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support: Add <support/next_to_fault.h>

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Based on the implementation in resolv/tst-inet_pton.c.
This commit is contained in:
Florian Weimer
2017-11-13 17:55:12 +01:00
parent eceed67166
commit cae87e64dc
5 changed files with 120 additions and 56 deletions
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67
resolv/tst-inet_pton.c
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@@ -22,57 +22,10 @@
#include <stdio.h>
#include <string.h>
#include <support/check.h>
#include <support/next_to_fault.h>
#include <support/xunistd.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <unistd.h>
/* Memory region created by next_to_fault_allocate. */
struct next_to_fault
{
/* The user data. */
char *buffer;
size_t length;
/* The entire allocated region. */
void *region_start;
size_t region_size;
};
/* Allocate a buffer of SIZE bytes just before a page which is mapped
with PROT_NONE (so that overrunning the buffer will cause a
fault). */
static struct next_to_fault
next_to_fault_allocate (size_t size)
{
long page_size = sysconf (_SC_PAGE_SIZE);
TEST_VERIFY_EXIT (page_size > 0);
struct next_to_fault result;
result.region_size = roundup (size, page_size) + page_size;
TEST_VERIFY_EXIT (size + page_size > size);
TEST_VERIFY_EXIT (result.region_size > size);
result.region_start
= xmmap (NULL, result.region_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1);
/* Unmap the page after the allocation. */
xmprotect (result.region_start + (result.region_size - page_size),
page_size, PROT_NONE);
/* Align the allocation within the region so that it ends just
before the PROT_NONE page. */
result.buffer = result.region_start + result.region_size - page_size - size;
result.length = size;
return result;
}
/* Deallocate the memory region allocated by
next_to_fault_allocate. */
static void
next_to_fault_free (struct next_to_fault *ntf)
{
xmunmap (ntf->region_start, ntf->region_size);
*ntf = (struct next_to_fault) { NULL, };
}
struct test_case
{
/* The input data. */
@@ -139,12 +92,13 @@ run_one_test (const struct test_case *t)
{
size_t test_len = strlen (t->input);
struct next_to_fault ntf_out4 = next_to_fault_allocate (4);
struct next_to_fault ntf_out6 = next_to_fault_allocate (16);
struct support_next_to_fault ntf_out4 = support_next_to_fault_allocate (4);
struct support_next_to_fault ntf_out6 = support_next_to_fault_allocate (16);
/* inet_pton requires NUL termination. */
{
struct next_to_fault ntf_in = next_to_fault_allocate (test_len + 1);
struct support_next_to_fault ntf_in
= support_next_to_fault_allocate (test_len + 1);
memcpy (ntf_in.buffer, t->input, test_len + 1);
memset (ntf_out4.buffer, 0, 4);
check_result ("inet_pton", t, AF_INET, ntf_out4.buffer,
@@ -152,12 +106,13 @@ run_one_test (const struct test_case *t)
memset (ntf_out6.buffer, 0, 16);
check_result ("inet_pton", t, AF_INET6, ntf_out6.buffer,
inet_pton (AF_INET6, ntf_in.buffer, ntf_out6.buffer));
next_to_fault_free (&ntf_in);
support_next_to_fault_free (&ntf_in);
}
/* __inet_pton_length does not require NUL termination. */
{
struct next_to_fault ntf_in = next_to_fault_allocate (test_len);
struct support_next_to_fault ntf_in
= support_next_to_fault_allocate (test_len);
memcpy (ntf_in.buffer, t->input, test_len);
memset (ntf_out4.buffer, 0, 4);
check_result ("__inet_pton_length", t, AF_INET, ntf_out4.buffer,
@@ -167,11 +122,11 @@ run_one_test (const struct test_case *t)
check_result ("__inet_pton_length", t, AF_INET6, ntf_out6.buffer,
__inet_pton_length (AF_INET6, ntf_in.buffer, ntf_in.length,
ntf_out6.buffer));
next_to_fault_free (&ntf_in);
support_next_to_fault_free (&ntf_in);
}
next_to_fault_free (&ntf_out4);
next_to_fault_free (&ntf_out6);
support_next_to_fault_free (&ntf_out4);
support_next_to_fault_free (&ntf_out6);
}
/* The test cases were manually crafted and the set enhanced with