diff options
| author | Jann Horn <[email protected]> | 2018-08-28 22:14:21 +0200 |
|---|---|---|
| committer | Thomas Gleixner <[email protected]> | 2018-09-03 15:12:10 +0200 |
| commit | bef459026b161fbc39d20dcba698ed0cfffbac38 (patch) | |
| tree | da222ce16f935127b188f773d843a95f1f9dca4a | |
| parent | 9da3f2b74054406f87dff7101a569217ffceb29b (diff) | |
lkdtm: Test copy_to_user() on bad kernel pointer under KERNEL_DS
Test whether the kernel WARN()s when, under KERNEL_DS, a bad kernel pointer
is used as "userspace" pointer. Should normally be used in "DIRECT" mode.
Signed-off-by: Jann Horn <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Kees Cook <[email protected]>
Acked-by: Kees Cook <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Masami Hiramatsu <[email protected]>
Cc: "Naveen N. Rao" <[email protected]>
Cc: Anil S Keshavamurthy <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: [email protected]
Cc: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
| -rw-r--r-- | drivers/misc/lkdtm/core.c | 1 | ||||
| -rw-r--r-- | drivers/misc/lkdtm/lkdtm.h | 1 | ||||
| -rw-r--r-- | drivers/misc/lkdtm/usercopy.c | 13 |
3 files changed, 15 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index 2154d1bfd18b..5a755590d3dc 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -183,6 +183,7 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(USERCOPY_STACK_FRAME_FROM), CRASHTYPE(USERCOPY_STACK_BEYOND), CRASHTYPE(USERCOPY_KERNEL), + CRASHTYPE(USERCOPY_KERNEL_DS), }; diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 9e513dcfd809..07db641d71d0 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -82,5 +82,6 @@ void lkdtm_USERCOPY_STACK_FRAME_TO(void); void lkdtm_USERCOPY_STACK_FRAME_FROM(void); void lkdtm_USERCOPY_STACK_BEYOND(void); void lkdtm_USERCOPY_KERNEL(void); +void lkdtm_USERCOPY_KERNEL_DS(void); #endif diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c index 9725aed305bb..389475b25bb7 100644 --- a/drivers/misc/lkdtm/usercopy.c +++ b/drivers/misc/lkdtm/usercopy.c @@ -322,6 +322,19 @@ free_user: vm_munmap(user_addr, PAGE_SIZE); } +void lkdtm_USERCOPY_KERNEL_DS(void) +{ + char __user *user_ptr = (char __user *)ERR_PTR(-EINVAL); + mm_segment_t old_fs = get_fs(); + char buf[10] = {0}; + + pr_info("attempting copy_to_user on unmapped kernel address\n"); + set_fs(KERNEL_DS); + if (copy_to_user(user_ptr, buf, sizeof(buf))) + pr_info("copy_to_user un unmapped kernel address failed\n"); + set_fs(old_fs); +} + void __init lkdtm_usercopy_init(void) { /* Prepare cache that lacks SLAB_USERCOPY flag. */ |