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Dump stack if memwipe() check fails

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This commit is contained in:
Martin Willi
2013-05-03 11:41:51 +02:00
parent 0f499f41dc
commit 1657b4ef26
1 changed files with 19 additions and 3 deletions
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src/libstrongswan/library.c
+19 -3
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@@ -150,13 +150,23 @@ static bool equals(char *a, char *b)
return streq(a, b); return streq(a, b);
} }
/**
* Number of words we write and memwipe() in memwipe check
*/
#define MEMWIPE_WIPE_WORDS 16
/**
* Number of words we check stack for memwiped magic
*/
#define MEMWIPE_CHECK_WORDS (MEMWIPE_WIPE_WORDS * 2)
/** /**
* Write magic to memory, and try to clear it with memwipe() * Write magic to memory, and try to clear it with memwipe()
*/ */
__attribute__((noinline)) __attribute__((noinline))
static void do_magic(int magic, int **stack) static void do_magic(int magic, int **stack)
{ {
int buf[32], i; int buf[MEMWIPE_WIPE_WORDS], i;
/* tell caller where callee stack is (but don't point to buf) */ /* tell caller where callee stack is (but don't point to buf) */
*stack = &i; *stack = &i;
@@ -184,11 +194,18 @@ static bool check_memwipe()
{ /* stack grows down */ { /* stack grows down */
stackdir = -1; stackdir = -1;
} }
for (i = 0; i < 128; i++) for (i = 0; i < MEMWIPE_CHECK_WORDS; i++)
{ {
ptr = ptr + stackdir; ptr = ptr + stackdir;
if (*ptr == magic) if (*ptr == magic)
{ {
ptr = &magic + stackdir;
if (stackdir == -1)
{
ptr -= MEMWIPE_CHECK_WORDS;
}
DBG1(DBG_LIB, "memwipe() check failed: stackdir: %d %b",
stackdir, ptr, (u_int)(MEMWIPE_CHECK_WORDS * sizeof(int)));
return FALSE; return FALSE;
} }
} }
@@ -268,7 +285,6 @@ bool library_init(char *settings)
if (!check_memwipe()) if (!check_memwipe())
{ {
DBG1(DBG_LIB, "memwipe() check failed");
return FALSE; return FALSE;
} }