diff options
| author | Kees Cook <keescook@chromium.org> | 2017-03-24 10:51:25 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-08 17:56:02 +0200 |
| commit | e22aa9d781a27a961581c57442911309fb86a48e (patch) | |
| tree | 96f46cc8f24081f40bdbd41c1a4457258cb75e3b | |
| parent | 8ab44b4003381cf4bae7ccdfe81059aa9ce76033 (diff) | |
lkdtm: add bad USER_DS test
This adds CORRUPT_USER_DS to check that the get_fs() test on syscall
return (via __VERIFY_PRE_USERMODE_STATE) still sees USER_DS. Since
trying to deal with values other than USER_DS and KERNEL_DS across all
architectures in a safe way is not sensible, this sets KERNEL_DS, but
since that could be extremely dangerous if the protection is not present,
it also raises SIGKILL for current, so that no matter what, the process
will die. A successful test will be visible with a BUG(), like all the
other LKDTM tests.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/misc/lkdtm.h | 1 | ||||
| -rw-r--r-- | drivers/misc/lkdtm_bugs.c | 11 | ||||
| -rw-r--r-- | drivers/misc/lkdtm_core.c | 1 |
3 files changed, 13 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h index 67d27be60405..3b4976396ec4 100644 --- a/drivers/misc/lkdtm.h +++ b/drivers/misc/lkdtm.h @@ -27,6 +27,7 @@ void lkdtm_REFCOUNT_ZERO_SUB(void); void lkdtm_REFCOUNT_ZERO_ADD(void); void lkdtm_CORRUPT_LIST_ADD(void); void lkdtm_CORRUPT_LIST_DEL(void); +void lkdtm_CORRUPT_USER_DS(void); /* lkdtm_heap.c */ void lkdtm_OVERWRITE_ALLOCATION(void); diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c index e3f4cd8876b5..ed4f4c56c796 100644 --- a/drivers/misc/lkdtm_bugs.c +++ b/drivers/misc/lkdtm_bugs.c @@ -8,6 +8,8 @@ #include <linux/list.h> #include <linux/refcount.h> #include <linux/sched.h> +#include <linux/sched/signal.h> +#include <linux/uaccess.h> struct lkdtm_list { struct list_head node; @@ -279,3 +281,12 @@ void lkdtm_CORRUPT_LIST_DEL(void) else pr_err("list_del() corruption not detected!\n"); } + +void lkdtm_CORRUPT_USER_DS(void) +{ + pr_info("setting bad task size limit\n"); + set_fs(KERNEL_DS); + + /* Make sure we do not keep running with a KERNEL_DS! */ + force_sig(SIGKILL, current); +} diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c index b9a4cd4a9b68..42d2b8e31e6b 100644 --- a/drivers/misc/lkdtm_core.c +++ b/drivers/misc/lkdtm_core.c @@ -199,6 +199,7 @@ struct crashtype crashtypes[] = { CRASHTYPE(OVERFLOW), CRASHTYPE(CORRUPT_LIST_ADD), CRASHTYPE(CORRUPT_LIST_DEL), + CRASHTYPE(CORRUPT_USER_DS), CRASHTYPE(CORRUPT_STACK), CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE), CRASHTYPE(OVERWRITE_ALLOCATION), |