Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
zvrba
committed
Apr 1, 2012
1 parent
cffdcb5
commit 9fbf4b5
Showing
4 changed files
with
348 additions
and
348 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,143 +1,143 @@ | ||
| /* | ||
| * File: elfcrypt.c | ||
| * Author: zvrba | ||
| * Created: 2008-04-09 | ||
| * | ||
| * =========================================================================== | ||
| * COPYRIGHT (c) 2008 Zeljko Vrba <zvrba.external@zvrba.net> | ||
| * | ||
| * Permission is hereby granted, free of charge, to any person obtaining a | ||
| * copy of this software and associated documentation files (the "Software"), | ||
| * to deal in the Software without restriction, including without limitation | ||
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, | ||
| * and/or sell copies of the Software, and to permit persons to whom the | ||
| * Software is furnished to do so, subject to the following conditions: | ||
| * | ||
| * The above copyright notice and this permission notice shall be included in | ||
| * all copies or substantial portions of the Software. | ||
| * | ||
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | ||
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | ||
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER | ||
| * DEALINGS IN THE SOFTWARE. | ||
| * =========================================================================== | ||
| */ | ||
| /** | ||
| * @file | ||
| * | ||
| * Encrypt all loadable segments in an ELF file. The key is given on the | ||
| * command-line as a 32-digit hex string (total 128 bits). The ELF file is | ||
| * encrypted with simple ECB scheme just as proof-of-concept. Other modes, | ||
| * such as CTR, are also possible. | ||
| */ | ||
|
|
||
| #include <stdio.h> | ||
| #include <stdlib.h> | ||
| #include <string.h> | ||
| #include "types.h" | ||
| #include "elf.h" | ||
| #include "rc5-16.h" | ||
| #include "util.h" | ||
|
|
||
| static void check_eh_limits(const Elf32_Ehdr*, size_t); | ||
| static void crypt_segment(const struct rc5_key*, char*, Elf32_Phdr*); | ||
|
|
||
| int main(int argc, char **argv) | ||
| { | ||
| struct rc5_key key; | ||
| char *elf; | ||
| size_t elfsz; | ||
| Elf32_Ehdr *eh; | ||
| Elf32_Phdr *ph; | ||
| FILE *out; | ||
| unsigned i, cnt; | ||
|
|
||
| if(argc != 4) { | ||
| fprintf(stderr, "USAGE: %s ELF-IN ELF-OUT HEXKEY\n", argv[0]); | ||
| return 1; | ||
| } | ||
| if(!rc5_convert_key(&key, argv[3])) { | ||
| fprintf(stderr, "can't convert key to internal form\n"); | ||
| return 1; | ||
| } | ||
| rc5_setup(&key); | ||
|
|
||
| read_elf(argv[1], &elf, &elfsz); | ||
| eh = (Elf32_Ehdr*)elf; | ||
| check_eh_limits(eh, elfsz); | ||
|
|
||
| /* Iterate segments, check bounds and encrypt PT_LOAD. */ | ||
| ph = (Elf32_Phdr*)(elf + eh->e_phoff); | ||
| for(i = 0, cnt = 0; i < eh->e_phnum; i++) { | ||
| if(ph->p_type != PT_LOAD) | ||
| continue; | ||
| ++cnt; | ||
| if(ph->p_offset + ph->p_filesz >= elfsz) { | ||
| fprintf(stderr, "input segment %u is out of ELF bounds\n", i); | ||
| exit(1); | ||
| } | ||
| if((ph->p_filesz % RC5_BLOCKSZ) || (ph->p_memsz % RC5_BLOCKSZ)) { | ||
| /* 4 bytes is the cipher block size */ | ||
| fprintf(stderr, "input segment file/memory size is not a multiple of 4\n"); | ||
| exit(1); | ||
| } | ||
| crypt_segment(&key, elf, ph+i); | ||
| } | ||
|
|
||
| if(!cnt) { | ||
| fprintf(stderr, "no PT_LOAD segments found\n"); | ||
| exit(1); | ||
| } | ||
|
|
||
| if(!(out = fopen(argv[2], "w"))) { | ||
| fprintf(stderr, "can't write output\n"); | ||
| exit(1); | ||
| } | ||
| if((fwrite(elf, 1, elfsz, out) != elfsz) || (fclose(out) == EOF)) { | ||
| fprintf(stderr, "output incomplete\n"); | ||
| exit(1); | ||
| } | ||
| return 0; | ||
| } | ||
|
|
||
| static void crypt_segment(const struct rc5_key *pk, char *elf, Elf32_Phdr *ph) | ||
| { | ||
| char *p = elf + ph->p_offset; | ||
| unsigned i; | ||
|
|
||
| for(i = 0; i < ph->p_filesz; i += RC5_BLOCKSZ) | ||
| rc5_ecb_encrypt(pk, p+i, p+i); | ||
| } | ||
|
|
||
| static void check_eh_limits(const Elf32_Ehdr *eh, size_t elfsz) | ||
| { | ||
| if(memcmp(eh->e_ident, "\177ELF", 4) != 0) { | ||
| fprintf(stderr, "input doesn't have the ELF magic\n"); | ||
| exit(1); | ||
| } | ||
| if((eh->e_ident[EI_CLASS] != ELFCLASS32) || | ||
| (eh->e_ident[EI_DATA] != ELFDATA2LSB)) { | ||
| fprintf(stderr, "input isn't LSB/32\n"); | ||
| exit(1); | ||
| } | ||
| if((eh->e_ehsize != sizeof(*eh)) || | ||
| (eh->e_phentsize != sizeof(Elf32_Phdr))) { | ||
| fprintf(stderr, "mismatch between file and program structures\n"); | ||
| exit(1); | ||
| } | ||
| if(eh->e_type != ET_EXEC) { | ||
| fprintf(stderr, "input isn't ET_EXEC\n"); | ||
| exit(1); | ||
| } | ||
| if(!eh->e_phnum) { | ||
| fprintf(stderr, "input has no program headers\n"); | ||
| exit(1); | ||
| } | ||
| if(eh->e_phoff + eh->e_phnum*eh->e_phentsize > elfsz) { | ||
| fprintf(stderr, "invalid bounds of program header table\n"); | ||
| exit(1); | ||
| } | ||
| } | ||
| /* | ||
| * File: elfcrypt.c | ||
| * Author: zvrba | ||
| * Created: 2008-04-09 | ||
| * | ||
| * =========================================================================== | ||
| * COPYRIGHT (c) 2008 Zeljko Vrba <zvrba.external@zvrba.net> | ||
| * | ||
| * Permission is hereby granted, free of charge, to any person obtaining a | ||
| * copy of this software and associated documentation files (the "Software"), | ||
| * to deal in the Software without restriction, including without limitation | ||
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, | ||
| * and/or sell copies of the Software, and to permit persons to whom the | ||
| * Software is furnished to do so, subject to the following conditions: | ||
| * | ||
| * The above copyright notice and this permission notice shall be included in | ||
| * all copies or substantial portions of the Software. | ||
| * | ||
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | ||
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | ||
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER | ||
| * DEALINGS IN THE SOFTWARE. | ||
| * =========================================================================== | ||
| */ | ||
| /** | ||
| * @file | ||
| * | ||
| * Encrypt all loadable segments in an ELF file. The key is given on the | ||
| * command-line as a 32-digit hex string (total 128 bits). The ELF file is | ||
| * encrypted with simple ECB scheme just as proof-of-concept. Other modes, | ||
| * such as CTR, are also possible. | ||
| */ | ||
|
|
||
| #include <stdio.h> | ||
| #include <stdlib.h> | ||
| #include <string.h> | ||
| #include "types.h" | ||
| #include "elf.h" | ||
| #include "rc5-16.h" | ||
| #include "util.h" | ||
|
|
||
| static void check_eh_limits(const Elf32_Ehdr*, size_t); | ||
| static void crypt_segment(const struct rc5_key*, char*, Elf32_Phdr*); | ||
|
|
||
| int main(int argc, char **argv) | ||
| { | ||
| struct rc5_key key; | ||
| char *elf; | ||
| size_t elfsz; | ||
| Elf32_Ehdr *eh; | ||
| Elf32_Phdr *ph; | ||
| FILE *out; | ||
| unsigned i, cnt; | ||
|
|
||
| if(argc != 4) { | ||
| fprintf(stderr, "USAGE: %s ELF-IN ELF-OUT HEXKEY\n", argv[0]); | ||
| return 1; | ||
| } | ||
| if(!rc5_convert_key(&key, argv[3])) { | ||
| fprintf(stderr, "can't convert key to internal form\n"); | ||
| return 1; | ||
| } | ||
| rc5_setup(&key); | ||
|
|
||
| read_elf(argv[1], &elf, &elfsz); | ||
| eh = (Elf32_Ehdr*)elf; | ||
| check_eh_limits(eh, elfsz); | ||
|
|
||
| /* Iterate segments, check bounds and encrypt PT_LOAD. */ | ||
| ph = (Elf32_Phdr*)(elf + eh->e_phoff); | ||
| for(i = 0, cnt = 0; i < eh->e_phnum; i++) { | ||
| if(ph->p_type != PT_LOAD) | ||
| continue; | ||
| ++cnt; | ||
| if(ph->p_offset + ph->p_filesz >= elfsz) { | ||
| fprintf(stderr, "input segment %u is out of ELF bounds\n", i); | ||
| exit(1); | ||
| } | ||
| if((ph->p_filesz % RC5_BLOCKSZ) || (ph->p_memsz % RC5_BLOCKSZ)) { | ||
| /* 4 bytes is the cipher block size */ | ||
| fprintf(stderr, "input segment file/memory size is not a multiple of 4\n"); | ||
| exit(1); | ||
| } | ||
| crypt_segment(&key, elf, ph+i); | ||
| } | ||
|
|
||
| if(!cnt) { | ||
| fprintf(stderr, "no PT_LOAD segments found\n"); | ||
| exit(1); | ||
| } | ||
|
|
||
| if(!(out = fopen(argv[2], "w"))) { | ||
| fprintf(stderr, "can't write output\n"); | ||
| exit(1); | ||
| } | ||
| if((fwrite(elf, 1, elfsz, out) != elfsz) || (fclose(out) == EOF)) { | ||
| fprintf(stderr, "output incomplete\n"); | ||
| exit(1); | ||
| } | ||
| return 0; | ||
| } | ||
|
|
||
| static void crypt_segment(const struct rc5_key *pk, char *elf, Elf32_Phdr *ph) | ||
| { | ||
| char *p = elf + ph->p_offset; | ||
| unsigned i; | ||
|
|
||
| for(i = 0; i < ph->p_filesz; i += RC5_BLOCKSZ) | ||
| rc5_ecb_encrypt(pk, p+i, p+i); | ||
| } | ||
|
|
||
| static void check_eh_limits(const Elf32_Ehdr *eh, size_t elfsz) | ||
| { | ||
| if(memcmp(eh->e_ident, "\177ELF", 4) != 0) { | ||
| fprintf(stderr, "input doesn't have the ELF magic\n"); | ||
| exit(1); | ||
| } | ||
| if((eh->e_ident[EI_CLASS] != ELFCLASS32) || | ||
| (eh->e_ident[EI_DATA] != ELFDATA2LSB)) { | ||
| fprintf(stderr, "input isn't LSB/32\n"); | ||
| exit(1); | ||
| } | ||
| if((eh->e_ehsize != sizeof(*eh)) || | ||
| (eh->e_phentsize != sizeof(Elf32_Phdr))) { | ||
| fprintf(stderr, "mismatch between file and program structures\n"); | ||
| exit(1); | ||
| } | ||
| if(eh->e_type != ET_EXEC) { | ||
| fprintf(stderr, "input isn't ET_EXEC\n"); | ||
| exit(1); | ||
| } | ||
| if(!eh->e_phnum) { | ||
| fprintf(stderr, "input has no program headers\n"); | ||
| exit(1); | ||
| } | ||
| if(eh->e_phoff + eh->e_phnum*eh->e_phentsize > elfsz) { | ||
| fprintf(stderr, "invalid bounds of program header table\n"); | ||
| exit(1); | ||
| } | ||
| } |
Oops, something went wrong.