[igt-dev] [i-g-t, v2] igt/gem_mmap_offset: Adding subtest oob_read

[Kamil Konieczny]

Dnia 2022-03-11 at 12:33:09 +0530, Mastan Katragadda napisał(a):
> This test will Detect A missing bounds check in vm_access().
---------------- ^
> can lead to an out-of-bounds read or write in the adjacent memory area.
> 

Commit description looks like copy-paste, mixed. Maybe just
s/This test will Detect A/Detect a/

and remove dot after "vm_access()."

> Changes Since V1:
> 	- Incorporated minor changes as suggested in feedback [Chris/Matthew].
>         - Fixed build failures.
> 
> Signed-off-by: Mastan Katragadda <mastanx.katragadda at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Matthew Auld <matthew.auld at intel.com>
> ---
>  tests/i915/gem_mmap_offset.c | 44 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
> 
> diff --git a/tests/i915/gem_mmap_offset.c b/tests/i915/gem_mmap_offset.c
> index 8148f0a2..c8fab18b 100644
> --- a/tests/i915/gem_mmap_offset.c
> +++ b/tests/i915/gem_mmap_offset.c
> @@ -22,6 +22,8 @@
>   */
>  
>  #include <errno.h>
> +#include <unistd.h>
> +#include <fcntl.h>
>  #include <pthread.h>
>  #include <signal.h>
>  #include <stdatomic.h>
> @@ -289,6 +291,44 @@ static void *memchr_inv(const void *s, int c, size_t n)
>  	return NULL;
>  }
>  
> +static void
> +test_oob_read(int i915)
> +{
> +	unsigned char read_buf[4096];
> +	uint32_t handle;
> +	uintptr_t addr;
> +	int memfd;
> +	int ret;
> +
> +	handle = gem_create(i915, 4096);

What if page size is bigger ? You ask for only 4096 bytes, but
you can get more depending on page size.

Regards,
Kamil Konieczny

> +
> +	for_each_mmap_offset_type(i915, t) {
> +		uint32_t *ptr;
> +
> +		ptr = __mmap_offset(i915, handle, 0, 4096,
> +				    PROT_READ | PROT_WRITE,
> +				    t->type);
> +		if (!ptr)
> +			continue;
> +
> +		memfd = open("/proc/self/mem", O_RDWR);
> +		igt_require_f(memfd != -1, "/proc/self/mem\n");
> +
> +		addr = (uintptr_t)ptr + 4092;
> +		ret = lseek(memfd, addr, SEEK_SET);
> +		igt_assert_f(ret != -1, "lseek failed\n");
> +
> +		/* Triggering the buf (out of bound read) */
> +		ret = read(memfd, read_buf, 8);
> +		igt_assert(ret == -1 && errno ==  EIO);
> +
> +		munmap(ptr, 4096);
> +		close(memfd);
> +	}
> +
> +	gem_close(i915, handle);
> +}
> +
>  static void test_ptrace(int i915)
>  {
>  	const unsigned int SZ = 3 * 4096;
> @@ -692,6 +732,10 @@ igt_main
>  	igt_subtest_f("pf-nonblock")
>  		pf_nonblock(i915);
>  
> +	igt_describe("Check Linear Out-Of-Bound in Vm_access");
> +	igt_subtest("oob-read")
> +		test_oob_read(i915);
> +
>  	igt_subtest_with_dynamic("ptrace")
>  		test_ptrace(i915);
>  
> -- 
> 2.25.1
>