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infect.c
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infect.c
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#include <inttypes.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/mman.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/seccomp.h>
#include "log.h"
#include "common/bug.h"
#include "common/xmalloc.h"
#include "common/lock.h"
#include "common/page.h"
#include <compel/plugins/std/syscall-codes.h>
#include <compel/plugins/std/asm/syscall-types.h>
#include "uapi/compel/plugins/std/syscall.h"
#include "asm/infect-types.h"
#include "asm/sigframe.h"
#include "infect.h"
#include "ptrace.h"
#include "infect-rpc.h"
#include "infect-priv.h"
#include "infect-util.h"
#include "rpc-pie-priv.h"
#include "infect-util.h"
#define __sys(foo) foo
#define __sys_err(ret) (-errno)
#include "common/scm.h"
#include "common/scm-code.c"
#ifndef UNIX_PATH_MAX
#define UNIX_PATH_MAX (sizeof(struct sockaddr_un) - (size_t)((struct sockaddr_un *)0)->sun_path)
#endif
#define PARASITE_STACK_SIZE (16 << 10)
#ifndef SECCOMP_MODE_DISABLED
#define SECCOMP_MODE_DISABLED 0
#endif
static int prepare_thread(int pid, struct thread_ctx *ctx);
static inline void close_safe(int *pfd)
{
if (*pfd > -1) {
close(*pfd);
*pfd = -1;
}
}
static int parse_pid_status(int pid, struct seize_task_status *ss, void *data)
{
char aux[128];
FILE *f;
sprintf(aux, "/proc/%d/status", pid);
f = fopen(aux, "r");
if (!f)
return -1;
ss->ppid = -1; /* Not needed at this point */
ss->seccomp_mode = SECCOMP_MODE_DISABLED;
while (fgets(aux, sizeof(aux), f)) {
if (!strncmp(aux, "State:", 6)) {
ss->state = aux[7];
continue;
}
if (!strncmp(aux, "Seccomp:", 8)) {
if (sscanf(aux + 9, "%d", &ss->seccomp_mode) != 1)
goto err_parse;
continue;
}
if (!strncmp(aux, "ShdPnd:", 7)) {
if (sscanf(aux + 7, "%llx", &ss->shdpnd) != 1)
goto err_parse;
continue;
}
if (!strncmp(aux, "SigPnd:", 7)) {
if (sscanf(aux + 7, "%llx", &ss->sigpnd) != 1)
goto err_parse;
continue;
}
if (!strncmp(aux, "SigBlk:", 7)) {
if (sscanf(aux + 7, "%llx", &ss->sigblk) != 1)
goto err_parse;
continue;
}
}
fclose(f);
return 0;
err_parse:
fclose(f);
return -1;
}
int compel_stop_task(int pid)
{
int ret;
struct seize_task_status ss = {};
ret = compel_interrupt_task(pid);
if (ret == 0)
ret = compel_wait_task(pid, -1, parse_pid_status, NULL, &ss, NULL);
return ret;
}
int compel_interrupt_task(int pid)
{
int ret;
ret = ptrace(PTRACE_SEIZE, pid, NULL, 0);
if (ret) {
/*
* ptrace API doesn't allow to distinguish
* attaching to zombie from other errors.
* All errors will be handled in compel_wait_task().
*/
pr_warn("Unable to interrupt task: %d (%s)\n", pid, strerror(errno));
return ret;
}
/*
* If we SEIZE-d the task stop it before going
* and reading its stat from proc. Otherwise task
* may die _while_ we're doing it and we'll have
* inconsistent seize/state pair.
*
* If task dies after we seize it but before we
* do this interrupt, we'll notice it via proc.
*/
ret = ptrace(PTRACE_INTERRUPT, pid, NULL, NULL);
if (ret < 0) {
pr_warn("SEIZE %d: can't interrupt task: %s\n", pid, strerror(errno));
if (ptrace(PTRACE_DETACH, pid, NULL, NULL))
pr_perror("Unable to detach from %d", pid);
}
return ret;
}
static int skip_sigstop(int pid, int nr_signals)
{
int i, status, ret;
/*
* 1) SIGSTOP is queued, but isn't handled yet:
* SGISTOP can't be blocked, so we need to wait when the kernel
* handles this signal.
*
* Otherwise the process will be stopped immediately after
* starting it.
*
* 2) A seized task was stopped:
* PTRACE_SEIZE doesn't affect signal or group stop state.
* Currently ptrace reported that task is in stopped state.
* We need to start task again, and it will be trapped
* immediately, because we sent PTRACE_INTERRUPT to it.
*/
for (i = 0; i < nr_signals; i++) {
ret = ptrace(PTRACE_CONT, pid, 0, 0);
if (ret) {
pr_perror("Unable to start process");
return -1;
}
ret = wait4(pid, &status, __WALL, NULL);
if (ret < 0) {
pr_perror("SEIZE %d: can't wait task", pid);
return -1;
}
if (!WIFSTOPPED(status)) {
pr_err("SEIZE %d: task not stopped after seize\n", pid);
return -1;
}
}
return 0;
}
#define SIG_MASK(sig) (1ULL << ((sig)-1))
#define SIG_IN_MASK(sig, mask) ((sig) > 0 && (sig) <= SIGMAX && (SIG_MASK(sig) & (mask)))
#define SUPPORTED_STOP_MASK ((1ULL << (SIGSTOP - 1)) | (1ULL << (SIGTSTP - 1)))
static inline int sig_stop(int sig)
{
return SIG_IN_MASK(sig, SUPPORTED_STOP_MASK);
}
int compel_parse_stop_signo(int pid)
{
siginfo_t si;
if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &si) < 0) {
pr_perror("SEIZE %d: can't parse stopped siginfo", pid);
return -1;
}
return si.si_signo;
}
/*
* This routine seizes task putting it into a special
* state where we can manipulate the task via ptrace
* interface, and finally we can detach ptrace out of
* of it so the task would not know if it was saddled
* up with someone else.
*/
int compel_wait_task(int pid, int ppid, int (*get_status)(int pid, struct seize_task_status *, void *),
void (*free_status)(int pid, struct seize_task_status *, void *), struct seize_task_status *ss,
void *data)
{
siginfo_t si;
int status, nr_stopsig;
int ret = 0, ret2, wait_errno = 0;
/*
* It's ugly, but the ptrace API doesn't allow to distinguish
* attaching to zombie from other errors. Thus we have to parse
* the target's /proc/pid/stat. Sad, but parse whatever else
* we might need at that early point.
*/
try_again:
ret = wait4(pid, &status, __WALL, NULL);
if (ret < 0) {
/*
* wait4() can expectedly fail only in a first time
* if a task is zombie. If we are here from try_again,
* this means that we are tracing this task.
*
* So here we can be only once in this function.
*/
wait_errno = errno;
}
ret2 = get_status(pid, ss, data);
if (ret2)
goto err;
if (ret < 0 || WIFEXITED(status) || WIFSIGNALED(status)) {
if (ss->state != 'Z') {
if (pid == getpid())
pr_err("The criu itself is within dumped tree.\n");
else
pr_err("Unseizable non-zombie %d found, state %c, err %d/%d\n", pid, ss->state, ret,
wait_errno);
return -1;
}
if (ret < 0)
return COMPEL_TASK_ZOMBIE;
else
return COMPEL_TASK_DEAD;
}
if ((ppid != -1) && (ss->ppid != ppid)) {
pr_err("Task pid reused while suspending (%d: %d -> %d)\n", pid, ppid, ss->ppid);
goto err;
}
if (!WIFSTOPPED(status)) {
pr_err("SEIZE %d: task not stopped after seize\n", pid);
goto err;
}
ret = ptrace(PTRACE_GETSIGINFO, pid, NULL, &si);
if (ret < 0) {
pr_perror("SEIZE %d: can't read signfo", pid);
goto err;
}
if (PTRACE_SI_EVENT(si.si_code) != PTRACE_EVENT_STOP) {
/*
* Kernel notifies us about the task being seized received some
* event other than the STOP, i.e. -- a signal. Let the task
* handle one and repeat.
*/
if (ptrace(PTRACE_CONT, pid, NULL, (void *)(unsigned long)si.si_signo)) {
pr_perror("Can't continue signal handling, aborting");
goto err;
}
if (free_status)
free_status(pid, ss, data);
goto try_again;
}
if (ptrace(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACESYSGOOD)) {
pr_perror("Unable to set PTRACE_O_TRACESYSGOOD for %d", pid);
return -1;
}
if (ss->seccomp_mode != SECCOMP_MODE_DISABLED && ptrace_suspend_seccomp(pid) < 0)
goto err;
/*
* FIXME(issues/1429): parasite code contains instructions that trigger
* SIGTRAP to stop at certain points. In such cases, the kernel sends a
* force SIGTRAP that can't be ignored and if it is blocked, the kernel
* resets its signal handler to a default one and unblocks it. It means
* that if we want to save the origin signal handler, we need to run a
* parasite code with the unblocked SIGTRAP.
*/
if ((ss->sigpnd | ss->shdpnd) & (1 << (SIGTRAP - 1))) {
pr_err("Can't dump the %d thread with a pending SIGTRAP.\n", pid);
goto err;
}
nr_stopsig = 0;
if (SIG_IN_MASK(SIGSTOP, ss->sigpnd))
nr_stopsig++;
if (SIG_IN_MASK(SIGSTOP, ss->shdpnd))
nr_stopsig++;
if (SIG_IN_MASK(SIGTSTP, ss->sigpnd) && !SIG_IN_MASK(SIGTSTP, ss->sigblk))
nr_stopsig++;
if (SIG_IN_MASK(SIGTSTP, ss->shdpnd) && !SIG_IN_MASK(SIGTSTP, ss->sigblk))
nr_stopsig++;
if (sig_stop(si.si_signo))
nr_stopsig++;
if (nr_stopsig) {
if (skip_sigstop(pid, nr_stopsig)) {
/*
* Make sure that the task is stopped by a supported stop signal and
* send it again to restore task state before criu intervention.
*/
if (sig_stop(si.si_signo))
kill(pid, si.si_signo);
else
kill(pid, SIGSTOP);
goto err;
}
return COMPEL_TASK_STOPPED;
}
if (si.si_signo == SIGTRAP)
return COMPEL_TASK_ALIVE;
else {
pr_err("SEIZE %d: unsupported stop signal %d\n", pid, si.si_signo);
goto err;
}
err:
if (ptrace(PTRACE_DETACH, pid, NULL, NULL))
pr_perror("Unable to detach from %d", pid);
return -1;
}
int compel_resume_task(pid_t pid, int orig_st, int st)
{
return compel_resume_task_sig(pid, orig_st, st, SIGSTOP);
}
int compel_resume_task_sig(pid_t pid, int orig_st, int st, int stop_signo)
{
int ret = 0;
pr_debug("\tUnseizing %d into %d\n", pid, st);
if (st == COMPEL_TASK_DEAD) {
kill(pid, SIGKILL);
return 0;
} else if (st == COMPEL_TASK_STOPPED) {
/*
* Task might have had STOP in queue. We detected such
* guy as COMPEL_TASK_STOPPED, but cleared signal to run
* the parasite code. Thus after detach the task will become
* running. That said -- STOP everyone regardless of
* the initial state.
*/
kill(pid, SIGSTOP);
} else if (st == COMPEL_TASK_ALIVE) {
/*
* Same as in the comment above -- there might be a
* task with STOP in queue that would get lost after
* detach, so stop it again.
*/
if (orig_st == COMPEL_TASK_STOPPED) {
/*
* Check that stop_signo contain supported stop signal.
* If it isn't, then send SIGSTOP. It makes sense in the case
* when we get COMPEL_TASK_STOPPED from old image,
* where stop_signo was not yet supported.
*/
if (sig_stop(stop_signo))
kill(pid, stop_signo);
else
kill(pid, SIGSTOP);
}
} else {
pr_err("Unknown final state %d\n", st);
ret = -1;
}
if (ptrace(PTRACE_DETACH, pid, NULL, NULL)) {
pr_perror("Unable to detach from %d", pid);
return -1;
}
return ret;
}
static int gen_parasite_saddr(struct sockaddr_un *saddr, int key)
{
int sun_len;
saddr->sun_family = AF_UNIX;
snprintf(saddr->sun_path, UNIX_PATH_MAX, "X/crtools-pr-%d-%" PRIx64, key, compel_run_id);
sun_len = SUN_LEN(saddr);
*saddr->sun_path = '\0';
return sun_len;
}
static int prepare_tsock(struct parasite_ctl *ctl, pid_t pid, struct parasite_init_args *args)
{
int ssock = -1;
socklen_t sk_len;
struct sockaddr_un addr;
pr_info("Putting tsock into pid %d\n", pid);
args->h_addr_len = gen_parasite_saddr(&args->h_addr, getpid());
ssock = ctl->ictx.sock;
sk_len = sizeof(addr);
if (ssock == -1) {
pr_err("No socket in ictx\n");
goto err;
}
if (getsockname(ssock, (struct sockaddr *)&addr, &sk_len) < 0) {
pr_perror("Unable to get name for a socket");
return -1;
}
if (sk_len == sizeof(addr.sun_family)) {
if (bind(ssock, (struct sockaddr *)&args->h_addr, args->h_addr_len) < 0) {
pr_perror("Can't bind socket");
goto err;
}
if (listen(ssock, 1)) {
pr_perror("Can't listen on transport socket");
goto err;
}
}
/* Check a case when parasite can't initialize a command socket */
if (ctl->ictx.flags & INFECT_FAIL_CONNECT)
args->h_addr_len = gen_parasite_saddr(&args->h_addr, getpid() + 1);
/*
* Set to -1 to prevent any accidental misuse. The
* only valid user of it is accept_tsock().
*/
ctl->tsock = -ssock;
return 0;
err:
close_safe(&ssock);
return -1;
}
static int setup_child_handler(struct parasite_ctl *ctl)
{
struct sigaction sa = {
.sa_sigaction = ctl->ictx.child_handler,
.sa_flags = SA_SIGINFO | SA_RESTART,
};
sigemptyset(&sa.sa_mask);
sigaddset(&sa.sa_mask, SIGCHLD);
if (sigaction(SIGCHLD, &sa, NULL)) {
pr_perror("Unable to setup SIGCHLD handler");
return -1;
}
return 0;
}
static int restore_child_handler(struct parasite_ctl *ctl)
{
if (sigaction(SIGCHLD, &ctl->ictx.orig_handler, NULL)) {
pr_perror("Unable to setup SIGCHLD handler");
return -1;
}
return 0;
}
static int parasite_run(pid_t pid, int cmd, unsigned long ip, void *stack, user_regs_struct_t *regs,
struct thread_ctx *octx)
{
k_rtsigset_t block;
ksigfillset(&block);
/*
* FIXME(issues/1429): SIGTRAP can't be blocked, otherwise its handler
* will be reset to the default one.
*/
ksigdelset(&block, SIGTRAP);
if (ptrace(PTRACE_SETSIGMASK, pid, sizeof(k_rtsigset_t), &block)) {
pr_perror("Can't block signals for %d", pid);
goto err_sig;
}
parasite_setup_regs(ip, stack, regs);
if (ptrace_set_regs(pid, regs)) {
pr_perror("Can't set registers for %d", pid);
goto err_regs;
}
if (ptrace(cmd, pid, NULL, NULL)) {
pr_perror("Can't run parasite at %d", pid);
goto err_cont;
}
return 0;
err_cont:
if (ptrace_set_regs(pid, &octx->regs))
pr_perror("Can't restore regs for %d", pid);
err_regs:
if (ptrace(PTRACE_SETSIGMASK, pid, sizeof(k_rtsigset_t), &octx->sigmask))
pr_perror("Can't restore sigmask for %d", pid);
err_sig:
return -1;
}
static int restore_thread_ctx(int pid, struct thread_ctx *ctx, bool restore_ext_regs)
{
int ret = 0;
if (ptrace_set_regs(pid, &ctx->regs)) {
pr_perror("Can't restore registers (pid: %d)", pid);
ret = -1;
}
if (restore_ext_regs && compel_set_task_ext_regs(pid, &ctx->ext_regs))
ret = -1;
if (ptrace(PTRACE_SETSIGMASK, pid, sizeof(k_rtsigset_t), &ctx->sigmask)) {
pr_perror("Can't block signals");
ret = -1;
}
return ret;
}
/* we run at @regs->ip */
static int parasite_trap(struct parasite_ctl *ctl, pid_t pid, user_regs_struct_t *regs, struct thread_ctx *octx,
bool may_use_extended_regs)
{
siginfo_t siginfo;
int status;
int ret = -1;
/*
* Most ideas are taken from Tejun Heo's parasite thread
* https://code.google.com/p/ptrace-parasite/
*/
if (wait4(pid, &status, __WALL, NULL) != pid) {
pr_perror("Waited pid mismatch (pid: %d)", pid);
goto err;
}
if (!WIFSTOPPED(status)) {
pr_err("Task is still running (pid: %d, status: 0x%x)\n", pid, status);
goto err;
}
if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo)) {
pr_perror("Can't get siginfo (pid: %d)", pid);
goto err;
}
if (ptrace_get_regs(pid, regs)) {
pr_perror("Can't obtain registers (pid: %d)", pid);
goto err;
}
if (WSTOPSIG(status) != SIGTRAP || siginfo.si_code != ARCH_SI_TRAP) {
pr_debug("** delivering signal %d si_code=%d\n", siginfo.si_signo, siginfo.si_code);
pr_err("Unexpected %d task interruption, aborting\n", pid);
goto err;
}
/*
* We've reached this point if int3 is triggered inside our
* parasite code. So we're done.
*/
ret = 0;
err:
if (restore_thread_ctx(pid, octx, may_use_extended_regs))
ret = -1;
return ret;
}
int compel_execute_syscall(struct parasite_ctl *ctl, user_regs_struct_t *regs, const char *code_syscall)
{
pid_t pid = ctl->rpid;
int err;
uint8_t code_orig[BUILTIN_SYSCALL_SIZE];
/*
* Inject syscall instruction and remember original code,
* we will need it to restore original program content.
*/
memcpy(code_orig, code_syscall, sizeof(code_orig));
if (ptrace_swap_area(pid, (void *)ctl->ictx.syscall_ip, (void *)code_orig, sizeof(code_orig))) {
pr_err("Can't inject syscall blob (pid: %d)\n", pid);
return -1;
}
err = parasite_run(pid, PTRACE_CONT, ctl->ictx.syscall_ip, 0, regs, &ctl->orig);
if (!err)
err = parasite_trap(ctl, pid, regs, &ctl->orig, false);
if (ptrace_poke_area(pid, (void *)code_orig, (void *)ctl->ictx.syscall_ip, sizeof(code_orig))) {
pr_err("Can't restore syscall blob (pid: %d)\n", ctl->rpid);
err = -1;
}
return err;
}
int compel_run_at(struct parasite_ctl *ctl, unsigned long ip, user_regs_struct_t *ret_regs)
{
user_regs_struct_t regs = ctl->orig.regs;
int ret;
ret = parasite_run(ctl->rpid, PTRACE_CONT, ip, 0, ®s, &ctl->orig);
if (!ret)
ret = parasite_trap(ctl, ctl->rpid, ret_regs ? ret_regs : ®s, &ctl->orig, false);
return ret;
}
static int accept_tsock(struct parasite_ctl *ctl)
{
int sock;
int ask = -ctl->tsock; /* this '-' is explained above */
sock = accept(ask, NULL, 0);
if (sock < 0) {
pr_perror("Can't accept connection to the transport socket");
close(ask);
return -1;
}
ctl->tsock = sock;
return 0;
}
static int parasite_init_daemon(struct parasite_ctl *ctl)
{
struct parasite_init_args *args;
pid_t pid = ctl->rpid;
user_regs_struct_t regs;
struct ctl_msg m = {};
*ctl->cmd = PARASITE_CMD_INIT_DAEMON;
args = compel_parasite_args(ctl, struct parasite_init_args);
args->sigframe = (uintptr_t)ctl->rsigframe;
args->log_level = compel_log_get_loglevel();
#ifdef ARCH_HAS_LONG_PAGES
args->page_size = PAGE_SIZE;
#endif
futex_set(&args->daemon_connected, 0);
if (prepare_tsock(ctl, pid, args))
goto err;
/* after this we can catch parasite errors in chld handler */
if (setup_child_handler(ctl))
goto err;
regs = ctl->orig.regs;
if (parasite_run(pid, PTRACE_CONT, ctl->parasite_ip, ctl->rstack, ®s, &ctl->orig))
goto err;
futex_wait_while_eq(&args->daemon_connected, 0);
if (futex_get(&args->daemon_connected) != 1) {
errno = -(int)futex_get(&args->daemon_connected);
pr_perror("Unable to connect a transport socket");
goto err;
}
if (accept_tsock(ctl) < 0)
goto err;
if (compel_util_send_fd(ctl, ctl->ictx.log_fd))
goto err;
pr_info("Wait for parasite being daemonized...\n");
if (parasite_wait_ack(ctl->tsock, PARASITE_CMD_INIT_DAEMON, &m)) {
pr_err("Can't switch parasite %d to daemon mode %d\n", pid, m.err);
goto err;
}
ctl->sigreturn_addr = (void *)(uintptr_t)args->sigreturn_addr;
ctl->daemonized = true;
pr_info("Parasite %d has been switched to daemon mode\n", pid);
return 0;
err:
return -1;
}
static int parasite_start_daemon(struct parasite_ctl *ctl)
{
pid_t pid = ctl->rpid;
struct infect_ctx *ictx = &ctl->ictx;
user_fpregs_struct_t ext_regs;
/*
* Get task registers before going daemon, since the
* compel_get_task_regs() needs to call ptrace on _stopped_ task,
* while in daemon it is not such.
*/
if (compel_get_task_regs(pid, &ctl->orig.regs, &ext_regs, ictx->save_regs, ictx->regs_arg, ictx->flags)) {
pr_err("Can't obtain regs for thread %d\n", pid);
return -1;
}
if (__compel_arch_fetch_thread_area(pid, &ctl->orig)) {
pr_err("Can't get thread area of %d\n", pid);
return -1;
}
if (ictx->make_sigframe(ictx->regs_arg, ctl->sigframe, ctl->rsigframe, &ctl->orig.sigmask))
return -1;
if (parasite_setup_shstk(ctl, &ext_regs))
return -1;
if (parasite_init_daemon(ctl))
return -1;
return 0;
}
static int parasite_mmap_exchange(struct parasite_ctl *ctl, unsigned long size, int remote_prot)
{
int fd;
ctl->remote_map = remote_mmap(ctl, NULL, size, remote_prot, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
if (!ctl->remote_map) {
pr_err("Can't allocate memory for parasite blob (pid: %d)\n", ctl->rpid);
return -1;
}
ctl->map_length = round_up(size, page_size());
fd = ctl->ictx.open_proc(ctl->rpid, O_RDWR, "map_files/%lx-%lx", (long)ctl->remote_map,
(long)ctl->remote_map + ctl->map_length);
if (fd < 0)
return -1;
ctl->local_map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FILE, fd, 0);
close(fd);
if (ctl->local_map == MAP_FAILED) {
ctl->local_map = NULL;
pr_perror("Can't map remote parasite map");
return -1;
}
return 0;
}
static void parasite_memfd_close(struct parasite_ctl *ctl, int fd)
{
bool compat = !compel_mode_native(ctl);
long ret;
int err;
err = compel_syscall(ctl, __NR(close, compat), &ret, fd, 0, 0, 0, 0, 0);
if (err || ret)
pr_err("Can't close memfd\n");
}
static int parasite_memfd_exchange(struct parasite_ctl *ctl, unsigned long size, int remote_prot)
{
void *where = (void *)ctl->ictx.syscall_ip + BUILTIN_SYSCALL_SIZE;
bool compat_task = !compel_mode_native(ctl);
uint8_t orig_code[MEMFD_FNAME_SZ] = MEMFD_FNAME;
pid_t pid = ctl->rpid;
long sret = -ENOSYS;
int ret, fd, lfd, remote_flags;
if (ctl->ictx.flags & INFECT_NO_MEMFD)
return 1;
BUILD_BUG_ON(sizeof(orig_code) < sizeof(long));
if (ptrace_swap_area(pid, where, (void *)orig_code, sizeof(orig_code))) {
pr_err("Can't inject memfd args (pid: %d)\n", pid);
return -1;
}
ret = compel_syscall(ctl, __NR(memfd_create, compat_task), &sret, (unsigned long)where, 0, 0, 0, 0, 0);
if (ptrace_poke_area(pid, orig_code, where, sizeof(orig_code))) {
fd = (int)sret;
if (fd >= 0)
parasite_memfd_close(ctl, fd);
pr_err("Can't restore memfd args (pid: %d)\n", pid);
return -1;
}
if (ret < 0)
return ret;
fd = (int)sret;
if (fd == -ENOSYS)
return 1;
if (fd < 0) {
errno = -fd;
pr_perror("Can't create memfd in victim");
return fd;
}
ctl->map_length = round_up(size, page_size());
lfd = ctl->ictx.open_proc(ctl->rpid, O_RDWR, "fd/%d", fd);
if (lfd < 0)
goto err_cure;
if (ftruncate(lfd, ctl->map_length) < 0) {
pr_perror("Fail to truncate memfd for parasite");
goto err_cure;
}
remote_flags = MAP_FILE | MAP_SHARED;
if (ctl->ictx.remote_map_addr){
remote_flags |= MAP_FIXED_NOREPLACE;
}
ctl->remote_map = remote_mmap(ctl, (void *)ctl->ictx.remote_map_addr, size, remote_prot, remote_flags, fd, 0);
if (!ctl->remote_map) {
pr_err("Can't rmap memfd for parasite blob\n");
goto err_curef;
}
ctl->local_map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FILE, lfd, 0);
if (ctl->local_map == MAP_FAILED) {
ctl->local_map = NULL;
pr_perror("Can't lmap memfd for parasite blob");
goto err_curef;
}
parasite_memfd_close(ctl, fd);
close(lfd);
pr_info("Set up parasite blob using memfd\n");
return 0;
err_curef:
close(lfd);
err_cure:
parasite_memfd_close(ctl, fd);
return -1;
}
void compel_relocs_apply(void *mem, void *vbase, struct parasite_blob_desc *pbd)
{
compel_reloc_t *elf_relocs = pbd->hdr.relocs;
size_t nr_relocs = pbd->hdr.nr_relocs;
size_t i, j;
void **got = mem + pbd->hdr.got_off;
/*
* parasite_service() reads the value of __export_parasite_service_args_ptr.
* The reason it is set here is that semantically, we are doing a symbol
* resolution on parasite_service_args, and it turns out to be relocatable.
*/
*(void **)(mem + pbd->hdr.args_ptr_off) = vbase + pbd->hdr.args_off;
#ifdef CONFIG_MIPS
compel_relocs_apply_mips(mem, vbase, pbd);
#else
for (i = 0, j = 0; i < nr_relocs; i++) {
if (elf_relocs[i].type & COMPEL_TYPE_LONG) {
long *where = mem + elf_relocs[i].offset;
if (elf_relocs[i].type & COMPEL_TYPE_GOTPCREL) {
int *value = (int *)where;
int rel;
got[j] = vbase + elf_relocs[i].value;
rel = (unsigned)((void *)&got[j] - (void *)mem) - elf_relocs[i].offset +
elf_relocs[i].addend;
*value = rel;
j++;
} else
*where = elf_relocs[i].value + elf_relocs[i].addend + (unsigned long)vbase;
} else if (elf_relocs[i].type & COMPEL_TYPE_INT) {
int *where = (mem + elf_relocs[i].offset);
*where = elf_relocs[i].value + elf_relocs[i].addend + (unsigned long)vbase;
} else
BUG();
}
#endif
}
long remote_mprotect(struct parasite_ctl *ctl, void *addr, size_t len, int prot)
{
long ret;
int err;
bool compat_task = !user_regs_native(&ctl->orig.regs);
err = compel_syscall(ctl, __NR(mprotect, compat_task), &ret, (unsigned long)addr, len, prot, 0, 0, 0);
if (err < 0) {
pr_err("compel_syscall for mprotect failed\n");
return -1;
}
return ret;
}
static int compel_map_exchange(struct parasite_ctl *ctl, unsigned long size)
{
int ret, remote_prot;
if (ctl->pblob.hdr.data_off)
remote_prot = PROT_READ | PROT_EXEC;
else
remote_prot = PROT_READ | PROT_WRITE | PROT_EXEC;
ret = parasite_memfd_exchange(ctl, size, remote_prot);
if (ret == 1) {
pr_info("MemFD parasite doesn't work, goto legacy mmap\n");
ret = parasite_mmap_exchange(ctl, size, remote_prot);
if (ret)
return ret;
}
if (!ctl->pblob.hdr.data_off)
return 0;
ret = remote_mprotect(ctl, ctl->remote_map + ctl->pblob.hdr.data_off, size - ctl->pblob.hdr.data_off,
PROT_READ | PROT_WRITE);
if (ret)
pr_err("remote_mprotect failed\n");
return ret;
}
int compel_infect_no_daemon(struct parasite_ctl *ctl, unsigned long nr_threads, unsigned long args_size)
{
int ret;
unsigned long p, map_exchange_size, parasite_size = 0;
if (ctl->pblob.parasite_type != COMPEL_BLOB_CHEADER)
goto err;
if (ctl->ictx.log_fd < 0)
goto err;
if (!arch_can_dump_task(ctl))
goto err;
/*
* Inject a parasite engine. Ie allocate memory inside alien
* space and copy engine code there. Then re-map the engine
* locally, so we will get an easy way to access engine memory
* without using ptrace at all.
*/
/*
* The parasite memory layout is the following: