Index: trunk/src/sstrip.c =================================================================== --- trunk/src/sstrip.c (revision 544) +++ (revision ) @@ -1,538 +1,0 @@ -/* sstrip, version 2.0: Copyright (C) 1999-2001 by Brian Raiter, under the - * GNU General Public License. No warranty. See LICENSE for details. - */ - -/* Modified for portability and 64bit/32bit elf executables, Rainer Wichmann */ - -#include "config.h" - -#include -#include -#include -#include -#include -#include - -#if !defined(__ia64) && !defined(__ia64__) && !defined(__itanium__) && \ - !defined(__alpha) && !defined(__alpha__) && \ - (defined(HAVE_ELF_H) || defined(HAVE_LINUX_ELF_H)) && \ - (defined(__linux__) || defined(__FreeBSD__)) && \ - (defined(__i386__) || defined(__i386) || defined(i386)) - -/* || defined(__sun) || defined(__sun__) || defined(sun) */ - - -#if defined(HAVE_ELF_H) -#include -#else -#include -#endif - -#ifndef TRUE -#define TRUE 1 -#define FALSE 0 -#endif - -#ifndef ELFCLASS32 -#define ELFCLASS32 1 /* 32-bit objects */ -#endif -#ifndef ELFCLASS64 -#define ELFCLASS64 2 /* 64-bit objects */ -#endif - - - -/* The name of the program. - */ -static char const *progname; - -/* The name of the current file. - */ -static char const *filename; - - -/* A simple error-handling function. FALSE is always returned for the - * convenience of the caller. - */ -static int err(char const *errmsg) -{ - fprintf(stderr, "%s: %s: %s\n", progname, filename, errmsg); - return FALSE; -} - -/* A macro for I/O errors: The given error message is used only when - * errno is not set. - */ -#define ferr(msg) (err(errno ? strerror(errno) : (msg))) - -/* readelfheader() reads the ELF header into our global variable, and - * checks to make sure that this is in fact a file that we should be - * munging. - */ -static int readelfheader_32(int fd, Elf32_Ehdr *ehdr) -{ - errno = 0; - if (read(fd, ehdr, sizeof *ehdr) != sizeof *ehdr) - return ferr("missing or incomplete ELF header."); - - /* Check the ELF signature. - */ - if (!(ehdr->e_ident[EI_MAG0] == ELFMAG0 && - ehdr->e_ident[EI_MAG1] == ELFMAG1 && - ehdr->e_ident[EI_MAG2] == ELFMAG2 && - ehdr->e_ident[EI_MAG3] == ELFMAG3)) - return err("missing ELF signature."); - - /* Compare the file's class and endianness with the program's. - */ -#ifdef ELF_DATA - if (ehdr->e_ident[EI_DATA] != ELF_DATA) - return err("ELF file has different endianness."); -#endif - - if (ehdr->e_ident[EI_CLASS] != ELFCLASS32) - return FALSE; - - /* Check the target architecture. - */ -#ifdef ELF_ARCH - if (ehdr->e_machine != ELF_ARCH) - return err("ELF file created for different architecture."); -#endif - - /* Verify the sizes of the ELF header and the program segment - * header table entries. - */ - if (ehdr->e_ehsize != sizeof(Elf32_Ehdr)) - return err("unrecognized ELF header size."); - if (ehdr->e_phentsize != sizeof(Elf32_Phdr)) - return err("unrecognized program segment header size."); - - /* Finally, check the file type. - */ - if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) - return err("not an executable or shared-object library."); - - return TRUE; -} - -static int readelfheader_64(int fd, Elf64_Ehdr *ehdr) -{ - errno = 0; - - if (lseek(fd, 0, SEEK_SET)) - return ferr("could not rewind file"); - - if (read(fd, ehdr, sizeof *ehdr) != sizeof *ehdr) - return ferr("missing or incomplete ELF header."); - - /* Check the ELF signature. - */ - if (!(ehdr->e_ident[EI_MAG0] == ELFMAG0 && - ehdr->e_ident[EI_MAG1] == ELFMAG1 && - ehdr->e_ident[EI_MAG2] == ELFMAG2 && - ehdr->e_ident[EI_MAG3] == ELFMAG3)) - return err("missing ELF signature."); - - /* Compare the file's class and endianness with the program's. - */ -#ifdef ELF_DATA - if (ehdr->e_ident[EI_DATA] != ELF_DATA) - return err("ELF file has different endianness."); -#endif - - if (ehdr->e_ident[EI_CLASS] != ELFCLASS64) - return err("ELF file has different word size."); - - /* Check the target architecture. - */ -#ifdef ELF_ARCH - if (ehdr->e_machine != ELF_ARCH) - return err("ELF file created for different architecture."); -#endif - - /* Verify the sizes of the ELF header and the program segment - * header table entries. - */ - if (ehdr->e_ehsize != sizeof(Elf64_Ehdr)) - return err("unrecognized ELF header size."); - if (ehdr->e_phentsize != sizeof(Elf64_Phdr)) - return err("unrecognized program segment header size."); - - /* Finally, check the file type. - */ - if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) - return err("not an executable or shared-object library."); - - return TRUE; -} - -/* readphdrtable() loads the program segment header table into memory. - */ -static int readphdrtable_32(int fd, Elf32_Ehdr const *ehdr, Elf32_Phdr **phdrs) -{ - size_t size; - - if (!ehdr->e_phoff || !ehdr->e_phnum) - return err("ELF file has no program header table."); - - size = ehdr->e_phnum * sizeof **phdrs; - if (!(*phdrs = calloc(1,size))) - return err("Out of memory!"); - - errno = 0; - if (read(fd, *phdrs, size) != (ssize_t)size) - return ferr("missing or incomplete program segment header table."); - - return TRUE; -} - -static int readphdrtable_64(int fd, Elf64_Ehdr const *ehdr, Elf64_Phdr **phdrs) -{ - size_t size; - - if (!ehdr->e_phoff || !ehdr->e_phnum) - return err("ELF file has no program header table."); - - size = ehdr->e_phnum * sizeof **phdrs; - if (!(*phdrs = calloc(1,size))) - return err("Out of memory!"); - - errno = 0; - if (read(fd, *phdrs, size) != (ssize_t)size) - return ferr("missing or incomplete program segment header table."); - - return TRUE; -} - -/* getmemorysize() determines the offset of the last byte of the file - * that is referenced by an entry in the program segment header table. - * (Anything in the file after that point is not used when the program - * is executing, and thus can be safely discarded.) - */ -static int getmemorysize_32(Elf32_Ehdr const *ehdr, Elf32_Phdr const *phdrs, - unsigned long *newsize) -{ - Elf32_Phdr const *phdr; - unsigned long size, n; - unsigned int i; - - /* Start by setting the size to include the ELF header and the - * complete program segment header table. - */ - size = ehdr->e_phoff + ehdr->e_phnum * sizeof *phdrs; - if (size < sizeof *ehdr) - size = sizeof *ehdr; - - /* Then keep extending the size to include whatever data the - * program segment header table references. - */ - for (i = 0, phdr = phdrs ; i < ehdr->e_phnum ; ++i, ++phdr) { - if (phdr->p_type != PT_NULL) { - n = phdr->p_offset + phdr->p_filesz; - if (n > size) - size = n; - } - } - - *newsize = size; - return TRUE; -} - -static int getmemorysize_64(Elf64_Ehdr const *ehdr, Elf64_Phdr const *phdrs, - unsigned long *newsize) -{ - Elf64_Phdr const *phdr; - unsigned long size, n; - unsigned int i; - - /* Start by setting the size to include the ELF header and the - * complete program segment header table. - */ - size = ehdr->e_phoff + ehdr->e_phnum * sizeof *phdrs; - if (size < sizeof *ehdr) - size = sizeof *ehdr; - - /* Then keep extending the size to include whatever data the - * program segment header table references. - */ - for (i = 0, phdr = phdrs ; i < ehdr->e_phnum ; ++i, ++phdr) { - if (phdr->p_type != PT_NULL) { - n = phdr->p_offset + phdr->p_filesz; - if (n > size) - size = n; - } - } - - *newsize = size; - return TRUE; -} - -/* truncatezeros() examines the bytes at the end of the file's - * size-to-be, and reduces the size to exclude any trailing zero - * bytes. - */ -static int truncatezeros(int fd, unsigned long *newsize) -{ - unsigned char contents[1024]; - unsigned long size, n; - - size = *newsize; - do { - n = sizeof contents; - if (n > size) - n = size; - if (lseek(fd, size - n, SEEK_SET) == (off_t)-1) - return ferr("cannot seek in file."); - if (read(fd, contents, n) != (ssize_t)n) - return ferr("cannot read file contents"); - while (n && !contents[--n]) - --size; - } while (size && !n); - - /* Sanity check. - */ - if (!size) - return err("ELF file is completely blank!"); - - *newsize = size; - return TRUE; -} - -/* modifyheaders() removes references to the section header table if - * it was stripped, and reduces program header table entries that - * included truncated bytes at the end of the file. - */ -static int modifyheaders_32(Elf32_Ehdr *ehdr, Elf32_Phdr *phdrs, - unsigned long newsize) -{ - Elf32_Phdr *phdr; - unsigned int i; - - /* If the section header table is gone, then remove all references - * to it in the ELF header. - */ - if (ehdr->e_shoff >= newsize) { - ehdr->e_shoff = 0; - ehdr->e_shnum = 0; - ehdr->e_shentsize = 0; - ehdr->e_shstrndx = 0; - } - - /* The program adjusts the file size of any segment that was - * truncated. The case of a segment being completely stripped out - * is handled separately. - */ - for (i = 0, phdr = phdrs ; i < ehdr->e_phnum ; ++i, ++phdr) { - if (phdr->p_offset >= newsize) { - phdr->p_offset = newsize; - phdr->p_filesz = 0; - } else if (phdr->p_offset + phdr->p_filesz > newsize) { - phdr->p_filesz = newsize - phdr->p_offset; - } - } - - return TRUE; -} - -static int modifyheaders_64(Elf64_Ehdr *ehdr, Elf64_Phdr *phdrs, - unsigned long newsize) -{ - Elf64_Phdr *phdr; - unsigned int i; - - /* If the section header table is gone, then remove all references - * to it in the ELF header. - */ - if (ehdr->e_shoff >= newsize) { - ehdr->e_shoff = 0; - ehdr->e_shnum = 0; - ehdr->e_shentsize = 0; - ehdr->e_shstrndx = 0; - } - - /* The program adjusts the file size of any segment that was - * truncated. The case of a segment being completely stripped out - * is handled separately. - */ - for (i = 0, phdr = phdrs ; i < ehdr->e_phnum ; ++i, ++phdr) { - if (phdr->p_offset >= newsize) { - phdr->p_offset = newsize; - phdr->p_filesz = 0; - } else if (phdr->p_offset + phdr->p_filesz > newsize) { - phdr->p_filesz = newsize - phdr->p_offset; - } - } - - return TRUE; -} - -/* commitchanges() writes the new headers back to the original file - * and sets the file to its new size. - */ -static int commitchanges_32(int fd, Elf32_Ehdr const *ehdr, Elf32_Phdr *phdrs, - unsigned long newsize) -{ - size_t n; - - /* Save the changes to the ELF header, if any. - */ - if (lseek(fd, 0, SEEK_SET)) - return ferr("could not rewind file"); - errno = 0; - if (write(fd, ehdr, sizeof *ehdr) != sizeof *ehdr) - return err("could not modify file"); - - /* Save the changes to the program segment header table, if any. - */ - if (lseek(fd, ehdr->e_phoff, SEEK_SET) == (off_t)-1) { - err("could not seek in file."); - goto warning; - } - n = ehdr->e_phnum * sizeof *phdrs; - if (write(fd, phdrs, n) != (ssize_t)n) { - err("could not write to file"); - goto warning; - } - - /* Eleventh-hour sanity check: don't truncate before the end of - * the program segment header table. - */ - if (newsize < ehdr->e_phoff + n) - newsize = ehdr->e_phoff + n; - - /* Chop off the end of the file. - */ - if (ftruncate(fd, newsize)) { - err("could not resize file"); - goto warning; - } - - return TRUE; - - warning: - return err("ELF file may have been corrupted!"); -} - -static int commitchanges_64(int fd, Elf64_Ehdr const *ehdr, Elf64_Phdr *phdrs, - unsigned long newsize) -{ - size_t n; - - /* Save the changes to the ELF header, if any. - */ - if (lseek(fd, 0, SEEK_SET)) - return ferr("could not rewind file"); - errno = 0; - if (write(fd, ehdr, sizeof *ehdr) != sizeof *ehdr) - return err("could not modify file"); - - /* Save the changes to the program segment header table, if any. - */ - if (lseek(fd, ehdr->e_phoff, SEEK_SET) == (off_t)-1) { - err("could not seek in file."); - goto warning; - } - n = ehdr->e_phnum * sizeof *phdrs; - if (write(fd, phdrs, n) != (ssize_t)n) { - err("could not write to file"); - goto warning; - } - - /* Eleventh-hour sanity check: don't truncate before the end of - * the program segment header table. - */ - if (newsize < ehdr->e_phoff + n) - newsize = ehdr->e_phoff + n; - - /* Chop off the end of the file. - */ - if (ftruncate(fd, newsize)) { - err("could not resize file"); - goto warning; - } - - return TRUE; - - warning: - return err("ELF file may have been corrupted!"); -} - -/* main() loops over the cmdline arguments, leaving all the real work - * to the other functions. - */ -int main(int argc, char *argv[]) -{ - int fd; - int is_32bit_elf; - Elf32_Ehdr ehdr32; - Elf32_Phdr *phdrs32 = NULL; - Elf64_Ehdr ehdr64; - Elf64_Phdr *phdrs64 = NULL; - unsigned long newsize; - char **arg; - int failures = 0; - - if (argc < 2 || argv[1][0] == '-') { - printf("Usage: sstrip FILE...\n" - "sstrip discards all nonessential bytes from an executable.\n\n" - "Version 2.0 Copyright (C) 2000,2001 Brian Raiter.\n" - "This program is free software, licensed under the GNU\n" - "General Public License. There is absolutely no warranty.\n"); - return EXIT_SUCCESS; - } - - progname = argv[0]; - - for (arg = argv + 1 ; *arg != NULL ; ++arg) { - filename = *arg; - - fd = open(*arg, O_RDWR); - if (fd < 0) { - ferr("can't open"); - ++failures; - continue; - } - - if (readelfheader_32(fd, &ehdr32)) { - is_32bit_elf = TRUE; - } - else if (readelfheader_64(fd, &ehdr64)) { - is_32bit_elf = FALSE; - } - else { - close(fd); - return EXIT_FAILURE; - } - - if (is_32bit_elf) { - if (!(readphdrtable_32(fd, &ehdr32, &phdrs32) && - getmemorysize_32(&ehdr32, phdrs32, &newsize) && - truncatezeros(fd, &newsize) && - modifyheaders_32(&ehdr32, phdrs32, newsize) && - commitchanges_32(fd, &ehdr32, phdrs32, newsize))) - ++failures; - } - else { - if (!(readphdrtable_64(fd, &ehdr64, &phdrs64) && - getmemorysize_64(&ehdr64, phdrs64, &newsize) && - truncatezeros(fd, &newsize) && - modifyheaders_64(&ehdr64, phdrs64, newsize) && - commitchanges_64(fd, &ehdr64, phdrs64, newsize))) - ++failures; - } - - close(fd); - } - - return failures ? EXIT_FAILURE : EXIT_SUCCESS; -} - -#else - -int main() -{ - return (EXIT_SUCCESS); -} - -#endif