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x86_64: fix mincore_validate and msync_validate
The calls to mincore() or msync() are not checking for actual accessibility this could lead to SIGSEGV if the address from a mapped page with the PROT_NONE property occurs on the stack. Hence an attempt to write one byte from the checked address to a pipe will fail if the address is not readable.
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Original file line number | Diff line number | Diff line change |
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/* libunwind - a platform-independent unwind library | ||
Copyright (C) 2003-2004 Hewlett-Packard Co | ||
Contributed by David Mosberger-Tang <davidm@hpl.hp.com> | ||
This file is part of libunwind. | ||
Copyright (c) 2003 Hewlett-Packard Co. | ||
Permission is hereby granted, free of charge, to any person obtaining | ||
a copy of this software and associated documentation files (the | ||
"Software"), to deal in the Software without restriction, including | ||
without limitation the rights to use, copy, modify, merge, publish, | ||
distribute, sublicense, and/or sell copies of the Software, and to | ||
permit persons to whom the Software is furnished to do so, subject to | ||
the following conditions: | ||
The above copyright notice and this permission notice shall be | ||
included in all copies or substantial portions of the Software. | ||
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | ||
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | ||
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | ||
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE | ||
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION | ||
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION | ||
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ | ||
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#include "compiler.h" | ||
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#include <libunwind.h> | ||
#include <stdio.h> | ||
#include <stdlib.h> | ||
#include <string.h> | ||
#include <unistd.h> | ||
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#include <sys/resource.h> | ||
#include <sys/mman.h> | ||
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#define panic(args...) \ | ||
{ fprintf (stderr, args); exit (-1); } | ||
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void * stack_start; | ||
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#define PAGE_SIZE 4096 | ||
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void do_backtrace (void) | ||
{ | ||
void* buffer[1024]; | ||
int size = 1024; | ||
mprotect((void*)((uintptr_t)stack_start & ~(PAGE_SIZE - 1)), | ||
PAGE_SIZE, PROT_NONE); | ||
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unw_cursor_t cursor; | ||
unw_word_t ip, sp; | ||
unw_context_t uc; | ||
int ret; | ||
int steps = 0; | ||
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unw_getcontext (&uc); | ||
if (unw_init_local (&cursor, &uc) < 0) | ||
panic ("unw_init_local failed!\n"); | ||
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do | ||
{ | ||
unw_get_reg (&cursor, UNW_REG_IP, &ip); | ||
unw_get_reg (&cursor, UNW_REG_SP, &sp); | ||
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ret = unw_step (&cursor); | ||
if (ret < 0) | ||
{ | ||
unw_get_reg (&cursor, UNW_REG_IP, &ip); | ||
} | ||
steps ++; | ||
} | ||
while (ret > 0); | ||
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if (steps < 5) | ||
{ | ||
exit(-1); | ||
} | ||
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mprotect((void*)((uintptr_t)stack_start & ~(PAGE_SIZE - 1)), | ||
PAGE_SIZE, PROT_READ|PROT_WRITE); | ||
} | ||
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void consume_and_run (int depth) | ||
{ | ||
unw_cursor_t cursor; | ||
unw_context_t uc; | ||
char string[1024]; | ||
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sprintf (string, "hello %p %p\n", &cursor, &uc); | ||
if (depth == 0) { | ||
do_backtrace(); | ||
} else { | ||
consume_and_run(depth - 1); | ||
} | ||
} | ||
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int | ||
main (int argc, char **argv UNUSED) | ||
{ | ||
int start; | ||
unw_context_t uc; | ||
unw_cursor_t cursor; | ||
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stack_start = &start; | ||
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// Initialize pipe mem validate check, opens file descriptors | ||
unw_getcontext(&uc); | ||
if (unw_init_local (&cursor, &uc) < 0) | ||
panic ("unw_init_local failed!\n"); | ||
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int i; | ||
for (i = 3; i < 10; i++) | ||
{ | ||
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pid_t childpid = fork(); | ||
if (!childpid) | ||
{ | ||
/* Close fds and make sure we still work */ | ||
int ret = close(i); | ||
} | ||
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int status; | ||
if (childpid) | ||
{ | ||
wait(&status); | ||
if (WIFEXITED(status)) | ||
return WEXITSTATUS(status); | ||
else | ||
return -1; | ||
} | ||
else | ||
{ | ||
consume_and_run (10); | ||
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return 0; | ||
} | ||
} | ||
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return 0; | ||
} |
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