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-rw-r--r--drivers/misc/lkdtm/Makefile1
-rw-r--r--drivers/misc/lkdtm/bugs.c7
-rw-r--r--drivers/misc/lkdtm/cfi.c42
-rw-r--r--drivers/misc/lkdtm/core.c2
-rw-r--r--drivers/misc/lkdtm/lkdtm.h4
5 files changed, 55 insertions, 1 deletions
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 24245ccdba72..7284a22b1a09 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