3.16.73-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: "Jason A. Donenfeld" Jason@zx2c4.com

commit 1ae2324f732c9c4e2fa4ebd885fa1001b70d52e1 upstream.

HalfSipHash, or hsiphash, is a shortened version of SipHash, which generates 32-bit outputs using a weaker 64-bit key. It has *much* lower security margins, and shouldn't be used for anything too sensitive, but it could be used as a hashtable key function replacement, if the output is never exposed, and if the security requirement is not too high.

The goal is to make this something that performance-critical jhash users would be willing to use.

On 64-bit machines, HalfSipHash1-3 is slower than SipHash1-3, so we alias SipHash1-3 to HalfSipHash1-3 on those systems.

64-bit x86_64: [ 0.509409] test_siphash: SipHash2-4 cycles: 4049181 [ 0.510650] test_siphash: SipHash1-3 cycles: 2512884 [ 0.512205] test_siphash: HalfSipHash1-3 cycles: 3429920 [ 0.512904] test_siphash: JenkinsHash cycles: 978267 So, we map hsiphash() -> SipHash1-3

32-bit x86: [ 0.509868] test_siphash: SipHash2-4 cycles: 14812892 [ 0.513601] test_siphash: SipHash1-3 cycles: 9510710 [ 0.515263] test_siphash: HalfSipHash1-3 cycles: 3856157 [ 0.515952] test_siphash: JenkinsHash cycles: 1148567 So, we map hsiphash() -> HalfSipHash1-3

hsiphash() is roughly 3 times slower than jhash(), but comes with a considerable security improvement.

Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Reviewed-by: Jean-Philippe Aumasson jeanphilippe.aumasson@gmail.com Signed-off-by: David S. Miller davem@davemloft.net [bwh: Backported to 3.16 to avoid a build regression for WireGuard with only part of the siphash API available] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- Documentation/siphash.txt | 75 +++++++++ include/linux/siphash.h | 57 ++++++- lib/siphash.c | 321 +++++++++++++++++++++++++++++++++++++- lib/test_siphash.c | 98 +++++++++++- 4 files changed, 546 insertions(+), 5 deletions(-)

--- a/Documentation/siphash.txt +++ b/Documentation/siphash.txt @@ -98,3 +98,78 @@ u64 h = siphash(&combined, offsetofend(t

Read the SipHash paper if you're interested in learning more: https://131002.net/siphash/siphash.pdf + + +~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~ + +HalfSipHash - SipHash's insecure younger cousin +----------------------------------------------- +Written by Jason A. Donenfeld jason@zx2c4.com + +On the off-chance that SipHash is not fast enough for your needs, you might be +able to justify using HalfSipHash, a terrifying but potentially useful +possibility. HalfSipHash cuts SipHash's rounds down from "2-4" to "1-3" and, +even scarier, uses an easily brute-forcable 64-bit key (with a 32-bit output) +instead of SipHash's 128-bit key. However, this may appeal to some +high-performance `jhash` users. + +Danger! + +Do not ever use HalfSipHash except for as a hashtable key function, and only +then when you can be absolutely certain that the outputs will never be +transmitted out of the kernel. This is only remotely useful over `jhash` as a +means of mitigating hashtable flooding denial of service attacks. + +1. Generating a key + +Keys should always be generated from a cryptographically secure source of +random numbers, either using get_random_bytes or get_random_once: + +hsiphash_key_t key; +get_random_bytes(&key, sizeof(key)); + +If you're not deriving your key from here, you're doing it wrong. + +2. Using the functions + +There are two variants of the function, one that takes a list of integers, and +one that takes a buffer: + +u32 hsiphash(const void *data, size_t len, const hsiphash_key_t *key); + +And: + +u32 hsiphash_1u32(u32, const hsiphash_key_t *key); +u32 hsiphash_2u32(u32, u32, const hsiphash_key_t *key); +u32 hsiphash_3u32(u32, u32, u32, const hsiphash_key_t *key); +u32 hsiphash_4u32(u32, u32, u32, u32, const hsiphash_key_t *key); + +If you pass the generic hsiphash function something of a constant length, it +will constant fold at compile-time and automatically choose one of the +optimized functions. + +3. Hashtable key function usage: + +struct some_hashtable { + DECLARE_HASHTABLE(hashtable, 8); + hsiphash_key_t key; +}; + +void init_hashtable(struct some_hashtable *table) +{ + get_random_bytes(&table->key, sizeof(table->key)); +} + +static inline hlist_head *some_hashtable_bucket(struct some_hashtable *table, struct interesting_input *input) +{ + return &table->hashtable[hsiphash(input, sizeof(*input), &table->key) & (HASH_SIZE(table->hashtable) - 1)]; +} + +You may then iterate like usual over the returned hash bucket. + +4. Performance + +HalfSipHash is roughly 3 times slower than JenkinsHash. For many replacements, +this will not be a problem, as the hashtable lookup isn't the bottleneck. And +in general, this is probably a good sacrifice to make for the security and DoS +resistance of HalfSipHash. --- a/include/linux/siphash.h +++ b/include/linux/siphash.h @@ -5,7 +5,9 @@ * SipHash: a fast short-input PRF * https://131002.net/siphash/ * - * This implementation is specifically for SipHash2-4. + * This implementation is specifically for SipHash2-4 for a secure PRF + * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for + * hashtables. */

#ifndef _LINUX_SIPHASH_H @@ -87,4 +89,57 @@ static inline u64 siphash(const void *da return ___siphash_aligned(data, len, key); }

+#define HSIPHASH_ALIGNMENT __alignof__(unsigned long) +typedef struct { + unsigned long key[2]; +} hsiphash_key_t; + +u32 __hsiphash_aligned(const void *data, size_t len, + const hsiphash_key_t *key); +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS +u32 __hsiphash_unaligned(const void *data, size_t len, + const hsiphash_key_t *key); +#endif + +u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key); +u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key); +u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c, + const hsiphash_key_t *key); +u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d, + const hsiphash_key_t *key); + +static inline u32 ___hsiphash_aligned(const __le32 *data, size_t len, + const hsiphash_key_t *key) +{ + if (__builtin_constant_p(len) && len == 4) + return hsiphash_1u32(le32_to_cpu(data[0]), key); + if (__builtin_constant_p(len) && len == 8) + return hsiphash_2u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), + key); + if (__builtin_constant_p(len) && len == 12) + return hsiphash_3u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), + le32_to_cpu(data[2]), key); + if (__builtin_constant_p(len) && len == 16) + return hsiphash_4u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), + le32_to_cpu(data[2]), le32_to_cpu(data[3]), + key); + return __hsiphash_aligned(data, len, key); +} + +/** + * hsiphash - compute 32-bit hsiphash PRF value + * @data: buffer to hash + * @size: size of @data + * @key: the hsiphash key + */ +static inline u32 hsiphash(const void *data, size_t len, + const hsiphash_key_t *key) +{ +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + if (!IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT)) + return __hsiphash_unaligned(data, len, key); +#endif + return ___hsiphash_aligned(data, len, key); +} + #endif /* _LINUX_SIPHASH_H */ --- a/lib/siphash.c +++ b/lib/siphash.c @@ -5,7 +5,9 @@ * SipHash: a fast short-input PRF * https://131002.net/siphash/ * - * This implementation is specifically for SipHash2-4. + * This implementation is specifically for SipHash2-4 for a secure PRF + * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for + * hashtables. */

#include <linux/siphash.h> @@ -230,3 +232,320 @@ u64 siphash_3u32(const u32 first, const POSTAMBLE } EXPORT_SYMBOL(siphash_3u32); + +#if BITS_PER_LONG == 64 +/* Note that on 64-bit, we make HalfSipHash1-3 actually be SipHash1-3, for + * performance reasons. On 32-bit, below, we actually implement HalfSipHash1-3. + */ + +#define HSIPROUND SIPROUND +#define HPREAMBLE(len) PREAMBLE(len) +#define HPOSTAMBLE \ + v3 ^= b; \ + HSIPROUND; \ + v0 ^= b; \ + v2 ^= 0xff; \ + HSIPROUND; \ + HSIPROUND; \ + HSIPROUND; \ + return (v0 ^ v1) ^ (v2 ^ v3); + +u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key) +{ + const u8 *end = data + len - (len % sizeof(u64)); + const u8 left = len & (sizeof(u64) - 1); + u64 m; + HPREAMBLE(len) + for (; data != end; data += sizeof(u64)) { + m = le64_to_cpup(data); + v3 ^= m; + HSIPROUND; + v0 ^= m; + } +#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64 + if (left) + b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) & + bytemask_from_count(left))); +#else + switch (left) { + case 7: b |= ((u64)end[6]) << 48; + case 6: b |= ((u64)end[5]) << 40; + case 5: b |= ((u64)end[4]) << 32; + case 4: b |= le32_to_cpup(data); break; + case 3: b |= ((u64)end[2]) << 16; + case 2: b |= le16_to_cpup(data); break; + case 1: b |= end[0]; + } +#endif + HPOSTAMBLE +} +EXPORT_SYMBOL(__hsiphash_aligned); + +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS +u32 __hsiphash_unaligned(const void *data, size_t len, + const hsiphash_key_t *key) +{ + const u8 *end = data + len - (len % sizeof(u64)); + const u8 left = len & (sizeof(u64) - 1); + u64 m; + HPREAMBLE(len) + for (; data != end; data += sizeof(u64)) { + m = get_unaligned_le64(data); + v3 ^= m; + HSIPROUND; + v0 ^= m; + } +#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64 + if (left) + b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) & + bytemask_from_count(left))); +#else + switch (left) { + case 7: b |= ((u64)end[6]) << 48; + case 6: b |= ((u64)end[5]) << 40; + case 5: b |= ((u64)end[4]) << 32; + case 4: b |= get_unaligned_le32(end); break; + case 3: b |= ((u64)end[2]) << 16; + case 2: b |= get_unaligned_le16(end); break; + case 1: b |= end[0]; + } +#endif + HPOSTAMBLE +} +EXPORT_SYMBOL(__hsiphash_unaligned); +#endif + +/** + * hsiphash_1u32 - compute 64-bit hsiphash PRF value of a u32 + * @first: first u32 + * @key: the hsiphash key + */ +u32 hsiphash_1u32(const u32 first, const hsiphash_key_t *key) +{ + HPREAMBLE(4) + b |= first; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_1u32); + +/** + * hsiphash_2u32 - compute 32-bit hsiphash PRF value of 2 u32 + * @first: first u32 + * @second: second u32 + * @key: the hsiphash key + */ +u32 hsiphash_2u32(const u32 first, const u32 second, const hsiphash_key_t *key) +{ + u64 combined = (u64)second << 32 | first; + HPREAMBLE(8) + v3 ^= combined; + HSIPROUND; + v0 ^= combined; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_2u32); + +/** + * hsiphash_3u32 - compute 32-bit hsiphash PRF value of 3 u32 + * @first: first u32 + * @second: second u32 + * @third: third u32 + * @key: the hsiphash key + */ +u32 hsiphash_3u32(const u32 first, const u32 second, const u32 third, + const hsiphash_key_t *key) +{ + u64 combined = (u64)second << 32 | first; + HPREAMBLE(12) + v3 ^= combined; + HSIPROUND; + v0 ^= combined; + b |= third; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_3u32); + +/** + * hsiphash_4u32 - compute 32-bit hsiphash PRF value of 4 u32 + * @first: first u32 + * @second: second u32 + * @third: third u32 + * @forth: forth u32 + * @key: the hsiphash key + */ +u32 hsiphash_4u32(const u32 first, const u32 second, const u32 third, + const u32 forth, const hsiphash_key_t *key) +{ + u64 combined = (u64)second << 32 | first; + HPREAMBLE(16) + v3 ^= combined; + HSIPROUND; + v0 ^= combined; + combined = (u64)forth << 32 | third; + v3 ^= combined; + HSIPROUND; + v0 ^= combined; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_4u32); +#else +#define HSIPROUND \ + do { \ + v0 += v1; v1 = rol32(v1, 5); v1 ^= v0; v0 = rol32(v0, 16); \ + v2 += v3; v3 = rol32(v3, 8); v3 ^= v2; \ + v0 += v3; v3 = rol32(v3, 7); v3 ^= v0; \ + v2 += v1; v1 = rol32(v1, 13); v1 ^= v2; v2 = rol32(v2, 16); \ + } while (0) + +#define HPREAMBLE(len) \ + u32 v0 = 0; \ + u32 v1 = 0; \ + u32 v2 = 0x6c796765U; \ + u32 v3 = 0x74656462U; \ + u32 b = ((u32)(len)) << 24; \ + v3 ^= key->key[1]; \ + v2 ^= key->key[0]; \ + v1 ^= key->key[1]; \ + v0 ^= key->key[0]; + +#define HPOSTAMBLE \ + v3 ^= b; \ + HSIPROUND; \ + v0 ^= b; \ + v2 ^= 0xff; \ + HSIPROUND; \ + HSIPROUND; \ + HSIPROUND; \ + return v1 ^ v3; + +u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key) +{ + const u8 *end = data + len - (len % sizeof(u32)); + const u8 left = len & (sizeof(u32) - 1); + u32 m; + HPREAMBLE(len) + for (; data != end; data += sizeof(u32)) { + m = le32_to_cpup(data); + v3 ^= m; + HSIPROUND; + v0 ^= m; + } + switch (left) { + case 3: b |= ((u32)end[2]) << 16; + case 2: b |= le16_to_cpup(data); break; + case 1: b |= end[0]; + } + HPOSTAMBLE +} +EXPORT_SYMBOL(__hsiphash_aligned); + +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS +u32 __hsiphash_unaligned(const void *data, size_t len, + const hsiphash_key_t *key) +{ + const u8 *end = data + len - (len % sizeof(u32)); + const u8 left = len & (sizeof(u32) - 1); + u32 m; + HPREAMBLE(len) + for (; data != end; data += sizeof(u32)) { + m = get_unaligned_le32(data); + v3 ^= m; + HSIPROUND; + v0 ^= m; + } + switch (left) { + case 3: b |= ((u32)end[2]) << 16; + case 2: b |= get_unaligned_le16(end); break; + case 1: b |= end[0]; + } + HPOSTAMBLE +} +EXPORT_SYMBOL(__hsiphash_unaligned); +#endif + +/** + * hsiphash_1u32 - compute 32-bit hsiphash PRF value of a u32 + * @first: first u32 + * @key: the hsiphash key + */ +u32 hsiphash_1u32(const u32 first, const hsiphash_key_t *key) +{ + HPREAMBLE(4) + v3 ^= first; + HSIPROUND; + v0 ^= first; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_1u32); + +/** + * hsiphash_2u32 - compute 32-bit hsiphash PRF value of 2 u32 + * @first: first u32 + * @second: second u32 + * @key: the hsiphash key + */ +u32 hsiphash_2u32(const u32 first, const u32 second, const hsiphash_key_t *key) +{ + HPREAMBLE(8) + v3 ^= first; + HSIPROUND; + v0 ^= first; + v3 ^= second; + HSIPROUND; + v0 ^= second; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_2u32); + +/** + * hsiphash_3u32 - compute 32-bit hsiphash PRF value of 3 u32 + * @first: first u32 + * @second: second u32 + * @third: third u32 + * @key: the hsiphash key + */ +u32 hsiphash_3u32(const u32 first, const u32 second, const u32 third, + const hsiphash_key_t *key) +{ + HPREAMBLE(12) + v3 ^= first; + HSIPROUND; + v0 ^= first; + v3 ^= second; + HSIPROUND; + v0 ^= second; + v3 ^= third; + HSIPROUND; + v0 ^= third; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_3u32); + +/** + * hsiphash_4u32 - compute 32-bit hsiphash PRF value of 4 u32 + * @first: first u32 + * @second: second u32 + * @third: third u32 + * @forth: forth u32 + * @key: the hsiphash key + */ +u32 hsiphash_4u32(const u32 first, const u32 second, const u32 third, + const u32 forth, const hsiphash_key_t *key) +{ + HPREAMBLE(16) + v3 ^= first; + HSIPROUND; + v0 ^= first; + v3 ^= second; + HSIPROUND; + v0 ^= second; + v3 ^= third; + HSIPROUND; + v0 ^= third; + v3 ^= forth; + HSIPROUND; + v0 ^= forth; + HPOSTAMBLE +} +EXPORT_SYMBOL(hsiphash_4u32); +#endif --- a/lib/test_siphash.c +++ b/lib/test_siphash.c @@ -7,7 +7,9 @@ * SipHash: a fast short-input PRF * https://131002.net/siphash/ * - * This implementation is specifically for SipHash2-4. + * This implementation is specifically for SipHash2-4 for a secure PRF + * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for + * hashtables. */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -18,8 +20,8 @@ #include <linux/errno.h> #include <linux/module.h>

-/* Test vectors taken from official reference source available at: - * https://131002.net/siphash/siphash24.c +/* Test vectors taken from reference source available at: + * https://github.com/veorq/SipHash */

static const siphash_key_t test_key_siphash = @@ -50,6 +52,64 @@ static const u64 test_vectors_siphash[64 0x958a324ceb064572ULL };

+#if BITS_PER_LONG == 64 +static const hsiphash_key_t test_key_hsiphash = + {{ 0x0706050403020100ULL, 0x0f0e0d0c0b0a0908ULL }}; + +static const u32 test_vectors_hsiphash[64] = { + 0x050fc4dcU, 0x7d57ca93U, 0x4dc7d44dU, + 0xe7ddf7fbU, 0x88d38328U, 0x49533b67U, + 0xc59f22a7U, 0x9bb11140U, 0x8d299a8eU, + 0x6c063de4U, 0x92ff097fU, 0xf94dc352U, + 0x57b4d9a2U, 0x1229ffa7U, 0xc0f95d34U, + 0x2a519956U, 0x7d908b66U, 0x63dbd80cU, + 0xb473e63eU, 0x8d297d1cU, 0xa6cce040U, + 0x2b45f844U, 0xa320872eU, 0xdae6c123U, + 0x67349c8cU, 0x705b0979U, 0xca9913a5U, + 0x4ade3b35U, 0xef6cd00dU, 0x4ab1e1f4U, + 0x43c5e663U, 0x8c21d1bcU, 0x16a7b60dU, + 0x7a8ff9bfU, 0x1f2a753eU, 0xbf186b91U, + 0xada26206U, 0xa3c33057U, 0xae3a36a1U, + 0x7b108392U, 0x99e41531U, 0x3f1ad944U, + 0xc8138825U, 0xc28949a6U, 0xfaf8876bU, + 0x9f042196U, 0x68b1d623U, 0x8b5114fdU, + 0xdf074c46U, 0x12cc86b3U, 0x0a52098fU, + 0x9d292f9aU, 0xa2f41f12U, 0x43a71ed0U, + 0x73f0bce6U, 0x70a7e980U, 0x243c6d75U, + 0xfdb71513U, 0xa67d8a08U, 0xb7e8f148U, + 0xf7a644eeU, 0x0f1837f2U, 0x4b6694e0U, + 0xb7bbb3a8U +}; +#else +static const hsiphash_key_t test_key_hsiphash = + {{ 0x03020100U, 0x07060504U }}; + +static const u32 test_vectors_hsiphash[64] = { + 0x5814c896U, 0xe7e864caU, 0xbc4b0e30U, + 0x01539939U, 0x7e059ea6U, 0x88e3d89bU, + 0xa0080b65U, 0x9d38d9d6U, 0x577999b1U, + 0xc839caedU, 0xe4fa32cfU, 0x959246eeU, + 0x6b28096cU, 0x66dd9cd6U, 0x16658a7cU, + 0xd0257b04U, 0x8b31d501U, 0x2b1cd04bU, + 0x06712339U, 0x522aca67U, 0x911bb605U, + 0x90a65f0eU, 0xf826ef7bU, 0x62512debU, + 0x57150ad7U, 0x5d473507U, 0x1ec47442U, + 0xab64afd3U, 0x0a4100d0U, 0x6d2ce652U, + 0x2331b6a3U, 0x08d8791aU, 0xbc6dda8dU, + 0xe0f6c934U, 0xb0652033U, 0x9b9851ccU, + 0x7c46fb7fU, 0x732ba8cbU, 0xf142997aU, + 0xfcc9aa1bU, 0x05327eb2U, 0xe110131cU, + 0xf9e5e7c0U, 0xa7d708a6U, 0x11795ab1U, + 0x65671619U, 0x9f5fff91U, 0xd89c5267U, + 0x007783ebU, 0x95766243U, 0xab639262U, + 0x9c7e1390U, 0xc368dda6U, 0x38ddc455U, + 0xfa13d379U, 0x979ea4e8U, 0x53ecd77eU, + 0x2ee80657U, 0x33dbb66aU, 0xae3f0577U, + 0x88b4c4ccU, 0x3e7f480bU, 0x74c1ebf8U, + 0x87178304U +}; +#endif + static int __init siphash_test_init(void) { u8 in[64] __aligned(SIPHASH_ALIGNMENT); @@ -70,6 +130,16 @@ static int __init siphash_test_init(void pr_info("siphash self-test unaligned %u: FAIL\n", i + 1); ret = -EINVAL; } + if (hsiphash(in, i, &test_key_hsiphash) != + test_vectors_hsiphash[i]) { + pr_info("hsiphash self-test aligned %u: FAIL\n", i + 1); + ret = -EINVAL; + } + if (hsiphash(in_unaligned + 1, i, &test_key_hsiphash) != + test_vectors_hsiphash[i]) { + pr_info("hsiphash self-test unaligned %u: FAIL\n", i + 1); + ret = -EINVAL; + } } if (siphash_1u64(0x0706050403020100ULL, &test_key_siphash) != test_vectors_siphash[8]) { @@ -115,6 +185,28 @@ static int __init siphash_test_init(void pr_info("siphash self-test 4u32: FAIL\n"); ret = -EINVAL; } + if (hsiphash_1u32(0x03020100U, &test_key_hsiphash) != + test_vectors_hsiphash[4]) { + pr_info("hsiphash self-test 1u32: FAIL\n"); + ret = -EINVAL; + } + if (hsiphash_2u32(0x03020100U, 0x07060504U, &test_key_hsiphash) != + test_vectors_hsiphash[8]) { + pr_info("hsiphash self-test 2u32: FAIL\n"); + ret = -EINVAL; + } + if (hsiphash_3u32(0x03020100U, 0x07060504U, + 0x0b0a0908U, &test_key_hsiphash) != + test_vectors_hsiphash[12]) { + pr_info("hsiphash self-test 3u32: FAIL\n"); + ret = -EINVAL; + } + if (hsiphash_4u32(0x03020100U, 0x07060504U, + 0x0b0a0908U, 0x0f0e0d0cU, &test_key_hsiphash) != + test_vectors_hsiphash[16]) { + pr_info("hsiphash self-test 4u32: FAIL\n"); + ret = -EINVAL; + } if (!ret) pr_info("self-tests: pass\n"); return ret;

3.16.73-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Ben Hutchings ben@decadent.org.uk

Denis Andzakovic discovered a potential use-after-free in older kernel versions, using syzkaller. tcp_write_queue_purge() frees all skbs in the TCP write queue and can leave sk->sk_send_head pointing to freed memory. tcp_disconnect() clears that pointer after calling tcp_write_queue_purge(), but tcp_connect() does not. It is (surprisingly) possible to add to the write queue between disconnection and reconnection, so this needs to be done in both places.

This bug was introduced by backports of commit 7f582b248d0a ("tcp: purge write queue in tcp_connect_init()") and does not exist upstream because of earlier changes in commit 75c119afe14f ("tcp: implement rb-tree based retransmit queue"). The latter is a major change that's not suitable for stable.

Reported-by: Denis Andzakovic denis.andzakovic@pulsesecurity.co.nz Bisected-by: Salvatore Bonaccorso carnil@debian.org Fixes: 7f582b248d0a ("tcp: purge write queue in tcp_connect_init()") Cc: stable@vger.kernel.org # before 4.15 Cc: Eric Dumazet edumazet@google.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- include/net/tcp.h | 3 +++ 1 file changed, 3 insertions(+)

--- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1352,6 +1352,8 @@ struct tcp_fastopen_context { struct rcu_head rcu; };

+static inline void tcp_init_send_head(struct sock *sk); + /* write queue abstraction */ static inline void tcp_write_queue_purge(struct sock *sk) { @@ -1359,6 +1361,7 @@ static inline void tcp_write_queue_purge

while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) sk_wmem_free_skb(sk, skb); + tcp_init_send_head(sk); sk_mem_reclaim(sk); tcp_clear_all_retrans_hints(tcp_sk(sk)); }