Revision ec3937107ab43f3e8b2bc9dad95710043c462ff7 authored by Baoquan He on 04 April 2019, 02:03:13 UTC, committed by Borislav Petkov on 18 April 2019, 08:42:58 UTC
kernel_randomize_memory() uses __PHYSICAL_MASK_SHIFT to calculate the maximum amount of system RAM supported. The size of the direct mapping section is obtained from the smaller one of the below two values: (actual system RAM size + padding size) vs (max system RAM size supported) This calculation is wrong since commit b83ce5ee9147 ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"). In it, __PHYSICAL_MASK_SHIFT was changed to be 52, regardless of whether the kernel is using 4-level or 5-level page tables. Thus, it will always use 4 PB as the maximum amount of system RAM, even in 4-level paging mode where it should actually be 64 TB. Thus, the size of the direct mapping section will always be the sum of the actual system RAM size plus the padding size. Even when the amount of system RAM is 64 TB, the following layout will still be used. Obviously KALSR will be weakened significantly. |____|_______actual RAM_______|_padding_|______the rest_______| 0 64TB ~120TB Instead, it should be like this: |____|_______actual RAM_______|_________the rest______________| 0 64TB ~120TB The size of padding region is controlled by CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING, which is 10 TB by default. The above issue only exists when CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING is set to a non-zero value, which is the case when CONFIG_MEMORY_HOTPLUG is enabled. Otherwise, using __PHYSICAL_MASK_SHIFT doesn't affect KASLR. Fix it by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS. [ bp: Massage commit message. ] Fixes: b83ce5ee9147 ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52") Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Thomas Garnier <thgarnie@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: frank.ramsay@hpe.com Cc: herbert@gondor.apana.org.au Cc: kirill@shutemov.name Cc: mike.travis@hpe.com Cc: thgarnie@google.com Cc: x86-ml <x86@kernel.org> Cc: yamada.masahiro@socionext.com Link: https://lkml.kernel.org/r/20190417083536.GE7065@MiWiFi-R3L-srv
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md4.c
/*
* Cryptographic API.
*
* MD4 Message Digest Algorithm (RFC1320).
*
* Implementation derived from Andrew Tridgell and Steve French's
* CIFS MD4 implementation, and the cryptoapi implementation
* originally based on the public domain implementation written
* by Colin Plumb in 1993.
*
* Copyright (c) Andrew Tridgell 1997-1998.
* Modified by Steve French (sfrench@us.ibm.com) 2002
* Copyright (c) Cryptoapi developers.
* Copyright (c) 2002 David S. Miller (davem@redhat.com)
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
*
* 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 <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/types.h>
#include <asm/byteorder.h>
#define MD4_DIGEST_SIZE 16
#define MD4_HMAC_BLOCK_SIZE 64
#define MD4_BLOCK_WORDS 16
#define MD4_HASH_WORDS 4
struct md4_ctx {
u32 hash[MD4_HASH_WORDS];
u32 block[MD4_BLOCK_WORDS];
u64 byte_count;
};
static inline u32 lshift(u32 x, unsigned int s)
{
x &= 0xFFFFFFFF;
return ((x << s) & 0xFFFFFFFF) | (x >> (32 - s));
}
static inline u32 F(u32 x, u32 y, u32 z)
{
return (x & y) | ((~x) & z);
}
static inline u32 G(u32 x, u32 y, u32 z)
{
return (x & y) | (x & z) | (y & z);
}
static inline u32 H(u32 x, u32 y, u32 z)
{
return x ^ y ^ z;
}
#define ROUND1(a,b,c,d,k,s) (a = lshift(a + F(b,c,d) + k, s))
#define ROUND2(a,b,c,d,k,s) (a = lshift(a + G(b,c,d) + k + (u32)0x5A827999,s))
#define ROUND3(a,b,c,d,k,s) (a = lshift(a + H(b,c,d) + k + (u32)0x6ED9EBA1,s))
static void md4_transform(u32 *hash, u32 const *in)
{
u32 a, b, c, d;
a = hash[0];
b = hash[1];
c = hash[2];
d = hash[3];
ROUND1(a, b, c, d, in[0], 3);
ROUND1(d, a, b, c, in[1], 7);
ROUND1(c, d, a, b, in[2], 11);
ROUND1(b, c, d, a, in[3], 19);
ROUND1(a, b, c, d, in[4], 3);
ROUND1(d, a, b, c, in[5], 7);
ROUND1(c, d, a, b, in[6], 11);
ROUND1(b, c, d, a, in[7], 19);
ROUND1(a, b, c, d, in[8], 3);
ROUND1(d, a, b, c, in[9], 7);
ROUND1(c, d, a, b, in[10], 11);
ROUND1(b, c, d, a, in[11], 19);
ROUND1(a, b, c, d, in[12], 3);
ROUND1(d, a, b, c, in[13], 7);
ROUND1(c, d, a, b, in[14], 11);
ROUND1(b, c, d, a, in[15], 19);
ROUND2(a, b, c, d,in[ 0], 3);
ROUND2(d, a, b, c, in[4], 5);
ROUND2(c, d, a, b, in[8], 9);
ROUND2(b, c, d, a, in[12], 13);
ROUND2(a, b, c, d, in[1], 3);
ROUND2(d, a, b, c, in[5], 5);
ROUND2(c, d, a, b, in[9], 9);
ROUND2(b, c, d, a, in[13], 13);
ROUND2(a, b, c, d, in[2], 3);
ROUND2(d, a, b, c, in[6], 5);
ROUND2(c, d, a, b, in[10], 9);
ROUND2(b, c, d, a, in[14], 13);
ROUND2(a, b, c, d, in[3], 3);
ROUND2(d, a, b, c, in[7], 5);
ROUND2(c, d, a, b, in[11], 9);
ROUND2(b, c, d, a, in[15], 13);
ROUND3(a, b, c, d,in[ 0], 3);
ROUND3(d, a, b, c, in[8], 9);
ROUND3(c, d, a, b, in[4], 11);
ROUND3(b, c, d, a, in[12], 15);
ROUND3(a, b, c, d, in[2], 3);
ROUND3(d, a, b, c, in[10], 9);
ROUND3(c, d, a, b, in[6], 11);
ROUND3(b, c, d, a, in[14], 15);
ROUND3(a, b, c, d, in[1], 3);
ROUND3(d, a, b, c, in[9], 9);
ROUND3(c, d, a, b, in[5], 11);
ROUND3(b, c, d, a, in[13], 15);
ROUND3(a, b, c, d, in[3], 3);
ROUND3(d, a, b, c, in[11], 9);
ROUND3(c, d, a, b, in[7], 11);
ROUND3(b, c, d, a, in[15], 15);
hash[0] += a;
hash[1] += b;
hash[2] += c;
hash[3] += d;
}
static inline void md4_transform_helper(struct md4_ctx *ctx)
{
le32_to_cpu_array(ctx->block, ARRAY_SIZE(ctx->block));
md4_transform(ctx->hash, ctx->block);
}
static int md4_init(struct shash_desc *desc)
{
struct md4_ctx *mctx = shash_desc_ctx(desc);
mctx->hash[0] = 0x67452301;
mctx->hash[1] = 0xefcdab89;
mctx->hash[2] = 0x98badcfe;
mctx->hash[3] = 0x10325476;
mctx->byte_count = 0;
return 0;
}
static int md4_update(struct shash_desc *desc, const u8 *data, unsigned int len)
{
struct md4_ctx *mctx = shash_desc_ctx(desc);
const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
mctx->byte_count += len;
if (avail > len) {
memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
data, len);
return 0;
}
memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
data, avail);
md4_transform_helper(mctx);
data += avail;
len -= avail;
while (len >= sizeof(mctx->block)) {
memcpy(mctx->block, data, sizeof(mctx->block));
md4_transform_helper(mctx);
data += sizeof(mctx->block);
len -= sizeof(mctx->block);
}
memcpy(mctx->block, data, len);
return 0;
}
static int md4_final(struct shash_desc *desc, u8 *out)
{
struct md4_ctx *mctx = shash_desc_ctx(desc);
const unsigned int offset = mctx->byte_count & 0x3f;
char *p = (char *)mctx->block + offset;
int padding = 56 - (offset + 1);
*p++ = 0x80;
if (padding < 0) {
memset(p, 0x00, padding + sizeof (u64));
md4_transform_helper(mctx);
p = (char *)mctx->block;
padding = 56;
}
memset(p, 0, padding);
mctx->block[14] = mctx->byte_count << 3;
mctx->block[15] = mctx->byte_count >> 29;
le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
sizeof(u64)) / sizeof(u32));
md4_transform(mctx->hash, mctx->block);
cpu_to_le32_array(mctx->hash, ARRAY_SIZE(mctx->hash));
memcpy(out, mctx->hash, sizeof(mctx->hash));
memset(mctx, 0, sizeof(*mctx));
return 0;
}
static struct shash_alg alg = {
.digestsize = MD4_DIGEST_SIZE,
.init = md4_init,
.update = md4_update,
.final = md4_final,
.descsize = sizeof(struct md4_ctx),
.base = {
.cra_name = "md4",
.cra_blocksize = MD4_HMAC_BLOCK_SIZE,
.cra_module = THIS_MODULE,
}
};
static int __init md4_mod_init(void)
{
return crypto_register_shash(&alg);
}
static void __exit md4_mod_fini(void)
{
crypto_unregister_shash(&alg);
}
module_init(md4_mod_init);
module_exit(md4_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MD4 Message Digest Algorithm");
MODULE_ALIAS_CRYPTO("md4");
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