From 58ff537109ac863d4ec83baf8413b17dcc10101c Mon Sep 17 00:00:00 2001 From: Samuel Holland Date: Wed, 31 Jul 2024 20:36:59 -0700 Subject: [PATCH 1/2] riscv: Omit optimized string routines when using KASAN The optimized string routines are implemented in assembly, so they are not instrumented for use with KASAN. Fall back to the C version of the routines in order to improve KASAN coverage. This fixes the kasan_strings() unit test. Signed-off-by: Samuel Holland Reviewed-by: Alexandre Ghiti Tested-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20240801033725.28816-2-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/string.h | 2 ++ arch/riscv/kernel/riscv_ksyms.c | 3 --- arch/riscv/lib/Makefile | 2 ++ arch/riscv/lib/strcmp.S | 1 + arch/riscv/lib/strlen.S | 1 + arch/riscv/lib/strncmp.S | 1 + arch/riscv/purgatory/Makefile | 2 ++ 7 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h index a96b1fea24fe..5ba77f60bf0b 100644 --- a/arch/riscv/include/asm/string.h +++ b/arch/riscv/include/asm/string.h @@ -19,6 +19,7 @@ extern asmlinkage void *__memcpy(void *, const void *, size_t); extern asmlinkage void *memmove(void *, const void *, size_t); extern asmlinkage void *__memmove(void *, const void *, size_t); +#if !(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) #define __HAVE_ARCH_STRCMP extern asmlinkage int strcmp(const char *cs, const char *ct); @@ -27,6 +28,7 @@ extern asmlinkage __kernel_size_t strlen(const char *); #define __HAVE_ARCH_STRNCMP extern asmlinkage int strncmp(const char *cs, const char *ct, size_t count); +#endif /* For those files which don't want to check by kasan. */ #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c index a72879b4249a..5ab1c7e1a6ed 100644 --- a/arch/riscv/kernel/riscv_ksyms.c +++ b/arch/riscv/kernel/riscv_ksyms.c @@ -12,9 +12,6 @@ EXPORT_SYMBOL(memset); EXPORT_SYMBOL(memcpy); EXPORT_SYMBOL(memmove); -EXPORT_SYMBOL(strcmp); -EXPORT_SYMBOL(strlen); -EXPORT_SYMBOL(strncmp); EXPORT_SYMBOL(__memset); EXPORT_SYMBOL(__memcpy); EXPORT_SYMBOL(__memmove); diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index 2b369f51b0a5..8eec6b69a875 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -3,9 +3,11 @@ lib-y += delay.o lib-y += memcpy.o lib-y += memset.o lib-y += memmove.o +ifeq ($(CONFIG_KASAN_GENERIC)$(CONFIG_KASAN_SW_TAGS),) lib-y += strcmp.o lib-y += strlen.o lib-y += strncmp.o +endif lib-y += csum.o ifeq ($(CONFIG_MMU), y) lib-$(CONFIG_RISCV_ISA_V) += uaccess_vector.o diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S index 687b2bea5c43..542301a67a2f 100644 --- a/arch/riscv/lib/strcmp.S +++ b/arch/riscv/lib/strcmp.S @@ -120,3 +120,4 @@ strcmp_zbb: .option pop #endif SYM_FUNC_END(strcmp) +EXPORT_SYMBOL(strcmp) diff --git a/arch/riscv/lib/strlen.S b/arch/riscv/lib/strlen.S index 8ae3064e45ff..962983b73251 100644 --- a/arch/riscv/lib/strlen.S +++ b/arch/riscv/lib/strlen.S @@ -131,3 +131,4 @@ strlen_zbb: #endif SYM_FUNC_END(strlen) SYM_FUNC_ALIAS(__pi_strlen, strlen) +EXPORT_SYMBOL(strlen) diff --git a/arch/riscv/lib/strncmp.S b/arch/riscv/lib/strncmp.S index aba5b3148621..0f359ea2f55b 100644 --- a/arch/riscv/lib/strncmp.S +++ b/arch/riscv/lib/strncmp.S @@ -136,3 +136,4 @@ strncmp_zbb: .option pop #endif SYM_FUNC_END(strncmp) +EXPORT_SYMBOL(strncmp) diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile index f11945ee2490..fb9c917c9b45 100644 --- a/arch/riscv/purgatory/Makefile +++ b/arch/riscv/purgatory/Makefile @@ -1,7 +1,9 @@ # SPDX-License-Identifier: GPL-2.0 purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memcpy.o memset.o +ifeq ($(CONFIG_KASAN_GENERIC)$(CONFIG_KASAN_SW_TAGS),) purgatory-y += strcmp.o strlen.o strncmp.o +endif targets += $(purgatory-y) PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y)) From 77514915b72c51ebc1c30a67a54d4a90ca2a4a39 Mon Sep 17 00:00:00 2001 From: Samuel Holland Date: Wed, 31 Jul 2024 20:37:00 -0700 Subject: [PATCH 2/2] riscv: Enable bitops instrumentation Instead of implementing the bitops functions directly in assembly, provide the arch_-prefixed versions and use the wrappers from asm-generic to add instrumentation. This improves KASAN coverage and fixes the kasan_bitops_generic() unit test. Signed-off-by: Samuel Holland Reviewed-by: Alexandre Ghiti Tested-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20240801033725.28816-3-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/bitops.h | 43 ++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 20 deletions(-) diff --git a/arch/riscv/include/asm/bitops.h b/arch/riscv/include/asm/bitops.h index 71af9ecfcfcb..fae152ea0508 100644 --- a/arch/riscv/include/asm/bitops.h +++ b/arch/riscv/include/asm/bitops.h @@ -222,44 +222,44 @@ static __always_inline int variable_fls(unsigned int x) #define __NOT(x) (~(x)) /** - * test_and_set_bit - Set a bit and return its old value + * arch_test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from * * This operation may be reordered on other architectures than x86. */ -static inline int test_and_set_bit(int nr, volatile unsigned long *addr) +static inline int arch_test_and_set_bit(int nr, volatile unsigned long *addr) { return __test_and_op_bit(or, __NOP, nr, addr); } /** - * test_and_clear_bit - Clear a bit and return its old value + * arch_test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from * * This operation can be reordered on other architectures other than x86. */ -static inline int test_and_clear_bit(int nr, volatile unsigned long *addr) +static inline int arch_test_and_clear_bit(int nr, volatile unsigned long *addr) { return __test_and_op_bit(and, __NOT, nr, addr); } /** - * test_and_change_bit - Change a bit and return its old value + * arch_test_and_change_bit - Change a bit and return its old value * @nr: Bit to change * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ -static inline int test_and_change_bit(int nr, volatile unsigned long *addr) +static inline int arch_test_and_change_bit(int nr, volatile unsigned long *addr) { return __test_and_op_bit(xor, __NOP, nr, addr); } /** - * set_bit - Atomically set a bit in memory + * arch_set_bit - Atomically set a bit in memory * @nr: the bit to set * @addr: the address to start counting from * @@ -270,13 +270,13 @@ static inline int test_and_change_bit(int nr, volatile unsigned long *addr) * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ -static inline void set_bit(int nr, volatile unsigned long *addr) +static inline void arch_set_bit(int nr, volatile unsigned long *addr) { __op_bit(or, __NOP, nr, addr); } /** - * clear_bit - Clears a bit in memory + * arch_clear_bit - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from * @@ -284,13 +284,13 @@ static inline void set_bit(int nr, volatile unsigned long *addr) * on non x86 architectures, so if you are writing portable code, * make sure not to rely on its reordering guarantees. */ -static inline void clear_bit(int nr, volatile unsigned long *addr) +static inline void arch_clear_bit(int nr, volatile unsigned long *addr) { __op_bit(and, __NOT, nr, addr); } /** - * change_bit - Toggle a bit in memory + * arch_change_bit - Toggle a bit in memory * @nr: Bit to change * @addr: Address to start counting from * @@ -298,40 +298,40 @@ static inline void clear_bit(int nr, volatile unsigned long *addr) * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ -static inline void change_bit(int nr, volatile unsigned long *addr) +static inline void arch_change_bit(int nr, volatile unsigned long *addr) { __op_bit(xor, __NOP, nr, addr); } /** - * test_and_set_bit_lock - Set a bit and return its old value, for lock + * arch_test_and_set_bit_lock - Set a bit and return its old value, for lock * @nr: Bit to set * @addr: Address to count from * * This operation is atomic and provides acquire barrier semantics. * It can be used to implement bit locks. */ -static inline int test_and_set_bit_lock( +static inline int arch_test_and_set_bit_lock( unsigned long nr, volatile unsigned long *addr) { return __test_and_op_bit_ord(or, __NOP, nr, addr, .aq); } /** - * clear_bit_unlock - Clear a bit in memory, for unlock + * arch_clear_bit_unlock - Clear a bit in memory, for unlock * @nr: the bit to set * @addr: the address to start counting from * * This operation is atomic and provides release barrier semantics. */ -static inline void clear_bit_unlock( +static inline void arch_clear_bit_unlock( unsigned long nr, volatile unsigned long *addr) { __op_bit_ord(and, __NOT, nr, addr, .rl); } /** - * __clear_bit_unlock - Clear a bit in memory, for unlock + * arch___clear_bit_unlock - Clear a bit in memory, for unlock * @nr: the bit to set * @addr: the address to start counting from * @@ -345,13 +345,13 @@ static inline void clear_bit_unlock( * non-atomic property here: it's a lot more instructions and we still have to * provide release semantics anyway. */ -static inline void __clear_bit_unlock( +static inline void arch___clear_bit_unlock( unsigned long nr, volatile unsigned long *addr) { - clear_bit_unlock(nr, addr); + arch_clear_bit_unlock(nr, addr); } -static inline bool xor_unlock_is_negative_byte(unsigned long mask, +static inline bool arch_xor_unlock_is_negative_byte(unsigned long mask, volatile unsigned long *addr) { unsigned long res; @@ -369,6 +369,9 @@ static inline bool xor_unlock_is_negative_byte(unsigned long mask, #undef __NOT #undef __AMO +#include +#include + #include #include #include