aeb7fa69dd
Remove obsolete patches for NL80211_ATTR_SMPS_MODE encoding and KRACK Fix CVE-2019-9494 (cache attack against SAE) Fix CVE-2019-9495 (cache attack against EAP-pwd) Fix CVE-2019-9496 (SAE confirm missing state validation in hostapd/AP) Fix CVE-2019-9497 (EAP-pwd server not checking for reflection attack) Fix CVE-2019-9498 (EAP-pwd server missing commit validation for scalar/element) Fix CVE-2019-9499 (EAP-pwd peer missing commit validation for scalar/element)
219 lines
6.5 KiB
Diff
219 lines
6.5 KiB
Diff
From 6e34f618d37ddbb5854c42e2ad4fca83492fa7b7 Mon Sep 17 00:00:00 2001
|
|
From: Jouni Malinen <jouni@codeaurora.org>
|
|
Date: Wed, 27 Feb 2019 18:38:30 +0200
|
|
Subject: [PATCH 02/14] Add helper functions for constant time operations
|
|
|
|
These functions can be used to help implement constant time operations
|
|
for various cryptographic operations that must minimize externally
|
|
observable differences in processing (both in timing and also in
|
|
internal cache use, etc.).
|
|
|
|
This is related to CVE-2019-9494 and CVE-2019-9495.
|
|
|
|
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
|
|
---
|
|
src/utils/const_time.h | 191 +++++++++++++++++++++++++++++++++++++++++++++++++
|
|
1 file changed, 191 insertions(+)
|
|
create mode 100644 src/utils/const_time.h
|
|
|
|
diff --git a/src/utils/const_time.h b/src/utils/const_time.h
|
|
new file mode 100644
|
|
index 0000000..ab8f611
|
|
--- /dev/null
|
|
+++ b/src/utils/const_time.h
|
|
@@ -0,0 +1,191 @@
|
|
+/*
|
|
+ * Helper functions for constant time operations
|
|
+ * Copyright (c) 2019, The Linux Foundation
|
|
+ *
|
|
+ * This software may be distributed under the terms of the BSD license.
|
|
+ * See README for more details.
|
|
+ *
|
|
+ * These helper functions can be used to implement logic that needs to minimize
|
|
+ * externally visible differences in execution path by avoiding use of branches,
|
|
+ * avoiding early termination or other time differences, and forcing same memory
|
|
+ * access pattern regardless of values.
|
|
+ */
|
|
+
|
|
+#ifndef CONST_TIME_H
|
|
+#define CONST_TIME_H
|
|
+
|
|
+
|
|
+#if defined(__clang__)
|
|
+#define NO_UBSAN_UINT_OVERFLOW \
|
|
+ __attribute__((no_sanitize("unsigned-integer-overflow")))
|
|
+#else
|
|
+#define NO_UBSAN_UINT_OVERFLOW
|
|
+#endif
|
|
+
|
|
+
|
|
+/**
|
|
+ * const_time_fill_msb - Fill all bits with MSB value
|
|
+ * @val: Input value
|
|
+ * Returns: Value with all the bits set to the MSB of the input val
|
|
+ */
|
|
+static inline unsigned int const_time_fill_msb(unsigned int val)
|
|
+{
|
|
+ /* Move the MSB to LSB and multiple by -1 to fill in all bits. */
|
|
+ return (val >> (sizeof(val) * 8 - 1)) * ~0U;
|
|
+}
|
|
+
|
|
+
|
|
+/* Returns: -1 if val is zero; 0 if val is not zero */
|
|
+static inline unsigned int const_time_is_zero(unsigned int val)
|
|
+ NO_UBSAN_UINT_OVERFLOW
|
|
+{
|
|
+ /* Set MSB to 1 for 0 and fill rest of bits with the MSB value */
|
|
+ return const_time_fill_msb(~val & (val - 1));
|
|
+}
|
|
+
|
|
+
|
|
+/* Returns: -1 if a == b; 0 if a != b */
|
|
+static inline unsigned int const_time_eq(unsigned int a, unsigned int b)
|
|
+{
|
|
+ return const_time_is_zero(a ^ b);
|
|
+}
|
|
+
|
|
+
|
|
+/* Returns: -1 if a == b; 0 if a != b */
|
|
+static inline u8 const_time_eq_u8(unsigned int a, unsigned int b)
|
|
+{
|
|
+ return (u8) const_time_eq(a, b);
|
|
+}
|
|
+
|
|
+
|
|
+/**
|
|
+ * const_time_eq_bin - Constant time memory comparison
|
|
+ * @a: First buffer to compare
|
|
+ * @b: Second buffer to compare
|
|
+ * @len: Number of octets to compare
|
|
+ * Returns: -1 if buffers are equal, 0 if not
|
|
+ *
|
|
+ * This function is meant for comparing passwords or hash values where
|
|
+ * difference in execution time or memory access pattern could provide external
|
|
+ * observer information about the location of the difference in the memory
|
|
+ * buffers. The return value does not behave like memcmp(), i.e.,
|
|
+ * const_time_eq_bin() cannot be used to sort items into a defined order. Unlike
|
|
+ * memcmp(), the execution time of const_time_eq_bin() does not depend on the
|
|
+ * contents of the compared memory buffers, but only on the total compared
|
|
+ * length.
|
|
+ */
|
|
+static inline unsigned int const_time_eq_bin(const void *a, const void *b,
|
|
+ size_t len)
|
|
+{
|
|
+ const u8 *aa = a;
|
|
+ const u8 *bb = b;
|
|
+ size_t i;
|
|
+ u8 res = 0;
|
|
+
|
|
+ for (i = 0; i < len; i++)
|
|
+ res |= aa[i] ^ bb[i];
|
|
+
|
|
+ return const_time_is_zero(res);
|
|
+}
|
|
+
|
|
+
|
|
+/**
|
|
+ * const_time_select - Constant time unsigned int selection
|
|
+ * @mask: 0 (false) or -1 (true) to identify which value to select
|
|
+ * @true_val: Value to select for the true case
|
|
+ * @false_val: Value to select for the false case
|
|
+ * Returns: true_val if mask == -1, false_val if mask == 0
|
|
+ */
|
|
+static inline unsigned int const_time_select(unsigned int mask,
|
|
+ unsigned int true_val,
|
|
+ unsigned int false_val)
|
|
+{
|
|
+ return (mask & true_val) | (~mask & false_val);
|
|
+}
|
|
+
|
|
+
|
|
+/**
|
|
+ * const_time_select_int - Constant time int selection
|
|
+ * @mask: 0 (false) or -1 (true) to identify which value to select
|
|
+ * @true_val: Value to select for the true case
|
|
+ * @false_val: Value to select for the false case
|
|
+ * Returns: true_val if mask == -1, false_val if mask == 0
|
|
+ */
|
|
+static inline int const_time_select_int(unsigned int mask, int true_val,
|
|
+ int false_val)
|
|
+{
|
|
+ return (int) const_time_select(mask, (unsigned int) true_val,
|
|
+ (unsigned int) false_val);
|
|
+}
|
|
+
|
|
+
|
|
+/**
|
|
+ * const_time_select_u8 - Constant time u8 selection
|
|
+ * @mask: 0 (false) or -1 (true) to identify which value to select
|
|
+ * @true_val: Value to select for the true case
|
|
+ * @false_val: Value to select for the false case
|
|
+ * Returns: true_val if mask == -1, false_val if mask == 0
|
|
+ */
|
|
+static inline u8 const_time_select_u8(u8 mask, u8 true_val, u8 false_val)
|
|
+{
|
|
+ return (u8) const_time_select(mask, true_val, false_val);
|
|
+}
|
|
+
|
|
+
|
|
+/**
|
|
+ * const_time_select_s8 - Constant time s8 selection
|
|
+ * @mask: 0 (false) or -1 (true) to identify which value to select
|
|
+ * @true_val: Value to select for the true case
|
|
+ * @false_val: Value to select for the false case
|
|
+ * Returns: true_val if mask == -1, false_val if mask == 0
|
|
+ */
|
|
+static inline s8 const_time_select_s8(u8 mask, s8 true_val, s8 false_val)
|
|
+{
|
|
+ return (s8) const_time_select(mask, (unsigned int) true_val,
|
|
+ (unsigned int) false_val);
|
|
+}
|
|
+
|
|
+
|
|
+/**
|
|
+ * const_time_select_bin - Constant time binary buffer selection copy
|
|
+ * @mask: 0 (false) or -1 (true) to identify which value to copy
|
|
+ * @true_val: Buffer to copy for the true case
|
|
+ * @false_val: Buffer to copy for the false case
|
|
+ * @len: Number of octets to copy
|
|
+ * @dst: Destination buffer for the copy
|
|
+ *
|
|
+ * This function copies the specified buffer into the destination buffer using
|
|
+ * operations with identical memory access pattern regardless of which buffer
|
|
+ * is being copied.
|
|
+ */
|
|
+static inline void const_time_select_bin(u8 mask, const u8 *true_val,
|
|
+ const u8 *false_val, size_t len,
|
|
+ u8 *dst)
|
|
+{
|
|
+ size_t i;
|
|
+
|
|
+ for (i = 0; i < len; i++)
|
|
+ dst[i] = const_time_select_u8(mask, true_val[i], false_val[i]);
|
|
+}
|
|
+
|
|
+
|
|
+static inline int const_time_memcmp(const void *a, const void *b, size_t len)
|
|
+{
|
|
+ const u8 *aa = a;
|
|
+ const u8 *bb = b;
|
|
+ int diff, res = 0;
|
|
+ unsigned int mask;
|
|
+
|
|
+ if (len == 0)
|
|
+ return 0;
|
|
+ do {
|
|
+ len--;
|
|
+ diff = (int) aa[len] - (int) bb[len];
|
|
+ mask = const_time_is_zero((unsigned int) diff);
|
|
+ res = const_time_select_int(mask, res, diff);
|
|
+ } while (len);
|
|
+
|
|
+ return res;
|
|
+}
|
|
+
|
|
+#endif /* CONST_TIME_H */
|
|
--
|
|
2.7.4
|
|
|