diff options
| -rw-r--r-- | drivers/misc/lkdtm.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c index 2a6eaf1122b4..42a0a99007be 100644 --- a/drivers/misc/lkdtm.c +++ b/drivers/misc/lkdtm.c @@ -47,11 +47,16 @@ #include <linux/vmalloc.h> #include <linux/mman.h> #include <asm/cacheflush.h> +#include <linux/list.h> #ifdef CONFIG_IDE #include <linux/ide.h> #endif +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 @@ -88,6 +93,8 @@ enum ctype { CT_EXCEPTION, CT_LOOP, CT_OVERFLOW, + CT_CORRUPT_LIST_ADD, + CT_CORRUPT_LIST_DEL, CT_CORRUPT_STACK, CT_UNALIGNED_LOAD_STORE_WRITE, CT_OVERWRITE_ALLOCATION, @@ -126,6 +133,8 @@ static char* cp_type[] = { "EXCEPTION", "LOOP", "OVERFLOW", + "CORRUPT_LIST_ADD", + "CORRUPT_LIST_DEL", "CORRUPT_STACK", "UNALIGNED_LOAD_STORE_WRITE", "OVERWRITE_ALLOCATION", @@ -548,6 +557,67 @@ static void lkdtm_do_action(enum ctype which) do_overwritten(); break; } + case CT_CORRUPT_LIST_ADD: { + /* + * 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"); + break; + } + case CT_CORRUPT_LIST_DEL: { + 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"); + break; + } case CT_NONE: default: break; |