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-rw-r--r--arch/Kconfig6
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/include/asm/string.h5
-rw-r--r--arch/powerpc/Kconfig1
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/boot/compressed/misc.c5
-rw-r--r--arch/x86/include/asm/string_32.h9
-rw-r--r--arch/x86/include/asm/string_64.h7
-rw-r--r--arch/x86/lib/memcpy_32.c2
-rw-r--r--include/linux/string.h200
-rw-r--r--lib/string.c7
-rw-r--r--security/Kconfig7
12 files changed, 250 insertions, 1 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index fb9bd7d36b05..21d0089117fe 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -223,6 +223,12 @@ config GENERIC_SMP_IDLE_THREAD
config GENERIC_IDLE_POLL_SETUP
bool
+config ARCH_HAS_FORTIFY_SOURCE
+ bool
+ help
+ An architecture should select this when it can successfully
+ build and run with CONFIG_FORTIFY_SOURCE.
+
# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
config ARCH_HAS_SET_MEMORY
bool
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 8addb851ab5e..dfd908630631 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -12,6 +12,7 @@ config ARM64
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_ELF_RANDOMIZE
+ select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
select ARCH_HAS_KCOV
diff --git a/arch/arm64/include/asm/string.h b/arch/arm64/include/asm/string.h
index 2eb714c4639f..d0aa42907569 100644
--- a/arch/arm64/include/asm/string.h
+++ b/arch/arm64/include/asm/string.h
@@ -63,6 +63,11 @@ extern int memcmp(const void *, const void *, size_t);
#define memcpy(dst, src, len) __memcpy(dst, src, len)
#define memmove(dst, src, len) __memmove(dst, src, len)
#define memset(s, c, n) __memset(s, c, n)
+
+#ifndef __NO_FORTIFY
+#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
+#endif
+
#endif
#endif
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index fce2f4f20891..36f858c37ca7 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -125,6 +125,7 @@ config PPC
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_DMA_SET_COHERENT_MASK
select ARCH_HAS_ELF_RANDOMIZE
+ select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE
select ARCH_HAS_SG_CHAIN
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 3d2b8ce54e00..781521b7cf9e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -50,6 +50,7 @@ config X86
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
+ select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_KCOV if X86_64
select ARCH_HAS_MMIO_FLUSH
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 00241c815524..a0838ab929f2 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -411,3 +411,8 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
debug_putstr("done.\nBooting the kernel.\n");
return output;
}
+
+void fortify_panic(const char *name)
+{
+ error("detected buffer overflow");
+}
diff --git a/arch/x86/include/asm/string_32.h b/arch/x86/include/asm/string_32.h
index 3d3e8353ee5c..e9ee84873de5 100644
--- a/arch/x86/include/asm/string_32.h
+++ b/arch/x86/include/asm/string_32.h
@@ -142,7 +142,9 @@ static __always_inline void *__constant_memcpy(void *to, const void *from,
}
#define __HAVE_ARCH_MEMCPY
+extern void *memcpy(void *, const void *, size_t);
+#ifndef CONFIG_FORTIFY_SOURCE
#ifdef CONFIG_X86_USE_3DNOW
#include <asm/mmx.h>
@@ -195,11 +197,15 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len)
#endif
#endif
+#endif /* !CONFIG_FORTIFY_SOURCE */
#define __HAVE_ARCH_MEMMOVE
void *memmove(void *dest, const void *src, size_t n);
+extern int memcmp(const void *, const void *, size_t);
+#ifndef CONFIG_FORTIFY_SOURCE
#define memcmp __builtin_memcmp
+#endif
#define __HAVE_ARCH_MEMCHR
extern void *memchr(const void *cs, int c, size_t count);
@@ -321,6 +327,8 @@ void *__constant_c_and_count_memset(void *s, unsigned long pattern,
: __memset_generic((s), (c), (count)))
#define __HAVE_ARCH_MEMSET
+extern void *memset(void *, int, size_t);
+#ifndef CONFIG_FORTIFY_SOURCE
#if (__GNUC__ >= 4)
#define memset(s, c, count) __builtin_memset(s, c, count)
#else
@@ -330,6 +338,7 @@ void *__constant_c_and_count_memset(void *s, unsigned long pattern,
(count)) \
: __memset((s), (c), (count)))
#endif
+#endif /* !CONFIG_FORTIFY_SOURCE */
/*
* find the first occurrence of byte 'c', or 1 past the area if none
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index 1f22bc277c45..2a8c822de1fc 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -31,6 +31,7 @@ static __always_inline void *__inline_memcpy(void *to, const void *from, size_t
extern void *memcpy(void *to, const void *from, size_t len);
extern void *__memcpy(void *to, const void *from, size_t len);
+#ifndef CONFIG_FORTIFY_SOURCE
#ifndef CONFIG_KMEMCHECK
#if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
#define memcpy(dst, src, len) \
@@ -51,6 +52,7 @@ extern void *__memcpy(void *to, const void *from, size_t len);
*/
#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
#endif
+#endif /* !CONFIG_FORTIFY_SOURCE */
#define __HAVE_ARCH_MEMSET
void *memset(void *s, int c, size_t n);
@@ -77,6 +79,11 @@ int strcmp(const char *cs, const char *ct);
#define memcpy(dst, src, len) __memcpy(dst, src, len)
#define memmove(dst, src, len) __memmove(dst, src, len)
#define memset(s, c, n) __memset(s, c, n)
+
+#ifndef __NO_FORTIFY
+#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
+#endif
+
#endif
#define __HAVE_ARCH_MEMCPY_MCSAFE 1
diff --git a/arch/x86/lib/memcpy_32.c b/arch/x86/lib/memcpy_32.c
index cad12634d6bd..2eab7d0bfedd 100644
--- a/arch/x86/lib/memcpy_32.c
+++ b/arch/x86/lib/memcpy_32.c
@@ -6,7 +6,7 @@
__visible void *memcpy(void *to, const void *from, size_t n)
{
-#ifdef CONFIG_X86_USE_3DNOW
+#if defined(CONFIG_X86_USE_3DNOW) && !defined(CONFIG_FORTIFY_SOURCE)
return __memcpy3d(to, from, n);
#else
return __memcpy(to, from, n);
diff --git a/include/linux/string.h b/include/linux/string.h
index 7439d83eaa33..96f5a5fd0377 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -193,4 +193,204 @@ static inline const char *kbasename(const char *path)
return tail ? tail + 1 : path;
}
+#define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
+#define __RENAME(x) __asm__(#x)
+
+void fortify_panic(const char *name) __noreturn __cold;
+void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
+void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
+void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
+
+#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
+__FORTIFY_INLINE char *strcpy(char *p, const char *q)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ size_t q_size = __builtin_object_size(q, 0);
+ if (p_size == (size_t)-1 && q_size == (size_t)-1)
+ return __builtin_strcpy(p, q);
+ if (strscpy(p, q, p_size < q_size ? p_size : q_size) < 0)
+ fortify_panic(__func__);
+ return p;
+}
+
+__FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ if (__builtin_constant_p(size) && p_size < size)
+ __write_overflow();
+ if (p_size < size)
+ fortify_panic(__func__);
+ return __builtin_strncpy(p, q, size);
+}
+
+__FORTIFY_INLINE char *strcat(char *p, const char *q)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ if (p_size == (size_t)-1)
+ return __builtin_strcat(p, q);
+ if (strlcat(p, q, p_size) >= p_size)
+ fortify_panic(__func__);
+ return p;
+}
+
+__FORTIFY_INLINE __kernel_size_t strlen(const char *p)
+{
+ __kernel_size_t ret;
+ size_t p_size = __builtin_object_size(p, 0);
+ if (p_size == (size_t)-1)
+ return __builtin_strlen(p);
+ ret = strnlen(p, p_size);
+ if (p_size <= ret)
+ fortify_panic(__func__);
+ return ret;
+}
+
+extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
+__FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
+ if (p_size <= ret && maxlen != ret)
+ fortify_panic(__func__);
+ return ret;
+}
+
+/* defined after fortified strlen to reuse it */
+extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
+__FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
+{
+ size_t ret;
+ size_t p_size = __builtin_object_size(p, 0);
+ size_t q_size = __builtin_object_size(q, 0);
+ if (p_size == (size_t)-1 && q_size == (size_t)-1)
+ return __real_strlcpy(p, q, size);
+ ret = strlen(q);
+ if (size) {
+ size_t len = (ret >= size) ? size - 1 : ret;
+ if (__builtin_constant_p(len) && len >= p_size)
+ __write_overflow();
+ if (len >= p_size)
+ fortify_panic(__func__);
+ __builtin_memcpy(p, q, len);
+ p[len] = '\0';
+ }
+ return ret;
+}
+
+/* defined after fortified strlen and strnlen to reuse them */
+__FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
+{
+ size_t p_len, copy_len;
+ size_t p_size = __builtin_object_size(p, 0);
+ size_t q_size = __builtin_object_size(q, 0);
+ if (p_size == (size_t)-1 && q_size == (size_t)-1)
+ return __builtin_strncat(p, q, count);
+ p_len = strlen(p);
+ copy_len = strnlen(q, count);
+ if (p_size < p_len + copy_len + 1)
+ fortify_panic(__func__);
+ __builtin_memcpy(p + p_len, q, copy_len);
+ p[p_len + copy_len] = '\0';
+ return p;
+}
+
+__FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ if (__builtin_constant_p(size) && p_size < size)
+ __write_overflow();
+ if (p_size < size)
+ fortify_panic(__func__);
+ return __builtin_memset(p, c, size);
+}
+
+__FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ size_t q_size = __builtin_object_size(q, 0);
+ if (__builtin_constant_p(size)) {
+ if (p_size < size)
+ __write_overflow();
+ if (q_size < size)
+ __read_overflow2();
+ }
+ if (p_size < size || q_size < size)
+ fortify_panic(__func__);
+ return __builtin_memcpy(p, q, size);
+}
+
+__FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ size_t q_size = __builtin_object_size(q, 0);
+ if (__builtin_constant_p(size)) {
+ if (p_size < size)
+ __write_overflow();
+ if (q_size < size)
+ __read_overflow2();
+ }
+ if (p_size < size || q_size < size)
+ fortify_panic(__func__);
+ return __builtin_memmove(p, q, size);
+}
+
+extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
+__FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ if (__builtin_constant_p(size) && p_size < size)
+ __read_overflow();
+ if (p_size < size)
+ fortify_panic(__func__);
+ return __real_memscan(p, c, size);
+}
+
+__FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ size_t q_size = __builtin_object_size(q, 0);
+ if (__builtin_constant_p(size)) {
+ if (p_size < size)
+ __read_overflow();
+ if (q_size < size)
+ __read_overflow2();
+ }
+ if (p_size < size || q_size < size)
+ fortify_panic(__func__);
+ return __builtin_memcmp(p, q, size);
+}
+
+__FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ if (__builtin_constant_p(size) && p_size < size)
+ __read_overflow();
+ if (p_size < size)
+ fortify_panic(__func__);
+ return __builtin_memchr(p, c, size);
+}
+
+void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
+__FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ if (__builtin_constant_p(size) && p_size < size)
+ __read_overflow();
+ if (p_size < size)
+ fortify_panic(__func__);
+ return __real_memchr_inv(p, c, size);
+}
+
+extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
+__FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
+{
+ size_t p_size = __builtin_object_size(p, 0);
+ if (__builtin_constant_p(size) && p_size < size)
+ __read_overflow();
+ if (p_size < size)
+ fortify_panic(__func__);
+ return __real_kmemdup(p, size, gfp);
+}
+#endif
+
#endif /* _LINUX_STRING_H_ */
diff --git a/lib/string.c b/lib/string.c
index 1c1fc9187b05..ebbb99c775bd 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -978,3 +978,10 @@ char *strreplace(char *s, char old, char new)
return s;
}
EXPORT_SYMBOL(strreplace);
+
+void fortify_panic(const char *name)
+{
+ pr_emerg("detected buffer overflow in %s\n", name);
+ BUG();
+}
+EXPORT_SYMBOL(fortify_panic);
diff --git a/security/Kconfig b/security/Kconfig
index d540bfe73190..e8e449444e65 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -163,6 +163,13 @@ config HARDENED_USERCOPY_PAGESPAN
been removed. This config is intended to be used only while
trying to find such users.
+config FORTIFY_SOURCE
+ bool "Harden common str/mem functions against buffer overflows"
+ depends on ARCH_HAS_FORTIFY_SOURCE
+ help
+ Detect overflows of buffers in common string and memory functions
+ where the compiler can determine and validate the buffer sizes.
+
config STATIC_USERMODEHELPER
bool "Force all usermode helper calls through a single binary"
help