diff options
Diffstat (limited to 'drivers/misc/lkdtm_bugs.c')
| -rw-r--r-- | drivers/misc/lkdtm_bugs.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c index 182ae1894b32..f336206d4b1f 100644 --- a/drivers/misc/lkdtm_bugs.c +++ b/drivers/misc/lkdtm_bugs.c @@ -5,8 +5,13 @@ * test source files. */ #include "lkdtm.h" +#include <linux/list.h> #include <linux/sched.h> +struct lkdtm_list { + struct list_head node; +}; + /* * Make sure our attempts to over run the kernel stack doesn't trigger * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we @@ -146,3 +151,66 @@ void lkdtm_ATOMIC_OVERFLOW(void) pr_info("attempting bad atomic overflow\n"); atomic_inc(&over); } + +void lkdtm_CORRUPT_LIST_ADD(void) +{ + /* + * Initially, an empty list via LIST_HEAD: + * test_head.next = &test_head + * test_head.prev = &test_head + */ + LIST_HEAD(test_head); + struct lkdtm_list good, bad; + void *target[2] = { }; + void *redirection = ⌖ + + pr_info("attempting good list addition\n"); + + /* + * Adding to the list performs these actions: + * test_head.next->prev = &good.node + * good.node.next = test_head.next + * good.node.prev = test_head + * test_head.next = good.node + */ + list_add(&good.node, &test_head); + + pr_info("attempting corrupted list addition\n"); + /* + * In simulating this "write what where" primitive, the "what" is + * the address of &bad.node, and the "where" is the address held + * by "redirection". + */ + test_head.next = redirection; + list_add(&bad.node, &test_head); + + if (target[0] == NULL && target[1] == NULL) + pr_err("Overwrite did not happen, but no BUG?!\n"); + else + pr_err("list_add() corruption not detected!\n"); +} + +void lkdtm_CORRUPT_LIST_DEL(void) +{ + LIST_HEAD(test_head); + struct lkdtm_list item; + void *target[2] = { }; + void *redirection = ⌖ + + list_add(&item.node, &test_head); + + pr_info("attempting good list removal\n"); + list_del(&item.node); + + pr_info("attempting corrupted list removal\n"); + list_add(&item.node, &test_head); + + /* As with the list_add() test above, this corrupts "next". */ + item.node.next = redirection; + list_del(&item.node); + + if (target[0] == NULL && target[1] == NULL) + pr_err("Overwrite did not happen, but no BUG?!\n"); + else + pr_err("list_del() corruption not detected!\n"); +} |