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[x86-64] Make a best effort at validating pointers before dereferencing them.

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Signed-off-by: Arun Sharma <arun.sharma@google.com>
This commit is contained in:
Arun Sharma 2006-07-26 21:46:39 -06:00 committed by David Mosberger-Tang
parent 4312719cbc
commit 527225e492
1 changed files with 7 additions and 0 deletions
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7
src/x86_64/Ginit.c
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@ -27,6 +27,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
#include <sys/mman.h>
#include "unwind_i.h" #include "unwind_i.h"
@ -103,6 +104,9 @@ get_dyn_info_list_addr (unw_addr_space_t as, unw_word_t *dyn_info_list_addr,
return 0; return 0;
} }
#define PAGE_SIZE 4096
#define PAGE_START(a) ((a) & ~(PAGE_SIZE-1))
static int static int
access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write, access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write,
void *arg) void *arg)
@ -114,6 +118,9 @@ access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write,
} }
else else
{ {
/* validate address */
if (msync(PAGE_START(addr), 1, MS_SYNC) == -1)
return -1;
*val = *(unw_word_t *) addr; *val = *(unw_word_t *) addr;
Debug (16, "mem[%016lx] -> %lx\n", addr, *val); Debug (16, "mem[%016lx] -> %lx\n", addr, *val);
} }