kasan: add kasan_tag_mismatch prototype

PATCH New Arnd Bergmann 2 participants 3 messages May 9, 2023 – May 12, 2023

Subsystems (3)

Memory management arm64 KASAN

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Arnd Bergmann

author

2023-05-09 14:57 UTC #0 lore raw

PATCH 1/2 kasan: add kasan_tag_mismatch prototype

From: Arnd Bergmann <[email protected]>

The kasan sw-tags implementation contains one function that is only called from assembler and has no prototype in a header. This causes a W=1 warning:

mm/kasan/sw_tags.c:171:6: warning: no previous prototype for 'kasan_tag_mismatch' [-Wmissing-prototypes]
171 | void kasan_tag_mismatch(unsigned long addr, unsigned long access_info,

Add a prototype in the local header to get a clean build.

Signed-off-by Arnd Bergmann <[email protected]>

---
 mm/kasan/kasan.h | 3 +++
 1 file changed, 3 insertions(+)

mm/kasan/kasan.h +3 -0

index f5e4f5f2ba20..cd846ca34f44 100644
@@ -646,4 +646,7 @@ void *__hwasan_memset(void *addr, int c, size_t len);
 void *__hwasan_memmove(void *dest, const void *src, size_t len);
 void *__hwasan_memcpy(void *dest, const void *src, size_t len);
 
+void kasan_tag_mismatch(unsigned long addr, unsigned long access_info,
+			unsigned long ret_ip);
+
 #endif /* __MM_KASAN_KASAN_H */

Signature · 1 line

2.35.1

Arnd Bergmann

author

2023-05-09 14:59 UTC #1 lore raw

PATCH v3 2/2 kasan: use internal prototypes matching gcc-13 builtins

From: Arnd Bergmann <[email protected]>

gcc-13 warns about function definitions for builtin interfaces that have a different prototype, e.g.:

In file included from kasan_test.c:31:
kasan.h:574:6: error: conflicting types for built-in function '__asan_register_globals'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
574 | void __asan_register_globals(struct kasan_global *globals, size_t size);
kasan.h:577:6: error: conflicting types for built-in function '__asan_alloca_poison'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
577 | void __asan_alloca_poison(unsigned long addr, size_t size);
kasan.h:580:6: error: conflicting types for built-in function '__asan_load1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
580 | void __asan_load1(unsigned long addr);
kasan.h:581:6: error: conflicting types for built-in function '__asan_store1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
581 | void __asan_store1(unsigned long addr);
kasan.h:643:6: error: conflicting types for built-in function '__hwasan_tag_memory'; expected 'void(void *, unsigned char, long int)' [-Werror=builtin-declaration-mismatch]
643 | void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);

The two problems are:

- Addresses are passes as 'unsigned long' in the kernel, but gcc-13 expects a 'void *'.

- sizes meant to use a signed ssize_t rather than size_t.

Change all the prototypes to match these. Using 'void *' consistently for addresses gets rid of a couple of type casts, so push that down to the leaf functions where possible.

This now passes all randconfig builds on arm, arm64 and x86, but I have not tested it on the other architectures that support kasan, since they tend to fail randconfig builds in other ways. This might fail if any of the 32-bit architectures expect a 'long' instead of 'int' for the size argument.

The __asan_allocas_unpoison() function prototype is somewhat weird, since it uses a pointer for 'stack_top' and an size_t for 'stack_bottom'. This looks like it is meant to be 'addr' and 'size' like the others, but the implementation clearly treats them as 'top' and 'bottom'.

Signed-off-by Arnd Bergmann <[email protected]>

---
v3: rebase to make it apply cleanly
v2: Remove custom size type that turned out to be unnecessary after all

---
 arch/arm64/kernel/traps.c |   2 +-
 arch/arm64/mm/fault.c     |   2 +-
 include/linux/kasan.h     |   2 +-
 mm/kasan/common.c         |   2 +-
 mm/kasan/generic.c        |  72 ++++++++---------
 mm/kasan/kasan.h          | 160 +++++++++++++++++++-------------------
 mm/kasan/report.c         |  17 ++--
 mm/kasan/report_generic.c |  12 +--
 mm/kasan/report_hw_tags.c |   2 +-
 mm/kasan/report_sw_tags.c |   2 +-
 mm/kasan/shadow.c         |  36 ++++-----
 mm/kasan/sw_tags.c        |  20 ++---
 12 files changed, 164 insertions(+), 165 deletions(-)

arch/arm64/kernel/traps.c +1 -1

index 35a95b78b14f..3f5a21e5968e 100644
@@ -1044,7 +1044,7 @@ static int kasan_handler(struct pt_regs *regs, unsigned long esr)
 	bool recover = esr & KASAN_ESR_RECOVER;
 	bool write = esr & KASAN_ESR_WRITE;
 	size_t size = KASAN_ESR_SIZE(esr);
-	u64 addr = regs->regs[0];
+	void *addr = (void *)regs->regs[0];
 	u64 pc = regs->pc;
 
 	kasan_report(addr, size, write, pc);

arch/arm64/mm/fault.c +1 -1

index f4418382be98..940391ec5e1e 100644
@@ -317,7 +317,7 @@ static void report_tag_fault(unsigned long addr, unsigned long esr,
 	 * find out access size.
 	 */
 	bool is_write = !!(esr & ESR_ELx_WNR);
-	kasan_report(addr, 0, is_write, regs->pc);
+	kasan_report((void *)addr, 0, is_write, regs->pc);
 }
 #else
 /* Tag faults aren't enabled without CONFIG_KASAN_HW_TAGS. */

include/linux/kasan.h +1 -1

index f7ef70661ce2..819b6bc8ac08 100644
@@ -343,7 +343,7 @@ static inline void *kasan_reset_tag(const void *addr)
  * @is_write: whether the bad access is a write or a read
  * @ip: instruction pointer for the accessibility check or the bad access itself
  */
-bool kasan_report(unsigned long addr, size_t size,
+bool kasan_report(const void *addr, size_t size,
 		bool is_write, unsigned long ip);
 
 #else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */

mm/kasan/common.c +1 -1

index b376a5d055e5..256930da578a 100644
@@ -445,7 +445,7 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag
 bool __kasan_check_byte(const void *address, unsigned long ip)
 {
 	if (!kasan_byte_accessible(address)) {
-		kasan_report((unsigned long)address, 1, false, ip);
+		kasan_report(address, 1, false, ip);
 		return false;
 	}
 	return true;

mm/kasan/generic.c +36 ~~-36~~

214 lines not on this page · raw message

mm/kasan/kasan.h +80 ~~-80~~

196 lines not on this page · raw message

mm/kasan/report.c +8 -9

index 892a9dc9d4d3..84d9f3b37014 100644
@@ -211,7 +211,7 @@ static void start_report(unsigned long *flags, bool sync)
 	pr_err("==================================================================\n");
 }
 
-static void end_report(unsigned long *flags, void *addr)
+static void end_report(unsigned long *flags, const void *addr)
 {
 	if (addr)
 		trace_error_report_end(ERROR_DETECTOR_KASAN,

@@ -450,8 +450,8 @@ static void print_memory_metadata(const void *addr)
 
 static void print_report(struct kasan_report_info *info)
 {
-	void *addr = kasan_reset_tag(info->access_addr);
-	u8 tag = get_tag(info->access_addr);
+	void *addr = kasan_reset_tag((void *)info->access_addr);
+	u8 tag = get_tag((void *)info->access_addr);
 
 	print_error_description(info);
 	if (addr_has_metadata(addr))

@@ -468,12 +468,12 @@ static void print_report(struct kasan_report_info *info)
 
 static void complete_report_info(struct kasan_report_info *info)
 {
-	void *addr = kasan_reset_tag(info->access_addr);
+	void *addr = kasan_reset_tag((void *)info->access_addr);
 	struct slab *slab;
 
 	if (info->type == KASAN_REPORT_ACCESS)
 		info->first_bad_addr = kasan_find_first_bad_addr(
-					info->access_addr, info->access_size);
+					(void *)info->access_addr, info->access_size);
 	else
 		info->first_bad_addr = addr;

@@ -544,11 +544,10 @@ void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_ty
  * user_access_save/restore(): kasan_report_invalid_free() cannot be called
  * from a UACCESS region, and kasan_report_async() is not used on x86.
  */
-bool kasan_report(unsigned long addr, size_t size, bool is_write,
+bool kasan_report(const void *addr, size_t size, bool is_write,
 			unsigned long ip)
 {
 	bool ret = true;
-	void *ptr = (void *)addr;
 	unsigned long ua_flags = user_access_save();
 	unsigned long irq_flags;
 	struct kasan_report_info info;

@@ -562,7 +561,7 @@ bool kasan_report(unsigned long addr, size_t size, bool is_write,
 
 	memset(&info, 0, sizeof(info));
 	info.type = KASAN_REPORT_ACCESS;
-	info.access_addr = ptr;
+	info.access_addr = addr;
 	info.access_size = size;
 	info.is_write = is_write;
 	info.ip = ip;

@@ -571,7 +570,7 @@ bool kasan_report(unsigned long addr, size_t size, bool is_write,
 
 	print_report(&info);
 
-	end_report(&irq_flags, ptr);
+	end_report(&irq_flags, (void *)addr);
 
 out:
 	user_access_restore(ua_flags);

mm/kasan/report_generic.c +6 -6

index 87d39bc0a673..51a1e8a8877f 100644
@@ -30,9 +30,9 @@
 #include "kasan.h"
 #include "../slab.h"
 
-void *kasan_find_first_bad_addr(void *addr, size_t size)
+const void *kasan_find_first_bad_addr(const void *addr, size_t size)
 {
-	void *p = addr;
+	const void *p = addr;
 
 	if (!addr_has_metadata(p))
 		return p;

@@ -362,14 +362,14 @@ void kasan_print_address_stack_frame(const void *addr)
 #endif /* CONFIG_KASAN_STACK */
 
 #define DEFINE_ASAN_REPORT_LOAD(size)                     \
-void __asan_report_load##size##_noabort(unsigned long addr) \
+void __asan_report_load##size##_noabort(void *addr) \
 {                                                         \
 	kasan_report(addr, size, false, _RET_IP_);	  \
 }                                                         \
 EXPORT_SYMBOL(__asan_report_load##size##_noabort)
 
 #define DEFINE_ASAN_REPORT_STORE(size)                     \
-void __asan_report_store##size##_noabort(unsigned long addr) \
+void __asan_report_store##size##_noabort(void *addr) \
 {                                                          \
 	kasan_report(addr, size, true, _RET_IP_);	   \
 }                                                          \

@@ -386,13 +386,13 @@ DEFINE_ASAN_REPORT_STORE(4);
 DEFINE_ASAN_REPORT_STORE(8);
 DEFINE_ASAN_REPORT_STORE(16);
 
-void __asan_report_load_n_noabort(unsigned long addr, size_t size)
+void __asan_report_load_n_noabort(void *addr, ssize_t size)
 {
 	kasan_report(addr, size, false, _RET_IP_);
 }
 EXPORT_SYMBOL(__asan_report_load_n_noabort);
 
-void __asan_report_store_n_noabort(unsigned long addr, size_t size)
+void __asan_report_store_n_noabort(void *addr, ssize_t size)
 {
 	kasan_report(addr, size, true, _RET_IP_);
 }

mm/kasan/report_hw_tags.c +1 -1

index 32e80f78de7d..065e1b2fc484 100644
@@ -15,7 +15,7 @@
 
 #include "kasan.h"
 
-void *kasan_find_first_bad_addr(void *addr, size_t size)
+const void *kasan_find_first_bad_addr(const void *addr, size_t size)
 {
 	/*
 	 * Hardware Tag-Based KASAN only calls this function for normal memory

mm/kasan/report_sw_tags.c +1 -1

index 8b1f5a73ee6d..689e94f9fe3c 100644
@@ -30,7 +30,7 @@
 #include "kasan.h"
 #include "../slab.h"
 
-void *kasan_find_first_bad_addr(void *addr, size_t size)
+const void *kasan_find_first_bad_addr(const void *addr, size_t size)
 {
 	u8 tag = get_tag(addr);
 	void *p = kasan_reset_tag(addr);

mm/kasan/shadow.c +18 ~~-18~~

index c8b86f3273b5..3e62728ae25d 100644
@@ -28,13 +28,13 @@
 
 bool __kasan_check_read(const volatile void *p, unsigned int size)
 {
-	return kasan_check_range((unsigned long)p, size, false, _RET_IP_);
+	return kasan_check_range((void *)p, size, false, _RET_IP_);
 }
 EXPORT_SYMBOL(__kasan_check_read);
 
 bool __kasan_check_write(const volatile void *p, unsigned int size)
 {
-	return kasan_check_range((unsigned long)p, size, true, _RET_IP_);
+	return kasan_check_range((void *)p, size, true, _RET_IP_);
 }
 EXPORT_SYMBOL(__kasan_check_write);

@@ -50,7 +50,7 @@ EXPORT_SYMBOL(__kasan_check_write);
 #undef memset
 void *memset(void *addr, int c, size_t len)
 {
-	if (!kasan_check_range((unsigned long)addr, len, true, _RET_IP_))
+	if (!kasan_check_range(addr, len, true, _RET_IP_))
 		return NULL;
 
 	return __memset(addr, c, len);

@@ -60,8 +60,8 @@ void *memset(void *addr, int c, size_t len)
 #undef memmove
 void *memmove(void *dest, const void *src, size_t len)
 {
-	if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
-	    !kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
+	if (!kasan_check_range(src, len, false, _RET_IP_) ||
+	    !kasan_check_range(dest, len, true, _RET_IP_))
 		return NULL;
 
 	return __memmove(dest, src, len);

@@ -71,17 +71,17 @@ void *memmove(void *dest, const void *src, size_t len)
 #undef memcpy
 void *memcpy(void *dest, const void *src, size_t len)
 {
-	if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
-	    !kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
+	if (!kasan_check_range(src, len, false, _RET_IP_) ||
+	    !kasan_check_range(dest, len, true, _RET_IP_))
 		return NULL;
 
 	return __memcpy(dest, src, len);
 }
 #endif
 
-void *__asan_memset(void *addr, int c, size_t len)
+void *__asan_memset(void *addr, int c, ssize_t len)
 {
-	if (!kasan_check_range((unsigned long)addr, len, true, _RET_IP_))
+	if (!kasan_check_range(addr, len, true, _RET_IP_))
 		return NULL;
 
 	return __memset(addr, c, len);

@@ -89,10 +89,10 @@ void *__asan_memset(void *addr, int c, size_t len)
 EXPORT_SYMBOL(__asan_memset);
 
 #ifdef __HAVE_ARCH_MEMMOVE
-void *__asan_memmove(void *dest, const void *src, size_t len)
+void *__asan_memmove(void *dest, const void *src, ssize_t len)
 {
-	if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
-	    !kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
+	if (!kasan_check_range(src, len, false, _RET_IP_) ||
+	    !kasan_check_range(dest, len, true, _RET_IP_))
 		return NULL;
 
 	return __memmove(dest, src, len);

@@ -100,10 +100,10 @@ void *__asan_memmove(void *dest, const void *src, size_t len)
 EXPORT_SYMBOL(__asan_memmove);
 #endif
 
-void *__asan_memcpy(void *dest, const void *src, size_t len)
+void *__asan_memcpy(void *dest, const void *src, ssize_t len)
 {
-	if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
-	    !kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
+	if (!kasan_check_range(src, len, false, _RET_IP_) ||
+	    !kasan_check_range(dest, len, true, _RET_IP_))
 		return NULL;
 
 	return __memcpy(dest, src, len);

@@ -111,13 +111,13 @@ void *__asan_memcpy(void *dest, const void *src, size_t len)
 EXPORT_SYMBOL(__asan_memcpy);
 
 #ifdef CONFIG_KASAN_SW_TAGS
-void *__hwasan_memset(void *addr, int c, size_t len) __alias(__asan_memset);
+void *__hwasan_memset(void *addr, int c, ssize_t len) __alias(__asan_memset);
 EXPORT_SYMBOL(__hwasan_memset);
 #ifdef __HAVE_ARCH_MEMMOVE
-void *__hwasan_memmove(void *dest, const void *src, size_t len) __alias(__asan_memmove);
+void *__hwasan_memmove(void *dest, const void *src, ssize_t len) __alias(__asan_memmove);
 EXPORT_SYMBOL(__hwasan_memmove);
 #endif
-void *__hwasan_memcpy(void *dest, const void *src, size_t len) __alias(__asan_memcpy);
+void *__hwasan_memcpy(void *dest, const void *src, ssize_t len) __alias(__asan_memcpy);
 EXPORT_SYMBOL(__hwasan_memcpy);
 #endif

mm/kasan/sw_tags.c +10 ~~-10~~

index 30da65fa02a1..220b5d4c6876 100644
@@ -70,8 +70,8 @@ u8 kasan_random_tag(void)
 	return (u8)(state % (KASAN_TAG_MAX + 1));
 }
 
-bool kasan_check_range(unsigned long addr, size_t size, bool write,
-				unsigned long ret_ip)
+bool kasan_check_range(const void *addr, size_t size, bool write,
+			unsigned long ret_ip)
 {
 	u8 tag;
 	u8 *shadow_first, *shadow_last, *shadow;

@@ -133,12 +133,12 @@ bool kasan_byte_accessible(const void *addr)
 }
 
 #define DEFINE_HWASAN_LOAD_STORE(size)					\
-	void __hwasan_load##size##_noabort(unsigned long addr)		\
+	void __hwasan_load##size##_noabort(void *addr)			\
 	{								\
-		kasan_check_range(addr, size, false, _RET_IP_);	\
+		kasan_check_range(addr, size, false, _RET_IP_);		\
 	}								\
 	EXPORT_SYMBOL(__hwasan_load##size##_noabort);			\
-	void __hwasan_store##size##_noabort(unsigned long addr)		\
+	void __hwasan_store##size##_noabort(void *addr)			\
 	{								\
 		kasan_check_range(addr, size, true, _RET_IP_);		\
 	}								\

@@ -150,25 +150,25 @@ DEFINE_HWASAN_LOAD_STORE(4);
 DEFINE_HWASAN_LOAD_STORE(8);
 DEFINE_HWASAN_LOAD_STORE(16);
 
-void __hwasan_loadN_noabort(unsigned long addr, unsigned long size)
+void __hwasan_loadN_noabort(void *addr, ssize_t size)
 {
 	kasan_check_range(addr, size, false, _RET_IP_);
 }
 EXPORT_SYMBOL(__hwasan_loadN_noabort);
 
-void __hwasan_storeN_noabort(unsigned long addr, unsigned long size)
+void __hwasan_storeN_noabort(void *addr, ssize_t size)
 {
 	kasan_check_range(addr, size, true, _RET_IP_);
 }
 EXPORT_SYMBOL(__hwasan_storeN_noabort);
 
-void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size)
+void __hwasan_tag_memory(void *addr, u8 tag, ssize_t size)
 {
-	kasan_poison((void *)addr, size, tag, false);
+	kasan_poison(addr, size, tag, false);
 }
 EXPORT_SYMBOL(__hwasan_tag_memory);
 
-void kasan_tag_mismatch(unsigned long addr, unsigned long access_info,
+void kasan_tag_mismatch(void *addr, unsigned long access_info,
 			unsigned long ret_ip)
 {
 	kasan_report(addr, 1 << (access_info & 0xf), access_info & 0x10,

Signature · 1 line

2.35.1

Andrew Morton

maintainer

2023-05-12 23:50 UTC #2 lore raw

Re: [PATCH 2/2] [v3] kasan: use internal prototypes matching gcc-13 builtins

Quoted 14 lines · On Tue, 9 May 2023 16:57:21 +0200 Arnd Bergmann <[email protected]> wrote:

gcc-13 warns about function definitions for builtin interfaces that have a different prototype, e.g.:
In file included from kasan_test.c:31:
kasan.h:574:6: error: conflicting types for built-in function '__asan_register_globals'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
574 | void __asan_register_globals(struct kasan_global *globals, size_t size);
kasan.h:577:6: error: conflicting types for built-in function '__asan_alloca_poison'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
577 | void __asan_alloca_poison(unsigned long addr, size_t size);
kasan.h:580:6: error: conflicting types for built-in function '__asan_load1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
580 | void __asan_load1(unsigned long addr);
kasan.h:581:6: error: conflicting types for built-in function '__asan_store1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
581 | void __asan_store1(unsigned long addr);
kasan.h:643:6: error: conflicting types for built-in function '__hwasan_tag_memory'; expected 'void(void *, unsigned char, long int)' [-Werror=builtin-declaration-mismatch]
643 | void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);

I added cc:stable to these, but staged them for the next merge window.

Because I expect many people will compile earlier kernels many times with gcc-13 and later, and they won't want to have to see these warnings all the time.