[v4.4,V2,09/43] mm/kasan: add API to check memory regions

Commit Message

Viresh Kumar July 12, 2019, 5:27 a.m. UTC

From: Andrey Ryabinin <[e-mail]>

commit 64f8ebaf115bcddc4aaa902f981c57ba6506bc42 upstream.

Memory access coded in an assembly won't be seen by KASAN as a compiler
can instrument only C code.  Add kasan_check_[read,write]() API which is
going to be used to check a certain memory range.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Andrey Ryabinin <[e-mail]>
Acked-by: Alexander Potapenko <[e-mail]>
Cc: Dmitry Vyukov <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>
[ v4.4: Fixed MAINTAINERS conflict and added whole kasan entry. Drop 4th
	argument to check_memory_region(). ]
Signed-off-by: Viresh Kumar <[e-mail]>
---
 MAINTAINERS                  | 14 ++++++++++++++
 include/linux/kasan-checks.h | 12 ++++++++++++
 mm/kasan/kasan.c             | 12 ++++++++++++
 3 files changed, 38 insertions(+)
 create mode 100644 include/linux/kasan-checks.h

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index f4d4a5544dc1..2a8826732967 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5982,6 +5982,20 @@  S:	Maintained
 F:	Documentation/hwmon/k8temp
 F:	drivers/hwmon/k8temp.c
 
+KASAN
+M:	Andrey Ryabinin <[e-mail]>
+R:	Alexander Potapenko <[e-mail]>
+R:	Dmitry Vyukov <[e-mail]>
+L:	[e-mail]
+S:	Maintained
+F:	arch/*/include/asm/kasan.h
+F:	arch/*/mm/kasan_init*
+F:	Documentation/kasan.txt
+F:	include/linux/kasan*.h
+F:	lib/test_kasan.c
+F:	mm/kasan/
+F:	scripts/Makefile.kasan
+
 KCONFIG
 M:	"Yann E. MORIN" <[e-mail]>
 L:	[e-mail]
diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
new file mode 100644
index 000000000000..b7f8aced7870
--- /dev/null
+++ b/include/linux/kasan-checks.h
@@ -0,0 +1,12 @@ 
+#ifndef _LINUX_KASAN_CHECKS_H
+#define _LINUX_KASAN_CHECKS_H
+
+#ifdef CONFIG_KASAN
+void kasan_check_read(const void *p, unsigned int size);
+void kasan_check_write(const void *p, unsigned int size);
+#else
+static inline void kasan_check_read(const void *p, unsigned int size) { }
+static inline void kasan_check_write(const void *p, unsigned int size) { }
+#endif
+
+#endif
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index b7397b459960..1cdcab0c976a 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -274,6 +274,18 @@  static __always_inline void check_memory_region(unsigned long addr,
 void __asan_loadN(unsigned long addr, size_t size);
 void __asan_storeN(unsigned long addr, size_t size);
 
+void kasan_check_read(const void *p, unsigned int size)
+{
+	check_memory_region((unsigned long)p, size, false);
+}
+EXPORT_SYMBOL(kasan_check_read);
+
+void kasan_check_write(const void *p, unsigned int size)
+{
+	check_memory_region((unsigned long)p, size, true);
+}
+EXPORT_SYMBOL(kasan_check_write);
+
 #undef memset
 void *memset(void *addr, int c, size_t len)
 {