#endif
}
+/*
+ * On 64-bit architectures, protect against non-terminated C string overflows
+ * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
+ */
+#ifdef CONFIG_64BIT
+# ifdef __LITTLE_ENDIAN
+# define CANARY_MASK 0xffffffffffffff00UL
+# else /* big endian, 64 bits: */
+# define CANARY_MASK 0x00ffffffffffffffUL
+# endif
+#else /* 32 bits: */
+# define CANARY_MASK 0xffffffffUL
+#endif
+
+static inline unsigned long get_random_canary(void)
+{
+ unsigned long val = get_random_long();
+
+ return val & CANARY_MASK;
+}
+
+ /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
+ * Returns the result of the call to wait_for_random_bytes. */
+ static inline int get_random_bytes_wait(void *buf, int nbytes)
+ {
+ int ret = wait_for_random_bytes();
+ if (unlikely(ret))
+ return ret;
+ get_random_bytes(buf, nbytes);
+ return 0;
+ }
+
+ #define declare_get_random_var_wait(var) \
+ static inline int get_random_ ## var ## _wait(var *out) { \
+ int ret = wait_for_random_bytes(); \
+ if (unlikely(ret)) \
+ return ret; \
+ *out = get_random_ ## var(); \
+ return 0; \
+ }
+ declare_get_random_var_wait(u32)
+ declare_get_random_var_wait(u64)
+ declare_get_random_var_wait(int)
+ declare_get_random_var_wait(long)
+ #undef declare_get_random_var
+
unsigned long randomize_page(unsigned long start, unsigned long range);
u32 prandom_u32(void);