@@ -1 +1,2 @@
+exec_target
pac
@@ -12,7 +12,7 @@ pauth_cc_support := $(shell if ($(CC) $(CFLAGS) -march=armv8.3-a -E -x c /dev/nu
ifeq ($(pauth_cc_support),1)
TEST_GEN_PROGS := pac
-TEST_GEN_FILES := pac_corruptor.o
+TEST_GEN_FILES := pac_corruptor.o helper.o
endif
include ../../lib.mk
@@ -23,10 +23,13 @@ ifeq ($(pauth_cc_support),1)
$(OUTPUT)/pac_corruptor.o: pac_corruptor.S
$(CC) -c $^ -o $@ $(CFLAGS) -march=armv8.3-a
+$(OUTPUT)/helper.o: helper.c
+ $(CC) -c $^ -o $@ $(CFLAGS) -march=armv8.3-a
+
# when -mbranch-protection is enabled and the target architecture is ARMv8.3 or
# greater, gcc emits pac* instructions which are not in HINT NOP space,
# preventing the tests from occurring at all. Compile for ARMv8.2 so tests can
# run on earlier targets and print a meaningful error messages
-$(OUTPUT)/pac: pac.c $(OUTPUT)/pac_corruptor.o
+$(OUTPUT)/pac: pac.c $(OUTPUT)/pac_corruptor.o $(OUTPUT)/helper.o
$(CC) $^ -o $@ $(CFLAGS) -march=armv8.2-a
endif
new file mode 100644
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020 ARM Limited
+
+#include "helper.h"
+
+size_t keyia_sign(size_t ptr)
+{
+ asm volatile("paciza %0" : "+r" (ptr));
+ return ptr;
+}
+
+size_t keyib_sign(size_t ptr)
+{
+ asm volatile("pacizb %0" : "+r" (ptr));
+ return ptr;
+}
+
+size_t keyda_sign(size_t ptr)
+{
+ asm volatile("pacdza %0" : "+r" (ptr));
+ return ptr;
+}
+
+size_t keydb_sign(size_t ptr)
+{
+ asm volatile("pacdzb %0" : "+r" (ptr));
+ return ptr;
+}
+
+size_t keyg_sign(size_t ptr)
+{
+ /* output is encoded in the upper 32 bits */
+ size_t dest = 0;
+ size_t modifier = 0;
+
+ asm volatile("pacga %0, %1, %2" : "=r" (dest) : "r" (ptr), "r" (modifier));
+
+ return dest;
+}
@@ -4,6 +4,15 @@
#ifndef _HELPER_H_
#define _HELPER_H_
+#include <stdlib.h>
+
void pac_corruptor(void);
+/* PAuth sign a value with key ia and modifier value 0 */
+size_t keyia_sign(size_t val);
+size_t keyib_sign(size_t val);
+size_t keyda_sign(size_t val);
+size_t keydb_sign(size_t val);
+size_t keyg_sign(size_t val);
+
#endif
@@ -8,12 +8,25 @@
#include "../../kselftest_harness.h"
#include "helper.h"
+#define PAC_COLLISION_ATTEMPTS 10
+/*
+ * The kernel sets TBID by default. So bits 55 and above should remain
+ * untouched no matter what.
+ * The VA space size is 48 bits. Bigger is opt-in.
+ */
+#define PAC_MASK (~0xff80ffffffffffff)
#define ASSERT_PAUTH_ENABLED() \
do { \
unsigned long hwcaps = getauxval(AT_HWCAP); \
/* data key instructions are not in NOP space. This prevents a SIGILL */ \
ASSERT_NE(0, hwcaps & HWCAP_PACA) TH_LOG("PAUTH not enabled"); \
} while (0)
+#define ASSERT_GENERIC_PAUTH_ENABLED() \
+do { \
+ unsigned long hwcaps = getauxval(AT_HWCAP); \
+ /* generic key instructions are not in NOP space. This prevents a SIGILL */ \
+ ASSERT_NE(0, hwcaps & HWCAP_PACG) TH_LOG("Generic PAUTH not enabled"); \
+} while (0)
sigjmp_buf jmpbuf;
void pac_signal_handler(int signum, siginfo_t *si, void *uc)
@@ -41,4 +54,42 @@ TEST(corrupt_pac)
}
}
+/*
+ * There are no separate pac* and aut* controls so checking only the pac*
+ * instructions is sufficient
+ */
+TEST(pac_instructions_not_nop)
+{
+ size_t keyia = 0;
+ size_t keyib = 0;
+ size_t keyda = 0;
+ size_t keydb = 0;
+
+ ASSERT_PAUTH_ENABLED();
+
+ for (int i = 0; i < PAC_COLLISION_ATTEMPTS; i++) {
+ keyia |= keyia_sign(i) & PAC_MASK;
+ keyib |= keyib_sign(i) & PAC_MASK;
+ keyda |= keyda_sign(i) & PAC_MASK;
+ keydb |= keydb_sign(i) & PAC_MASK;
+ }
+
+ ASSERT_NE(0, keyia) TH_LOG("keyia instructions did nothing");
+ ASSERT_NE(0, keyib) TH_LOG("keyib instructions did nothing");
+ ASSERT_NE(0, keyda) TH_LOG("keyda instructions did nothing");
+ ASSERT_NE(0, keydb) TH_LOG("keydb instructions did nothing");
+}
+
+TEST(pac_instructions_not_nop_generic)
+{
+ size_t keyg = 0;
+
+ ASSERT_GENERIC_PAUTH_ENABLED();
+
+ for (int i = 0; i < PAC_COLLISION_ATTEMPTS; i++)
+ keyg |= keyg_sign(i) & PAC_MASK;
+
+ ASSERT_NE(0, keyg) TH_LOG("keyg instructions did nothing");
+}
+
TEST_HARNESS_MAIN