diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile index fb10eafe9bde..c70b3822013f 100644 --- a/drivers/misc/lkdtm/Makefile +++ b/drivers/misc/lkdtm/Makefile @@ -9,6 +9,7 @@ lkdtm-$(CONFIG_LKDTM) += refcount.o lkdtm-$(CONFIG_LKDTM) += rodata_objcopy.o lkdtm-$(CONFIG_LKDTM) += usercopy.o lkdtm-$(CONFIG_LKDTM) += stackleak.o +lkdtm-$(CONFIG_LKDTM) += cfi.o KASAN_SANITIZE_stackleak.o := n KCOV_INSTRUMENT_rodata.o := n diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 1606658b9b7e..98fad7909592 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -75,7 +75,12 @@ static int warn_counter; void lkdtm_WARNING(void) { - WARN(1, "Warning message trigger count: %d\n", warn_counter++); + WARN_ON(++warn_counter); +} + +void lkdtm_WARNING_MESSAGE(void) +{ + WARN(1, "Warning message trigger count: %d\n", ++warn_counter); } void lkdtm_EXCEPTION(void) diff --git a/drivers/misc/lkdtm/cfi.c b/drivers/misc/lkdtm/cfi.c new file mode 100644 index 000000000000..e73ebdbfa806 --- /dev/null +++ b/drivers/misc/lkdtm/cfi.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This is for all the tests relating directly to Control Flow Integrity. + */ +#include "lkdtm.h" + +static int called_count; + +/* Function taking one argument, without a return value. */ +static noinline void lkdtm_increment_void(int *counter) +{ + (*counter)++; +} + +/* Function taking one argument, returning int. */ +static noinline int lkdtm_increment_int(int *counter) +{ + (*counter)++; + + return *counter; +} +/* + * This tries to call an indirect function with a mismatched prototype. + */ +void lkdtm_CFI_FORWARD_PROTO(void) +{ + /* + * Matches lkdtm_increment_void()'s prototype, but not + * lkdtm_increment_int()'s prototype. + */ + void (*func)(int *); + + pr_info("Calling matched prototype ...\n"); + func = lkdtm_increment_void; + func(&called_count); + + pr_info("Calling mismatched prototype ...\n"); + func = (void *)lkdtm_increment_int; + func(&called_count); + + pr_info("Fail: survived mismatched prototype function call!\n"); +} diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index 66ae6b2a6950..cbc4c9045a99 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -104,6 +104,7 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(PANIC), CRASHTYPE(BUG), CRASHTYPE(WARNING), + CRASHTYPE(WARNING_MESSAGE), CRASHTYPE(EXCEPTION), CRASHTYPE(LOOP), CRASHTYPE(EXHAUST_STACK), @@ -169,6 +170,7 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(USERCOPY_KERNEL), CRASHTYPE(USERCOPY_KERNEL_DS), CRASHTYPE(STACKLEAK_ERASING), + CRASHTYPE(CFI_FORWARD_PROTO), }; diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 6a284a87a037..ab446e0bde97 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -11,6 +11,7 @@ void __init lkdtm_bugs_init(int *recur_param); void lkdtm_PANIC(void); void lkdtm_BUG(void); void lkdtm_WARNING(void); +void lkdtm_WARNING_MESSAGE(void); void lkdtm_EXCEPTION(void); void lkdtm_LOOP(void); void lkdtm_EXHAUST_STACK(void); @@ -95,4 +96,7 @@ void lkdtm_USERCOPY_KERNEL_DS(void); /* lkdtm_stackleak.c */ void lkdtm_STACKLEAK_ERASING(void); +/* cfi.c */ +void lkdtm_CFI_FORWARD_PROTO(void); + #endif