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| #include <elf.h> | |
| #include <fcntl.h> | |
| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <sys/mman.h> | |
| // killgdb.c - prevent an elf from being loaded by gdb. | |
| // Jeffrey Crowell <crowell [at] bu [dot] edu> | |
| // | |
| // $ objcopy --only-keep-debug program program.debug | |
| // $ strip program | |
| // $ objcopy --add-gnu-debuglink=program.debug program | |
| // $ ./killgdb program | |
| // $ gdb -q ./program | |
| // Reading symbols from ./program...[1] | |
| // 44513 segmentation fault (core dumped) gdb -q ./program | |
| int filesize(int fd) { return (lseek(fd, 0, SEEK_END)); } | |
| void print_section(Elf64_Shdr *shdr, char *strTab, int shNum, | |
| uint8_t *data) { | |
| int i; | |
| for (i = 0; i < shNum; i++) { | |
| size_t k; | |
| if (!strcmp(".gnu_debuglink", &strTab[shdr[i].sh_name])) { | |
| printf("%02d: %s Offset %lx\n", i, &strTab[shdr[i].sh_name], | |
| shdr[i].sh_offset); | |
| printf("Setting size to zero.\n"); | |
| shdr[i].sh_size = 0; | |
| } | |
| } | |
| } | |
| int main(int ac, char **av) { | |
| void *data; | |
| Elf64_Ehdr *elf; | |
| Elf64_Shdr *shdr; | |
| int fd; | |
| char *strtab; | |
| fd = open(av[1], O_RDWR); | |
| data = mmap(NULL, filesize(fd), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); | |
| elf = (Elf64_Ehdr *)data; | |
| shdr = (Elf64_Shdr *)(data + elf->e_shoff); | |
| strtab = (char *)(data + shdr[elf->e_shstrndx].sh_offset); | |
| print_section(shdr, strtab, elf->e_shnum, (uint8_t*)data); | |
| close(fd); | |
| return 0; | |
| } |
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Segfaults on 32-bit binaries.
sed "s/Elf64/Elf32/g" killgdb.c > killgdb32.cfor a quick fix