forked from mirrors/gecko-dev
310043662a
When a binary has a PT_GNU_RELRO segment, the elfhack injected code uses mprotect to add the writable flag to relocated pages before applying relocations, removing it afterwards. To do so, the elfhack program uses the location and size of the PT_GNU_RELRO segment, and adjusts it to be aligned according to the PT_LOAD alignment. The problem here is that the PT_LOAD alignment doesn't necessarily match the actual page alignment, and the resulting mprotect may end up not covering the full extent of what the dynamic linker has protected read-only according to the PT_GNU_RELRO segment. In turn, this can lead to a crash on startup when trying to apply relocations to the still read-only locations. Practically speaking, this doesn't end up being a problem on x86, where the PT_LOAD alignment is usually 4096, which happens to be the page size, but on Debian armhf, it is 64k, while the run time page size can be 4k. --HG-- extra : rebase_source : 5ac7356f685d87c1628727e6c84f7615409c57a5
166 lines
2.9 KiB
C
166 lines
2.9 KiB
C
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifdef DEF
|
|
DEF(This)
|
|
DEF(is)
|
|
DEF(a)
|
|
DEF(test)
|
|
DEF(of)
|
|
DEF(string)
|
|
DEF(array)
|
|
DEF(for)
|
|
DEF(use)
|
|
DEF(with)
|
|
DEF(elfhack)
|
|
DEF(to)
|
|
DEF(see)
|
|
DEF(whether)
|
|
DEF(it)
|
|
DEF(breaks)
|
|
DEF(anything)
|
|
DEF(but)
|
|
DEF(one)
|
|
DEF(needs)
|
|
DEF(quite)
|
|
DEF(some)
|
|
DEF(strings)
|
|
DEF(before)
|
|
DEF(the)
|
|
DEF(program)
|
|
DEF(can)
|
|
DEF(do)
|
|
DEF(its)
|
|
DEF(work)
|
|
DEF(efficiently)
|
|
DEF(Without)
|
|
DEF(enough)
|
|
DEF(data)
|
|
DEF(relocation)
|
|
DEF(sections)
|
|
DEF(are)
|
|
DEF(not)
|
|
DEF(sufficiently)
|
|
DEF(large)
|
|
DEF(and)
|
|
DEF(injected)
|
|
DEF(code)
|
|
DEF(wouldnt)
|
|
DEF(fit)
|
|
DEF(Said)
|
|
DEF(otherwise)
|
|
DEF(we)
|
|
DEF(need)
|
|
DEF(more)
|
|
DEF(words)
|
|
DEF(than)
|
|
DEF(up)
|
|
DEF(here)
|
|
DEF(so)
|
|
DEF(that)
|
|
DEF(relocations)
|
|
DEF(take)
|
|
DEF(significant)
|
|
DEF(bytes)
|
|
DEF(amounts)
|
|
DEF(which)
|
|
DEF(isnt)
|
|
DEF(exactly)
|
|
DEF(easily)
|
|
DEF(achieved)
|
|
DEF(like)
|
|
DEF(this)
|
|
DEF(Actually)
|
|
DEF(I)
|
|
DEF(must)
|
|
DEF(cheat)
|
|
DEF(by)
|
|
DEF(including)
|
|
DEF(these)
|
|
DEF(phrases)
|
|
DEF(several)
|
|
DEF(times)
|
|
|
|
#else
|
|
#pragma GCC visibility push(default)
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
|
|
#define DEF(w) static const char str_ ## w[] = #w;
|
|
#include "test.c"
|
|
#undef DEF
|
|
|
|
const char *strings[] = {
|
|
#define DEF(w) str_ ## w,
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
};
|
|
|
|
/* Create a hole between two zones of relative relocations */
|
|
const int hole[] = {
|
|
42, 42, 42, 42
|
|
};
|
|
|
|
const char *strings2[] = {
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#undef DEF
|
|
};
|
|
|
|
static int ret = 1;
|
|
|
|
int print_status() {
|
|
fprintf(stderr, "%s\n", ret ? "FAIL" : "PASS");
|
|
return ret;
|
|
}
|
|
|
|
/* On ARM, this creates a .tbss section before .init_array, which
|
|
* elfhack could then pick instead of .init_array.
|
|
* Also, when .tbss is big enough, elfhack may wrongfully consider
|
|
* following sections as part of the PT_TLS segment.
|
|
* Finally, gold makes TLS segments end on an aligned virtual address,
|
|
* even when the underlying section ends before that, and elfhack
|
|
* sanity checks may yield an error. */
|
|
__thread int foo;
|
|
__thread long long int bar[512];
|
|
|
|
/* We need a .bss that can hold at least 2 pointers. The static in
|
|
* end_test() plus this variable should do. */
|
|
size_t dummy;
|
|
|
|
void end_test() {
|
|
static size_t count = 0;
|
|
/* Only exit when both constructors have been called */
|
|
if (++count == 2)
|
|
ret = 0;
|
|
}
|
|
|
|
void test() {
|
|
int i = 0, j = 0;
|
|
#define DEF_(a,i,w) \
|
|
if (a[i++] != str_ ## w) return;
|
|
#define DEF(w) DEF_(strings,i,w)
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#undef DEF
|
|
#define DEF(w) DEF_(strings2,j,w)
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#include "test.c"
|
|
#undef DEF
|
|
if (i != sizeof(strings)/sizeof(strings[0]) &&
|
|
j != sizeof(strings2)/sizeof(strings2[0]))
|
|
fprintf(stderr, "WARNING: Test doesn't cover the whole array\n");
|
|
end_test();
|
|
}
|
|
|
|
#pragma GCC visibility pop
|
|
#endif
|