Revision 321027c1fe77f892f4ea07846aeae08cefbbb290 authored by Peter Zijlstra on 11 January 2017, 20:09:50 UTC, committed by Ingo Molnar on 14 January 2017, 09:56:11 UTC
Di Shen reported a race between two concurrent sys_perf_event_open() calls where both try and move the same pre-existing software group into a hardware context. The problem is exactly that described in commit: f63a8daa5812 ("perf: Fix event->ctx locking") ... where, while we wait for a ctx->mutex acquisition, the event->ctx relation can have changed under us. That very same commit failed to recognise sys_perf_event_context() as an external access vector to the events and thereby didn't apply the established locking rules correctly. So while one sys_perf_event_open() call is stuck waiting on mutex_lock_double(), the other (which owns said locks) moves the group about. So by the time the former sys_perf_event_open() acquires the locks, the context we've acquired is stale (and possibly dead). Apply the established locking rules as per perf_event_ctx_lock_nested() to the mutex_lock_double() for the 'move_group' case. This obviously means we need to validate state after we acquire the locks. Reported-by: Di Shen (Keen Lab) Tested-by: John Dias <joaodias@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Min Chong <mchong@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: f63a8daa5812 ("perf: Fix event->ctx locking") Link: http://lkml.kernel.org/r/20170106131444.GZ3174@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 63cae12
tea.c
/*
* Cryptographic API.
*
* TEA, XTEA, and XETA crypto alogrithms
*
* The TEA and Xtended TEA algorithms were developed by David Wheeler
* and Roger Needham at the Computer Laboratory of Cambridge University.
*
* Due to the order of evaluation in XTEA many people have incorrectly
* implemented it. XETA (XTEA in the wrong order), exists for
* compatibility with these implementations.
*
* Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <asm/byteorder.h>
#include <linux/crypto.h>
#include <linux/types.h>
#define TEA_KEY_SIZE 16
#define TEA_BLOCK_SIZE 8
#define TEA_ROUNDS 32
#define TEA_DELTA 0x9e3779b9
#define XTEA_KEY_SIZE 16
#define XTEA_BLOCK_SIZE 8
#define XTEA_ROUNDS 32
#define XTEA_DELTA 0x9e3779b9
struct tea_ctx {
u32 KEY[4];
};
struct xtea_ctx {
u32 KEY[4];
};
static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *key = (const __le32 *)in_key;
ctx->KEY[0] = le32_to_cpu(key[0]);
ctx->KEY[1] = le32_to_cpu(key[1]);
ctx->KEY[2] = le32_to_cpu(key[2]);
ctx->KEY[3] = le32_to_cpu(key[3]);
return 0;
}
static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
u32 y, z, n, sum = 0;
u32 k0, k1, k2, k3;
struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *in = (const __le32 *)src;
__le32 *out = (__le32 *)dst;
y = le32_to_cpu(in[0]);
z = le32_to_cpu(in[1]);
k0 = ctx->KEY[0];
k1 = ctx->KEY[1];
k2 = ctx->KEY[2];
k3 = ctx->KEY[3];
n = TEA_ROUNDS;
while (n-- > 0) {
sum += TEA_DELTA;
y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
}
out[0] = cpu_to_le32(y);
out[1] = cpu_to_le32(z);
}
static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
u32 y, z, n, sum;
u32 k0, k1, k2, k3;
struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *in = (const __le32 *)src;
__le32 *out = (__le32 *)dst;
y = le32_to_cpu(in[0]);
z = le32_to_cpu(in[1]);
k0 = ctx->KEY[0];
k1 = ctx->KEY[1];
k2 = ctx->KEY[2];
k3 = ctx->KEY[3];
sum = TEA_DELTA << 5;
n = TEA_ROUNDS;
while (n-- > 0) {
z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
sum -= TEA_DELTA;
}
out[0] = cpu_to_le32(y);
out[1] = cpu_to_le32(z);
}
static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *key = (const __le32 *)in_key;
ctx->KEY[0] = le32_to_cpu(key[0]);
ctx->KEY[1] = le32_to_cpu(key[1]);
ctx->KEY[2] = le32_to_cpu(key[2]);
ctx->KEY[3] = le32_to_cpu(key[3]);
return 0;
}
static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
u32 y, z, sum = 0;
u32 limit = XTEA_DELTA * XTEA_ROUNDS;
struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *in = (const __le32 *)src;
__le32 *out = (__le32 *)dst;
y = le32_to_cpu(in[0]);
z = le32_to_cpu(in[1]);
while (sum != limit) {
y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
sum += XTEA_DELTA;
z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
}
out[0] = cpu_to_le32(y);
out[1] = cpu_to_le32(z);
}
static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
u32 y, z, sum;
struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *in = (const __le32 *)src;
__le32 *out = (__le32 *)dst;
y = le32_to_cpu(in[0]);
z = le32_to_cpu(in[1]);
sum = XTEA_DELTA * XTEA_ROUNDS;
while (sum) {
z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
sum -= XTEA_DELTA;
y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
}
out[0] = cpu_to_le32(y);
out[1] = cpu_to_le32(z);
}
static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
u32 y, z, sum = 0;
u32 limit = XTEA_DELTA * XTEA_ROUNDS;
struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *in = (const __le32 *)src;
__le32 *out = (__le32 *)dst;
y = le32_to_cpu(in[0]);
z = le32_to_cpu(in[1]);
while (sum != limit) {
y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
sum += XTEA_DELTA;
z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
}
out[0] = cpu_to_le32(y);
out[1] = cpu_to_le32(z);
}
static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
u32 y, z, sum;
struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *in = (const __le32 *)src;
__le32 *out = (__le32 *)dst;
y = le32_to_cpu(in[0]);
z = le32_to_cpu(in[1]);
sum = XTEA_DELTA * XTEA_ROUNDS;
while (sum) {
z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
sum -= XTEA_DELTA;
y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
}
out[0] = cpu_to_le32(y);
out[1] = cpu_to_le32(z);
}
static struct crypto_alg tea_algs[3] = { {
.cra_name = "tea",
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = TEA_BLOCK_SIZE,
.cra_ctxsize = sizeof (struct tea_ctx),
.cra_alignmask = 3,
.cra_module = THIS_MODULE,
.cra_u = { .cipher = {
.cia_min_keysize = TEA_KEY_SIZE,
.cia_max_keysize = TEA_KEY_SIZE,
.cia_setkey = tea_setkey,
.cia_encrypt = tea_encrypt,
.cia_decrypt = tea_decrypt } }
}, {
.cra_name = "xtea",
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = XTEA_BLOCK_SIZE,
.cra_ctxsize = sizeof (struct xtea_ctx),
.cra_alignmask = 3,
.cra_module = THIS_MODULE,
.cra_u = { .cipher = {
.cia_min_keysize = XTEA_KEY_SIZE,
.cia_max_keysize = XTEA_KEY_SIZE,
.cia_setkey = xtea_setkey,
.cia_encrypt = xtea_encrypt,
.cia_decrypt = xtea_decrypt } }
}, {
.cra_name = "xeta",
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = XTEA_BLOCK_SIZE,
.cra_ctxsize = sizeof (struct xtea_ctx),
.cra_alignmask = 3,
.cra_module = THIS_MODULE,
.cra_u = { .cipher = {
.cia_min_keysize = XTEA_KEY_SIZE,
.cia_max_keysize = XTEA_KEY_SIZE,
.cia_setkey = xtea_setkey,
.cia_encrypt = xeta_encrypt,
.cia_decrypt = xeta_decrypt } }
} };
static int __init tea_mod_init(void)
{
return crypto_register_algs(tea_algs, ARRAY_SIZE(tea_algs));
}
static void __exit tea_mod_fini(void)
{
crypto_unregister_algs(tea_algs, ARRAY_SIZE(tea_algs));
}
MODULE_ALIAS_CRYPTO("tea");
MODULE_ALIAS_CRYPTO("xtea");
MODULE_ALIAS_CRYPTO("xeta");
module_init(tea_mod_init);
module_exit(tea_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");
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