diff options
| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2018-12-14 16:26:20 +0100 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2019-01-09 21:00:31 +0100 |
| commit | 59a12205d3c32aee4c13ca36889fdf7cfed31126 (patch) | |
| tree | f2de1d775529e2e3b4e57edf669356f2cbec6303 /drivers/misc/lkdtm | |
| parent | lkdtm: Print real addresses (diff) | |
| download | linux-59a12205d3c32aee4c13ca36889fdf7cfed31126.tar.xz linux-59a12205d3c32aee4c13ca36889fdf7cfed31126.zip | |
lkdtm: Add tests for NULL pointer dereference
Introduce lkdtm tests for NULL pointer dereference: check access or exec
at NULL address, since these errors tend to be reported differently from
the general fault error text. For example from x86:
pr_alert("BUG: unable to handle kernel %s at %px\n",
address < PAGE_SIZE ? "NULL pointer dereference" : "paging request",
(void *)address);
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'drivers/misc/lkdtm')
| -rw-r--r-- | drivers/misc/lkdtm/core.c | 2 | ||||
| -rw-r--r-- | drivers/misc/lkdtm/lkdtm.h | 2 | ||||
| -rw-r--r-- | drivers/misc/lkdtm/perms.c | 18 |
3 files changed, 22 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index 5d41c2230d2e..c09133ac9803 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -143,7 +143,9 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(EXEC_VMALLOC), CRASHTYPE(EXEC_RODATA), CRASHTYPE(EXEC_USERSPACE), + CRASHTYPE(EXEC_NULL), CRASHTYPE(ACCESS_USERSPACE), + CRASHTYPE(ACCESS_NULL), CRASHTYPE(WRITE_RO), CRASHTYPE(WRITE_RO_AFTER_INIT), CRASHTYPE(WRITE_KERN), diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 3c6fd327e166..b69ee004a3f7 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -45,7 +45,9 @@ void lkdtm_EXEC_KMALLOC(void); void lkdtm_EXEC_VMALLOC(void); void lkdtm_EXEC_RODATA(void); void lkdtm_EXEC_USERSPACE(void); +void lkdtm_EXEC_NULL(void); void lkdtm_ACCESS_USERSPACE(void); +void lkdtm_ACCESS_NULL(void); /* lkdtm_refcount.c */ void lkdtm_REFCOUNT_INC_OVERFLOW(void); diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c index fa54add6375a..62f76d506f04 100644 --- a/drivers/misc/lkdtm/perms.c +++ b/drivers/misc/lkdtm/perms.c @@ -164,6 +164,11 @@ void lkdtm_EXEC_USERSPACE(void) vm_munmap(user_addr, PAGE_SIZE); } +void lkdtm_EXEC_NULL(void) +{ + execute_location(NULL, CODE_AS_IS); +} + void lkdtm_ACCESS_USERSPACE(void) { unsigned long user_addr, tmp = 0; @@ -195,6 +200,19 @@ void lkdtm_ACCESS_USERSPACE(void) vm_munmap(user_addr, PAGE_SIZE); } +void lkdtm_ACCESS_NULL(void) +{ + unsigned long tmp; + unsigned long *ptr = (unsigned long *)NULL; + + pr_info("attempting bad read at %px\n", ptr); + tmp = *ptr; + tmp += 0xc0dec0de; + + pr_info("attempting bad write at %px\n", ptr); + *ptr = tmp; +} + void __init lkdtm_perms_init(void) { /* Make sure we can write to __ro_after_init values during __init */ |