#define Elf32W(type) Elf32_ ## type
+
+#define Elf64Ehdr Elf64W(Ehdr)
+#define Elf32Ehdr Elf32W(Ehdr)
+
+#define Elf64Shdr Elf64W(Shdr)
+#define Elf32Shdr Elf32W(Shdr)
+
+#define Elf64Sym Elf64W(Sym)
+#define Elf32Sym Elf32W(Sym)
+
+static uintptr_t getSymbolOffset(const char* elf_path, const char* symbol_name)
+{
+ unsigned char bits = getElfBits(elf_path);
+
+ FILE* fd = fopen(elf_path, "rb");
+ fseek(fd, 0, SEEK_END);
+ size_t elf_size = (size_t) ftell(fd);
+ rewind(fd);
+
+ char* elf_body = malloc(elf_size);
+ fread(elf_body, 1, elf_size, fd);
+ fclose(fd);
+
+ if (bits == 64)
+ {
+ Elf64Ehdr* header = (Elf64Ehdr*)elf_body;
+
+ Elf64Shdr* section = (Elf64Shdr*)(elf_body + header->e_shoff);
+ Elf64Shdr* symtab_section = NULL;
+ for (uintptr_t i = 0; i <= header->e_shnum; i++)
+ {
+ if (i == header->e_shnum)
+ return 0;
+
+ if (section[i].sh_type == SHT_SYMTAB)
+ {
+ symtab_section = section+i;
+ break;
+ }
+ }
+
+ Elf64Sym* symtab = (Elf64Sym*)(elf_body + symtab_section->sh_offset);
+ size_t symbol_num = symtab_section->sh_size / symtab_section->sh_entsize;
+ char *symbol_names = (char *)(elf_body + section[symtab_section->sh_link].sh_offset);
+
+ for (size_t j = 0; j < symbol_num; ++j)
+ {
+ char* name = symbol_names + symtab[j].st_name;
+ size_t symbol_name_len = strlen(symbol_name);
+ if (strncmp(name, symbol_name, symbol_name_len))
+ continue;
+ if (name[symbol_name_len] != '\0' && name[symbol_name_len] != '@')
+ continue;
+
+ if (symtab[j].st_value > 0)
+ {
+ uintptr_t value = symtab[j].st_value;
+ free(elf_body);
+ return value;
+ }
+ }
+ }
+ else if (bits == 32)
+ {
+ Elf32Ehdr* header = (Elf32Ehdr*)elf_body;
+
+ Elf32Shdr* section = (Elf32Shdr*)(elf_body + header->e_shoff);
+ Elf32Shdr* symtab_section = NULL;
+ for (uintptr_t i = 0; i <= header->e_shnum; i++)
+ {
+ if (i == header->e_shnum)
+ return 0;
+
+ if (section[i].sh_type == SHT_SYMTAB)
+ {
+ symtab_section = section+i;
+ break;
+ }
+ }
+
+ Elf32Sym* symtab = (Elf32Sym*)(elf_body + symtab_section->sh_offset);
+ size_t symbol_num = symtab_section->sh_size / symtab_section->sh_entsize;
+ char *symbol_names = (char *)(elf_body + section[symtab_section->sh_link].sh_offset);
+
+ for (size_t j = 0; j < symbol_num; ++j)
+ {
+ char* name = symbol_names + symtab[j].st_name;
+ size_t symbol_name_len = strlen(symbol_name);
+ if (strncmp(name, symbol_name, symbol_name_len))
+ continue;
+ if (name[symbol_name_len] != '\0' && name[symbol_name_len] != '@')
+ continue;
+
+ if (symtab[j].st_value > 0)
+ {
+ uintptr_t value = symtab[j].st_value;
+ free(elf_body);
+ return value;
+ }
+ }
+ }
+
+ free(elf_body);
+
+ return 0;
+}
+
+void* inject_syscall(
+ pid_t pid,
+ uintptr_t syscall_n,
+ void* arg0,
+ void* arg1,
+ void* arg2,
+ void* arg3,
+ void* arg4,
+ void* arg5
+){
+ void* ret = (void*)-1;
+ int status;
+ struct user_regs_struct old_regs, regs;
+ void* injection_addr = (void*)-1;
+
+ //This buffer is our payload, which will run a syscall properly on x86/x64
+ unsigned char injection_buf[] =
+ {
+ 0xff, 0xff, // placerholder
+ /* these nops are here because
+ * we're going to write memory using
+ * ptrace, and it always writes the size
+ * of a word, which means we have to make
+ * sure the buffer is long enough
+ */
+ 0x90, //nop
+ 0x90, //nop
+ 0x90, //nop
+ 0x90, //nop
+ 0x90, //nop
+ 0x90 //nop
+ };
+
+ unsigned char bits = getProcessBits(pid);
+ if (bits == 64)
+ {
+ //syscall
+ injection_buf[0] = 0x0f;
+ injection_buf[1] = 0x05;
+ }
+ else if (bits == 32)
+ {
+ //int80 (syscall)
+ injection_buf[0] = 0xcd;
+ injection_buf[1] = 0x80;
+ }
+ else
+ {
+ return NULL;
+ }
+
+ //As ptrace will always write a uintptr_t, let's make sure we're using proper buffers
+ uintptr_t old_data;
+ uintptr_t injection_buffer;
+ memcpy(&injection_buffer, injection_buf, sizeof(injection_buffer));
+
+ //Attach to process using 'PTRACE_ATTACH'
+ ptrace(PTRACE_ATTACH, pid, NULL, NULL);
+ wait(&status);
+
+ /* Get the current registers using 'PTRACE_GETREGS' so that
+ * we can restore the execution later
+ * and also modify the bytes of EIP/RIP
+ */
+
+ ptrace(PTRACE_GETREGS, pid, NULL, &old_regs);
+ regs = old_regs;
+
+ //Now, let's set up the registers that will be injected into the tracee
+
+#if defined(__i386__)
+ regs.eax = (uintptr_t)syscall_n;
+ regs.ebx = (uintptr_t)arg0;
+ regs.ecx = (uintptr_t)arg1;
+ regs.edx = (uintptr_t)arg2;
+ regs.esi = (uintptr_t)arg3;
+ regs.edi = (uintptr_t)arg4;
+ regs.ebp = (uintptr_t)arg5;
+ injection_addr = (void*)regs.eip;
+#elif defined(__x86_64__)
+ if (bits == 64)
+ {
+ regs.rax = (uintptr_t)syscall_n;
+ regs.rdi = (uintptr_t)arg0;
+ regs.rsi = (uintptr_t)arg1;
+ regs.rdx = (uintptr_t)arg2;
+ regs.r10 = (uintptr_t)arg3;
+ regs.r8 = (uintptr_t)arg4;
+ regs.r9 = (uintptr_t)arg5;
+ injection_addr = (void*)regs.rip;
+ }
+ else if (bits == 32)
+ {
+ regs.rax = (uintptr_t)syscall_n;
+ regs.rbx = (uintptr_t)arg0;
+ regs.rcx = (uintptr_t)arg1;
+ regs.rdx = (uintptr_t)arg2;
+ regs.rsi = (uintptr_t)arg3;
+ regs.rdi = (uintptr_t)arg4;
+ regs.rbp = (uintptr_t)arg5;
+ injection_addr = (void*)regs.rip;
+ }
+#endif
+
+ //Let's store the buffer at EIP/RIP that we're going to modify into 'old_data' using 'PTRACE_PEEKDATA'
+ old_data = (uintptr_t)ptrace(PTRACE_PEEKDATA, pid, injection_addr, NULL);
+
+ //Let's write our payload into the EIP/RIP of the target process using 'PTRACE_POKEDATA'
+ ptrace(PTRACE_POKEDATA, pid, injection_addr, injection_buffer);
+
+ //Let's inject our modified registers into the target process using 'PTRACE_SETREGS'
+ ptrace(PTRACE_SETREGS, pid, NULL, &regs);
+
+ //Let's run a single step in the target process (execute one assembly instruction)
+ ptrace(PTRACE_SINGLESTEP, pid, NULL, NULL);
+ waitpid(pid, &status, WSTOPPED); //Wait for the instruction to run
+
+ //Let's get the registers after the syscall to store the return value
+ ptrace(PTRACE_GETREGS, pid, NULL, &regs);
+#if defined(__i386__)
+ ret = (void*)regs.eax;
+#elif defined(__x86_64__)
+ ret = (void*)regs.rax;
+#endif
+
+ long long ret_int = (long long)ret;
+
+ if (ret_int < 0)
+ fprintf(stderr, "syscall error: %s\n", strerror((int)-ret_int));
+
+ //Let's write the old data at EIP/RIP
+ ptrace(PTRACE_POKEDATA, pid, (void*)injection_addr, old_data);
+
+ //Let's restore the old registers to continue the normal execution
+ ptrace(PTRACE_SETREGS, pid, NULL, &old_regs);
+ ptrace(PTRACE_DETACH, pid, NULL, NULL); //Detach and continue the execution
+
+ return ret;
+}
+
+
+/**
+ * Return values:
+ * 1 already loaded
+ * 2 arch error
+ */
+int load_library(pid_t pid, char* lib_path)
+{
+ /* Let's get the address of the 'libc_dlopen_mode' of the target process
+ * and store it on 'dlopen_ex' by loading the LIBC of the target process
+ * on here and then getting the offset of its own '__libc_dlopen_mode'.
+ * Then we sum this offset to the base of the external LIBC module
+ */
+ struct module_s lib_mod = getModule(pid, lib_path);
+ if (lib_mod.size)
+ return 1;
+
+ struct module_s libc_ex = getModule(pid, "/libc.so");
+ uintptr_t offset = getSymbolOffset(libc_ex.path, "__libc_dlopen_mode");
+
+ // fallback
+ if (!offset)
+ offset = getSymbolOffset(libc_ex.path, "dlopen");
+
+ fprintf(stderr, "%li\n", offset);
+
+ //Get the external '__libc_dlopen_mode' by summing the offset to the libc_ex.base
+ void* dlopen_ex = (void*)((uintptr_t)libc_ex.base + offset);
+
+ freeModule(&libc_ex);
+
+ //--- Now let's go to the injection part
+
+ int status;
+ struct user_regs_struct old_regs, regs;
+ unsigned char inj_buf_x64[] =
+ {
+ /* On 'x64', we dont have to pass anything to the stack, as we're only
+ * using 2 parameters, which will be stored on RDI (library path address) and
+ * RSI (flags, in this case RTLD_LAZY).
+ * This means we just have to call the __libc_dlopen_mode function, which
+ * will be on RAX.
+ */
+
+ 0xFF, 0xD0, //call rax
+ 0xCC, //int3 (SIGTRAP)
+ };
+
+ unsigned char inj_buf_x86[] =
+ {
+ /* We have to pass the parameters to the stack (in reversed order)
+ * The register 'ebx' will store the library path address and the
+ * register 'ecx' will store the flag (RTLD_LAZY)
+ * After pushing the parameters to the stack, we will call EAX, which
+ * will store the address of '__libc_dlopen_mode'
+ */
+ 0x51, //push ecx
+ 0x53, //push ebx
+ 0xFF, 0xD0, //call eax
+ 0xCC, //int3 (SIGTRAP)
+ };
+
+ unsigned char* inj_buf = NULL;
+ size_t sizeof_inj_buf = 0;
+
+ unsigned char bits = getProcessBits(pid);
+ if (bits == 64)
+ {
+ inj_buf = inj_buf_x64;
+ sizeof_inj_buf = sizeof(inj_buf_x64);
+ }
+ else if (bits == 32)
+ {
+ inj_buf = inj_buf_x86;
+ sizeof_inj_buf = sizeof(inj_buf_x86);
+ }
+ else
+ {
+ fprintf(stderr, "Could not figure out what injection buffer to use\n");
+ return 2;
+ }
+
+ //Let's allocate memory for the payload and the library path
+ size_t lib_path_len = strlen(lib_path) + 1;
+ size_t inj_size = sizeof_inj_buf + lib_path_len;
+ void* inj_addr = allocate_memory(pid, inj_size, PROT_EXEC | PROT_READ | PROT_WRITE);
+ void* path_addr = (void*)((uintptr_t)inj_addr + sizeof_inj_buf);
+
+ //Write the memory to our allocated address
+ write_memory(pid, inj_addr, inj_buf, sizeof_inj_buf);
+ write_memory(pid, path_addr, (void*)lib_path, lib_path_len);
+
+ //Attach to the target process
+ ptrace(PTRACE_ATTACH, pid, NULL, NULL);
+ wait(&status);
+
+ //Get the current registers to restore later
+ ptrace(PTRACE_GETREGS, pid, NULL, &old_regs);
+ regs = old_regs;
+
+ //Let's setup the registers according to our payload
+# if defined(__i386__)
+ regs.eax = (long)dlopen_ex;
+ regs.ebx = (long)path_addr;
+ regs.ecx = (long)RTLD_LAZY;
+ regs.eip = (long)inj_addr; //The execution will continue from 'inj_addr' (EIP)
+# elif defined(__x86_64__)
+ if (bits == 64)
+ {
+ regs.rax = (uintptr_t)dlopen_ex;
+ regs.rdi = (uintptr_t)path_addr;
+ regs.rsi = (uintptr_t)RTLD_LAZY;
+ regs.rip = (uintptr_t)inj_addr; //The execution will continue from 'inj_addr' (RIP)
+ }
+ else if (bits == 32)
+ {
+ regs.rax = (uintptr_t)dlopen_ex;
+ regs.rbx = (uintptr_t)path_addr;
+ regs.rcx = (uintptr_t)RTLD_LAZY;
+ regs.rip = (uintptr_t)inj_addr; //The execution will continue from 'inj_addr' (RIP)
+ }
+# endif
+
+ //Inject the modified registers to the target process
+ ptrace(PTRACE_SETREGS, pid, NULL, &regs);
+
+ //Continue the execution
+ ptrace(PTRACE_CONT, pid, NULL, NULL);
+
+ //Wait for the int3 (SIGTRAP) breakpoint
+ waitpid(pid, &status, WSTOPPED);
+
+ //Set back the old registers
+ ptrace(PTRACE_SETREGS, pid, NULL, &old_regs);
+
+ //Detach from the process and continue the execution
+ ptrace(PTRACE_DETACH, pid, NULL, NULL);
+
+ //Deallocate the memory we allocated for the injection buffer and the library path
+ deallocate_memory(pid, inj_addr, inj_size);
+
+ return 0;
+}
+
+
+
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