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03cfd8faa7
The binfmt_misc module can calculate the credentials and security token according to the binary instead of to the interpreter if the 'C' flag is enabled. To be able to execute non-readable binaries, this flag implies 'O' flag. When 'O' flag is enabled, bintfmt_misc opens the file for reading and pass the file descriptor to the interpreter. References: linux/Documentation/binfmt_misc.txt ['O' and 'C' description] linux/fs/binfmt_misc.c linux/fs/binfmt_elf.c [ AT_EXECFD usage ] Signed-off-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
182 lines
4.4 KiB
C
182 lines
4.4 KiB
C
/* Code for loading Linux executables. Mostly linux kernel code. */
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "qemu.h"
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#define NGROUPS 32
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/* ??? This should really be somewhere else. */
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abi_long memcpy_to_target(abi_ulong dest, const void *src,
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unsigned long len)
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{
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void *host_ptr;
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host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
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if (!host_ptr)
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return -TARGET_EFAULT;
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memcpy(host_ptr, src, len);
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unlock_user(host_ptr, dest, 1);
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return 0;
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}
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static int count(char ** vec)
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{
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int i;
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for(i = 0; *vec; i++) {
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vec++;
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}
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return(i);
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}
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static int prepare_binprm(struct linux_binprm *bprm)
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{
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struct stat st;
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int mode;
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int retval;
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if(fstat(bprm->fd, &st) < 0) {
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return(-errno);
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}
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mode = st.st_mode;
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if(!S_ISREG(mode)) { /* Must be regular file */
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return(-EACCES);
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}
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if(!(mode & 0111)) { /* Must have at least one execute bit set */
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return(-EACCES);
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}
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bprm->e_uid = geteuid();
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bprm->e_gid = getegid();
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/* Set-uid? */
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if(mode & S_ISUID) {
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bprm->e_uid = st.st_uid;
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}
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/* Set-gid? */
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/*
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* If setgid is set but no group execute bit then this
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* is a candidate for mandatory locking, not a setgid
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* executable.
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*/
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if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
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bprm->e_gid = st.st_gid;
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}
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retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
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if (retval < 0) {
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perror("prepare_binprm");
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exit(-1);
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}
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if (retval < BPRM_BUF_SIZE) {
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/* Make sure the rest of the loader won't read garbage. */
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memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
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}
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return retval;
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}
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/* Construct the envp and argv tables on the target stack. */
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abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
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abi_ulong stringp, int push_ptr)
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{
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CPUArchState *env = thread_cpu->env_ptr;
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TaskState *ts = (TaskState *)env->opaque;
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int n = sizeof(abi_ulong);
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abi_ulong envp;
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abi_ulong argv;
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sp -= (envc + 1) * n;
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envp = sp;
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sp -= (argc + 1) * n;
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argv = sp;
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if (push_ptr) {
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/* FIXME - handle put_user() failures */
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sp -= n;
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put_user_ual(envp, sp);
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sp -= n;
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put_user_ual(argv, sp);
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}
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sp -= n;
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/* FIXME - handle put_user() failures */
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put_user_ual(argc, sp);
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ts->info->arg_start = stringp;
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while (argc-- > 0) {
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/* FIXME - handle put_user() failures */
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put_user_ual(stringp, argv);
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argv += n;
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stringp += target_strlen(stringp) + 1;
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}
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ts->info->arg_end = stringp;
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/* FIXME - handle put_user() failures */
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put_user_ual(0, argv);
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while (envc-- > 0) {
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/* FIXME - handle put_user() failures */
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put_user_ual(stringp, envp);
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envp += n;
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stringp += target_strlen(stringp) + 1;
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}
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/* FIXME - handle put_user() failures */
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put_user_ual(0, envp);
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return sp;
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}
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int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
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struct target_pt_regs * regs, struct image_info *infop,
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struct linux_binprm *bprm)
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{
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int retval;
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int i;
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bprm->p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
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memset(bprm->page, 0, sizeof(bprm->page));
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bprm->fd = fdexec;
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bprm->filename = (char *)filename;
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bprm->argc = count(argv);
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bprm->argv = argv;
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bprm->envc = count(envp);
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bprm->envp = envp;
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retval = prepare_binprm(bprm);
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if(retval>=0) {
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if (bprm->buf[0] == 0x7f
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&& bprm->buf[1] == 'E'
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&& bprm->buf[2] == 'L'
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&& bprm->buf[3] == 'F') {
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retval = load_elf_binary(bprm, regs, infop);
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#if defined(TARGET_HAS_BFLT)
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} else if (bprm->buf[0] == 'b'
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&& bprm->buf[1] == 'F'
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&& bprm->buf[2] == 'L'
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&& bprm->buf[3] == 'T') {
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retval = load_flt_binary(bprm,regs,infop);
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#endif
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} else {
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return -ENOEXEC;
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}
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}
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if(retval>=0) {
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/* success. Initialize important registers */
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do_init_thread(regs, infop);
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return retval;
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}
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/* Something went wrong, return the inode and free the argument pages*/
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for (i=0 ; i<MAX_ARG_PAGES ; i++) {
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g_free(bprm->page[i]);
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}
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return(retval);
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}
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