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Fix /proc/<pid>/cmdline and environ #15

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Fix /proc/<pid>/cmdline and environ #15

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32 changes: 32 additions & 0 deletions criu/pie/restorer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1435,6 +1435,26 @@ static ssize_t mmap_image(int fd, const struct iovec *iov, int iovcnt,
return mmaped;
}

static void anonymize_range(const char *name, unsigned long start, unsigned long end, bool executable) {
unsigned long anon;
size_t size;
size = end - start + (start & (PAGE_SIZE - 1));
size = ((size - 1) & PAGE_MASK) + PAGE_SIZE;
anon = sys_mmap(NULL, size, PROT_READ | PROT_WRITE | (executable ? PROT_EXEC : 0),
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (IS_ERR((void *) anon)) {
pr_err("sys_mmap(%s) failed with %d\n", name, -(int) anon);
} else {
unsigned long target, to;
target = start & PAGE_MASK;
memcpy((void *) anon, (void *) target, size);
to = sys_mremap(anon, size, size, MREMAP_MAYMOVE | MREMAP_FIXED, target);
if (to != target) {
pr_err("sys_mremap(%s) failed with %d\n", name, -(int) to);
}
}
}

/*
* The main routine to restore task via sigreturn.
* This one is very special, we never return there
Expand Down Expand Up @@ -1812,6 +1832,18 @@ long __export_restore_task(struct task_restore_args *args)
if (ret)
goto core_restore_end;

/*
* When args and env are mmapped from a file, /proc/<pid>/cmdline and /proc/<pid>/environ
* will be empty. Therefore we have to mmap+memcpy+mremap
*/
if (args->mmap_page_image && args->mm.mm_arg_start != args->mm.mm_arg_end) {
anonymize_range("args", args->mm.mm_arg_start, args->mm.mm_arg_end, false);
}
/* We might be anonymizing the pages twice but this is simple enough */
if (args->mmap_page_image && args->mm.mm_env_start != args->mm.mm_env_end) {
anonymize_range("env", args->mm.mm_env_start, args->mm.mm_env_end, false);
}

/* SELinux (1) process context needs to be set before creating threads. */
if (args->lsm_type == LSMTYPE__SELINUX) {
/* Only for SELinux */
Expand Down
4 changes: 3 additions & 1 deletion include/common/arch/aarch64/asm/page.h
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,6 @@ static inline unsigned page_shift(void)
* page_size() across sources (as it may differ on aarch64).
*/
#define PAGE_SIZE page_size()
#define PAGE_MASK (~(PAGE_SIZE - 1))
#define PAGE_SHIFT page_shift()

#define PAGE_PFN(addr) ((addr) / PAGE_SIZE)
Expand All @@ -41,4 +40,7 @@ extern unsigned page_size(void);
#define PAGE_SIZE page_size()

#endif /* CR_NOGLIBC */

#define PAGE_MASK (~(PAGE_SIZE - 1))

#endif /* __CR_ASM_PAGE_H__ */