diff options
| author | Kees Cook <keescook@chromium.org> | 2017-08-04 13:04:21 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2017-08-04 13:04:21 -0700 |
| commit | 7b25a85c9d9f796c5be7ad3fb8b9553d3e2ed958 (patch) | |
| tree | 8917e901a8728c16f8e848227fbd6e3601019830 /drivers/misc | |
| parent | c7fea48876773603721f545f8c1a2f894291ef85 (diff) | |
lkdtm: Test VMAP_STACK allocates leading/trailing guard pages
Two new tests STACK_GUARD_PAGE_LEADING and STACK_GUARD_PAGE_TRAILING
attempt to read the byte before and after, respectively, of the current
stack frame, which should fault.
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'drivers/misc')
| -rw-r--r-- | drivers/misc/lkdtm.h | 2 | ||||
| -rw-r--r-- | drivers/misc/lkdtm_bugs.c | 30 | ||||
| -rw-r--r-- | drivers/misc/lkdtm_core.c | 2 |
3 files changed, 34 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h index 063f5d651076..3c8627ca5f42 100644 --- a/drivers/misc/lkdtm.h +++ b/drivers/misc/lkdtm.h @@ -22,6 +22,8 @@ void lkdtm_HUNG_TASK(void); void lkdtm_CORRUPT_LIST_ADD(void); void lkdtm_CORRUPT_LIST_DEL(void); void lkdtm_CORRUPT_USER_DS(void); +void lkdtm_STACK_GUARD_PAGE_LEADING(void); +void lkdtm_STACK_GUARD_PAGE_TRAILING(void); /* lkdtm_heap.c */ void lkdtm_OVERWRITE_ALLOCATION(void); diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c index ef3d06f901fc..041fe6e9532a 100644 --- a/drivers/misc/lkdtm_bugs.c +++ b/drivers/misc/lkdtm_bugs.c @@ -8,6 +8,7 @@ #include <linux/list.h> #include <linux/sched.h> #include <linux/sched/signal.h> +#include <linux/sched/task_stack.h> #include <linux/uaccess.h> struct lkdtm_list { @@ -199,6 +200,7 @@ void lkdtm_CORRUPT_LIST_DEL(void) pr_err("list_del() corruption not detected!\n"); } +/* Test if unbalanced set_fs(KERNEL_DS)/set_fs(USER_DS) check exists. */ void lkdtm_CORRUPT_USER_DS(void) { pr_info("setting bad task size limit\n"); @@ -207,3 +209,31 @@ void lkdtm_CORRUPT_USER_DS(void) /* Make sure we do not keep running with a KERNEL_DS! */ force_sig(SIGKILL, current); } + +/* Test that VMAP_STACK is actually allocating with a leading guard page */ +void lkdtm_STACK_GUARD_PAGE_LEADING(void) +{ + const unsigned char *stack = task_stack_page(current); + const unsigned char *ptr = stack - 1; + volatile unsigned char byte; + + pr_info("attempting bad read from page below current stack\n"); + + byte = *ptr; + + pr_err("FAIL: accessed page before stack!\n"); +} + +/* Test that VMAP_STACK is actually allocating with a trailing guard page */ +void lkdtm_STACK_GUARD_PAGE_TRAILING(void) +{ + const unsigned char *stack = task_stack_page(current); + const unsigned char *ptr = stack + THREAD_SIZE; + volatile unsigned char byte; + + pr_info("attempting bad read from page above current stack\n"); + + byte = *ptr; + + pr_err("FAIL: accessed page after stack!\n"); +} diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c index 51decc07eeda..9e98d7ef5503 100644 --- a/drivers/misc/lkdtm_core.c +++ b/drivers/misc/lkdtm_core.c @@ -201,6 +201,8 @@ struct crashtype crashtypes[] = { CRASHTYPE(CORRUPT_LIST_DEL), CRASHTYPE(CORRUPT_USER_DS), CRASHTYPE(CORRUPT_STACK), + CRASHTYPE(STACK_GUARD_PAGE_LEADING), + CRASHTYPE(STACK_GUARD_PAGE_TRAILING), CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE), CRASHTYPE(OVERWRITE_ALLOCATION), CRASHTYPE(WRITE_AFTER_FREE), |