1 files changed, 87 insertions, 112 deletions

diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index f7e1895367fa..0d99bf11d260 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_FORTIFY_STRING_H_
 #define _LINUX_FORTIFY_STRING_H_
 
+#include <linux/bitfield.h>
 #include <linux/bug.h>
 #include <linux/const.h>
 #include <linux/limits.h>
@@ -9,7 +10,50 @@
 #define __FORTIFY_INLINE extern __always_inline __gnu_inline __overloadable
 #define __RENAME(x) __asm__(#x)
 
-void fortify_panic(const char *name) __noreturn __cold;
+#define FORTIFY_REASON_DIR(r)		FIELD_GET(BIT(0), r)
+#define FORTIFY_REASON_FUNC(r)		FIELD_GET(GENMASK(7, 1), r)
+#define FORTIFY_REASON(func, write)	(FIELD_PREP(BIT(0), write) | \
+					 FIELD_PREP(GENMASK(7, 1), func))
+
+/* Overridden by KUnit tests. */
+#ifndef fortify_panic
+# define fortify_panic(func, write, avail, size, retfail)	\
+	 __fortify_panic(FORTIFY_REASON(func, write), avail, size)
+#endif
+#ifndef fortify_warn_once
+# define fortify_warn_once(x...)	WARN_ONCE(x)
+#endif
+
+#define FORTIFY_READ		 0
+#define FORTIFY_WRITE		 1
+
+#define EACH_FORTIFY_FUNC(macro)	\
+	macro(strncpy),			\
+	macro(strnlen),			\
+	macro(strlen),			\
+	macro(strscpy),			\
+	macro(strlcat),			\
+	macro(strcat),			\
+	macro(strncat),			\
+	macro(memset),			\
+	macro(memcpy),			\
+	macro(memmove),			\
+	macro(memscan),			\
+	macro(memcmp),			\
+	macro(memchr),			\
+	macro(memchr_inv),		\
+	macro(kmemdup),			\
+	macro(strcpy),			\
+	macro(UNKNOWN),
+
+#define MAKE_FORTIFY_FUNC(func)	FORTIFY_FUNC_##func
+
+enum fortify_func {
+	EACH_FORTIFY_FUNC(MAKE_FORTIFY_FUNC)
+};
+
+void __fortify_report(const u8 reason, const size_t avail, const size_t size);
+void __fortify_panic(const u8 reason, const size_t avail, const size_t size) __cold __noreturn;
 void __read_overflow(void) __compiletime_error("detected read beyond size of object (1st parameter)");
 void __read_overflow2(void) __compiletime_error("detected read beyond size of object (2nd parameter)");
 void __read_overflow2_field(size_t avail, size_t wanted) __compiletime_warning("detected read beyond size of field (2nd parameter); maybe use struct_group()?");
@@ -107,13 +151,9 @@ extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size)
 #if __has_builtin(__builtin_dynamic_object_size)
 #define POS			__pass_dynamic_object_size(1)
 #define POS0			__pass_dynamic_object_size(0)
-#define __struct_size(p)	__builtin_dynamic_object_size(p, 0)
-#define __member_size(p)	__builtin_dynamic_object_size(p, 1)
 #else
 #define POS			__pass_object_size(1)
 #define POS0			__pass_object_size(0)
-#define __struct_size(p)	__builtin_object_size(p, 0)
-#define __member_size(p)	__builtin_object_size(p, 1)
 #endif
 
 #define __compiletime_lessthan(bounds, length)	(	\
@@ -161,7 +201,7 @@ char *strncpy(char * const POS p, const char *q, __kernel_size_t size)
 	if (__compiletime_lessthan(p_size, size))
 		__write_overflow();
 	if (p_size < size)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_strncpy, FORTIFY_WRITE, p_size, size, p);
 	return __underlying_strncpy(p, q, size);
 }
 
@@ -192,7 +232,7 @@ __FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size
 	/* Do not check characters beyond the end of p. */
 	ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
 	if (p_size <= ret && maxlen != ret)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_strnlen, FORTIFY_READ, p_size, ret + 1, ret);
 	return ret;
 }
 
@@ -228,82 +268,13 @@ __kernel_size_t __fortify_strlen(const char * const POS p)
 		return __underlying_strlen(p);
 	ret = strnlen(p, p_size);
 	if (p_size <= ret)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_strlen, FORTIFY_READ, p_size, ret + 1, ret);
 	return ret;
 }
 
-/* Defined after fortified strlen() to reuse it. */
-extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
-/**
- * strlcpy - Copy a string into another string buffer
- *
- * @p: pointer to destination of copy
- * @q: pointer to NUL-terminated source string to copy
- * @size: maximum number of bytes to write at @p
- *
- * If strlen(@q) >= @size, the copy of @q will be truncated at
- * @size - 1 bytes. @p will always be NUL-terminated.
- *
- * Do not use this function. While FORTIFY_SOURCE tries to avoid
- * over-reads when calculating strlen(@q), it is still possible.
- * Prefer strscpy(), though note its different return values for
- * detecting truncation.
- *
- * Returns total number of bytes written to @p, including terminating NUL.
- *
- */
-__FORTIFY_INLINE size_t strlcpy(char * const POS p, const char * const POS q, size_t size)
-{
-	const size_t p_size = __member_size(p);
-	const size_t q_size = __member_size(q);
-	size_t q_len;	/* Full count of source string length. */
-	size_t len;	/* Count of characters going into destination. */
-
-	if (p_size == SIZE_MAX && q_size == SIZE_MAX)
-		return __real_strlcpy(p, q, size);
-	q_len = strlen(q);
-	len = (q_len >= size) ? size - 1 : q_len;
-	if (__builtin_constant_p(size) && __builtin_constant_p(q_len) && size) {
-		/* Write size is always larger than destination. */
-		if (len >= p_size)
-			__write_overflow();
-	}
-	if (size) {
-		if (len >= p_size)
-			fortify_panic(__func__);
-		__underlying_memcpy(p, q, len);
-		p[len] = '\0';
-	}
-	return q_len;
-}
-
 /* Defined after fortified strnlen() to reuse it. */
-extern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(strscpy);
-/**
- * strscpy - Copy a C-string into a sized buffer
- *
- * @p: Where to copy the string to
- * @q: Where to copy the string from
- * @size: Size of destination buffer
- *
- * Copy the source string @q, or as much of it as fits, into the destination
- * @p buffer. The behavior is undefined if the string buffers overlap. The
- * destination @p buffer is always NUL terminated, unless it's zero-sized.
- *
- * Preferred to strlcpy() since the API doesn't require reading memory
- * from the source @q string beyond the specified @size bytes, and since
- * the return value is easier to error-check than strlcpy()'s.
- * In addition, the implementation is robust to the string changing out
- * from underneath it, unlike the current strlcpy() implementation.
- *
- * Preferred to strncpy() since it always returns a valid string, and
- * doesn't unnecessarily force the tail of the destination buffer to be
- * zero padded. If padding is desired please use strscpy_pad().
- *
- * Returns the number of characters copied in @p (not including the
- * trailing %NUL) or -E2BIG if @size is 0 or the copy of @q was truncated.
- */
-__FORTIFY_INLINE ssize_t strscpy(char * const POS p, const char * const POS q, size_t size)
+extern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(sized_strscpy);
+__FORTIFY_INLINE ssize_t sized_strscpy(char * const POS p, const char * const POS q, size_t size)
 {
 	/* Use string size rather than possible enclosing struct size. */
 	const size_t p_size = __member_size(p);
@@ -347,8 +318,8 @@ __FORTIFY_INLINE ssize_t strscpy(char * const POS p, const char * const POS q, s
 	 * Generate a runtime write overflow error if len is greater than
 	 * p_size.
 	 */
-	if (len > p_size)
-		fortify_panic(__func__);
+	if (p_size < len)
+		fortify_panic(FORTIFY_FUNC_strscpy, FORTIFY_WRITE, p_size, len, -E2BIG);
 
 	/*
 	 * We can now safely call vanilla strscpy because we are protected from:
@@ -406,7 +377,7 @@ size_t strlcat(char * const POS p, const char * const POS q, size_t avail)
 
 	/* Give up if string is already overflowed. */
 	if (p_size <= p_len)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_strlcat, FORTIFY_READ, p_size, p_len + 1, wanted);
 
 	if (actual >= avail) {
 		copy_len = avail - p_len - 1;
@@ -415,7 +386,7 @@ size_t strlcat(char * const POS p, const char * const POS q, size_t avail)
 
 	/* Give up if copy will overflow. */
 	if (p_size <= actual)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_strlcat, FORTIFY_WRITE, p_size, actual + 1, wanted);
 	__underlying_memcpy(p + p_len, q, copy_len);
 	p[actual] = '\0';
 
@@ -442,9 +413,10 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)
 char *strcat(char * const POS p, const char *q)
 {
 	const size_t p_size = __member_size(p);
+	const size_t wanted = strlcat(p, q, p_size);
 
-	if (strlcat(p, q, p_size) >= p_size)
-		fortify_panic(__func__);
+	if (p_size <= wanted)
+		fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);
 	return p;
 }
 
@@ -473,20 +445,21 @@ char *strncat(char * const POS p, const char * const POS q, __kernel_size_t coun
 {
 	const size_t p_size = __member_size(p);
 	const size_t q_size = __member_size(q);
-	size_t p_len, copy_len;
+	size_t p_len, copy_len, total;
 
 	if (p_size == SIZE_MAX && q_size == SIZE_MAX)
 		return __underlying_strncat(p, q, count);
 	p_len = strlen(p);
 	copy_len = strnlen(q, count);
-	if (p_size < p_len + copy_len + 1)
-		fortify_panic(__func__);
+	total = p_len + copy_len + 1;
+	if (p_size < total)
+		fortify_panic(FORTIFY_FUNC_strncat, FORTIFY_WRITE, p_size, total, p);
 	__underlying_memcpy(p + p_len, q, copy_len);
 	p[p_len + copy_len] = '\0';
 	return p;
 }
 
-__FORTIFY_INLINE void fortify_memset_chk(__kernel_size_t size,
+__FORTIFY_INLINE bool fortify_memset_chk(__kernel_size_t size,
 					 const size_t p_size,
 					 const size_t p_size_field)
 {
@@ -521,7 +494,8 @@ __FORTIFY_INLINE void fortify_memset_chk(__kernel_size_t size,
 	 * lengths are unknown.)
 	 */
 	if (p_size != SIZE_MAX && p_size < size)
-		fortify_panic("memset");
+		fortify_panic(FORTIFY_FUNC_memset, FORTIFY_WRITE, p_size, size, true);
+	return false;
 }
 
 #define __fortify_memset_chk(p, c, size, p_size, p_size_field) ({	\
@@ -575,7 +549,7 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
 					 const size_t q_size,
 					 const size_t p_size_field,
 					 const size_t q_size_field,
-					 const char *func)
+					 const u8 func)
 {
 	if (__builtin_constant_p(size)) {
 		/*
@@ -619,18 +593,15 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
 	 * (The SIZE_MAX test is to optimize away checks where the buffer
 	 * lengths are unknown.)
 	 */
-	if ((p_size != SIZE_MAX && p_size < size) ||
-	    (q_size != SIZE_MAX && q_size < size))
-		fortify_panic(func);
+	if (p_size != SIZE_MAX && p_size < size)
+		fortify_panic(func, FORTIFY_WRITE, p_size, size, true);
+	else if (q_size != SIZE_MAX && q_size < size)
+		fortify_panic(func, FORTIFY_READ, p_size, size, true);
 
 	/*
 	 * Warn when writing beyond destination field size.
 	 *
-	 * We must ignore p_size_field == 0 for existing 0-element
-	 * fake flexible arrays, until they are all converted to
-	 * proper flexible arrays.
-	 *
-	 * The implementation of __builtin_*object_size() behaves
+	 * Note the implementation of __builtin_*object_size() behaves
 	 * like sizeof() when not directly referencing a flexible
 	 * array member, which means there will be many bounds checks
 	 * that will appear at run-time, without a way for them to be
@@ -638,7 +609,7 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
 	 * is specifically the flexible array member).
 	 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101832
 	 */
-	if (p_size_field != 0 && p_size_field != SIZE_MAX &&
+	if (p_size_field != SIZE_MAX &&
 	    p_size != p_size_field && p_size_field < size)
 		return true;
 
@@ -652,12 +623,12 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
 	const size_t __q_size = (q_size);				\
 	const size_t __p_size_field = (p_size_field);			\
 	const size_t __q_size_field = (q_size_field);			\
-	WARN_ONCE(fortify_memcpy_chk(__fortify_size, __p_size,		\
+	fortify_warn_once(fortify_memcpy_chk(__fortify_size, __p_size,	\
 				     __q_size, __p_size_field,		\
-				     __q_size_field, #op),		\
+				     __q_size_field, FORTIFY_FUNC_ ##op), \
 		  #op ": detected field-spanning write (size %zu) of single %s (size %zu)\n", \
 		  __fortify_size,					\
-		  "field \"" #p "\" at " __FILE__ ":" __stringify(__LINE__), \
+		  "field \"" #p "\" at " FILE_LINE,			\
 		  __p_size_field);					\
 	__underlying_##op(p, q, __fortify_size);			\
 })
@@ -721,7 +692,7 @@ __FORTIFY_INLINE void *memscan(void * const POS0 p, int c, __kernel_size_t size)
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
 	if (p_size < size)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_memscan, FORTIFY_READ, p_size, size, NULL);
 	return __real_memscan(p, c, size);
 }
 
@@ -737,8 +708,10 @@ int memcmp(const void * const POS0 p, const void * const POS0 q, __kernel_size_t
 		if (__compiletime_lessthan(q_size, size))
 			__read_overflow2();
 	}
-	if (p_size < size || q_size < size)
-		fortify_panic(__func__);
+	if (p_size < size)
+		fortify_panic(FORTIFY_FUNC_memcmp, FORTIFY_READ, p_size, size, INT_MIN);
+	else if (q_size < size)
+		fortify_panic(FORTIFY_FUNC_memcmp, FORTIFY_READ, q_size, size, INT_MIN);
 	return __underlying_memcmp(p, q, size);
 }
 
@@ -750,7 +723,7 @@ void *memchr(const void * const POS0 p, int c, __kernel_size_t size)
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
 	if (p_size < size)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_memchr, FORTIFY_READ, p_size, size, NULL);
 	return __underlying_memchr(p, c, size);
 }
 
@@ -762,22 +735,24 @@ __FORTIFY_INLINE void *memchr_inv(const void * const POS0 p, int c, size_t size)
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
 	if (p_size < size)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_memchr_inv, FORTIFY_READ, p_size, size, NULL);
 	return __real_memchr_inv(p, c, size);
 }
 
-extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup)
+extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup_noprof)
 								    __realloc_size(2);
-__FORTIFY_INLINE void *kmemdup(const void * const POS0 p, size_t size, gfp_t gfp)
+__FORTIFY_INLINE void *kmemdup_noprof(const void * const POS0 p, size_t size, gfp_t gfp)
 {
 	const size_t p_size = __struct_size(p);
 
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
 	if (p_size < size)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_kmemdup, FORTIFY_READ, p_size, size,
+			      __real_kmemdup(p, 0, gfp));
 	return __real_kmemdup(p, size, gfp);
 }
+#define kmemdup(...)	alloc_hooks(kmemdup_noprof(__VA_ARGS__))
 
 /**
  * strcpy - Copy a string into another string buffer
@@ -812,7 +787,7 @@ char *strcpy(char * const POS p, const char * const POS q)
 		__write_overflow();
 	/* Run-time check for dynamic size overflow. */
 	if (p_size < size)
-		fortify_panic(__func__);
+		fortify_panic(FORTIFY_FUNC_strcpy, FORTIFY_WRITE, p_size, size, p);
 	__underlying_memcpy(p, q, size);
 	return p;
 }