Revision a318f12ed8843cfac53198390c74a565c632f417 authored by Kees Cook on 16 July 2019, 23:30:21 UTC, committed by Linus Torvalds on 17 July 2019, 02:23:24 UTC
Andreas Christoforou reported:

  UBSAN: Undefined behaviour in ipc/mqueue.c:414:49 signed integer overflow:
  9 * 2305843009213693951 cannot be represented in type 'long int'
  ...
  Call Trace:
    mqueue_evict_inode+0x8e7/0xa10 ipc/mqueue.c:414
    evict+0x472/0x8c0 fs/inode.c:558
    iput_final fs/inode.c:1547 [inline]
    iput+0x51d/0x8c0 fs/inode.c:1573
    mqueue_get_inode+0x8eb/0x1070 ipc/mqueue.c:320
    mqueue_create_attr+0x198/0x440 ipc/mqueue.c:459
    vfs_mkobj+0x39e/0x580 fs/namei.c:2892
    prepare_open ipc/mqueue.c:731 [inline]
    do_mq_open+0x6da/0x8e0 ipc/mqueue.c:771

Which could be triggered by:

        struct mq_attr attr = {
                .mq_flags = 0,
                .mq_maxmsg = 9,
                .mq_msgsize = 0x1fffffffffffffff,
                .mq_curmsgs = 0,
        };

        if (mq_open("/testing", 0x40, 3, &attr) == (mqd_t) -1)
                perror("mq_open");

mqueue_get_inode() was correctly rejecting the giant mq_msgsize, and
preparing to return -EINVAL.  During the cleanup, it calls
mqueue_evict_inode() which performed resource usage tracking math for
updating "user", before checking if there was a valid "user" at all
(which would indicate that the calculations would be sane).  Instead,
delay this check to after seeing a valid "user".

The overflow was real, but the results went unused, so while the flaw is
harmless, it's noisy for kernel fuzzers, so just fix it by moving the
calculation under the non-NULL "user" where it actually gets used.

Link: http://lkml.kernel.org/r/201906072207.ECB65450@keescook
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Andreas Christoforou <andreaschristofo@gmail.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 6b15f67
Raw File
rmd256.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * RIPEMD-256 - RACE Integrity Primitives Evaluation Message Digest.
 *
 * Based on the reference implementation by Antoon Bosselaers, ESAT-COSIC
 *
 * Copyright (c) 2008 Adrian-Ken Rueegsegger <ken@codelabs.ch>
 */
#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <asm/byteorder.h>

#include "ripemd.h"

struct rmd256_ctx {
	u64 byte_count;
	u32 state[8];
	__le32 buffer[16];
};

#define K1  RMD_K1
#define K2  RMD_K2
#define K3  RMD_K3
#define K4  RMD_K4
#define KK1 RMD_K6
#define KK2 RMD_K7
#define KK3 RMD_K8
#define KK4 RMD_K1

#define F1(x, y, z) (x ^ y ^ z)		/* XOR */
#define F2(x, y, z) (z ^ (x & (y ^ z)))	/* x ? y : z */
#define F3(x, y, z) ((x | ~y) ^ z)
#define F4(x, y, z) (y ^ (z & (x ^ y)))	/* z ? x : y */

#define ROUND(a, b, c, d, f, k, x, s)  { \
	(a) += f((b), (c), (d)) + le32_to_cpup(&(x)) + (k); \
	(a) = rol32((a), (s)); \
}

static void rmd256_transform(u32 *state, const __le32 *in)
{
	u32 aa, bb, cc, dd, aaa, bbb, ccc, ddd;

	/* Initialize left lane */
	aa = state[0];
	bb = state[1];
	cc = state[2];
	dd = state[3];

	/* Initialize right lane */
	aaa = state[4];
	bbb = state[5];
	ccc = state[6];
	ddd = state[7];

	/* round 1: left lane */
	ROUND(aa, bb, cc, dd, F1, K1, in[0],  11);
	ROUND(dd, aa, bb, cc, F1, K1, in[1],  14);
	ROUND(cc, dd, aa, bb, F1, K1, in[2],  15);
	ROUND(bb, cc, dd, aa, F1, K1, in[3],  12);
	ROUND(aa, bb, cc, dd, F1, K1, in[4],   5);
	ROUND(dd, aa, bb, cc, F1, K1, in[5],   8);
	ROUND(cc, dd, aa, bb, F1, K1, in[6],   7);
	ROUND(bb, cc, dd, aa, F1, K1, in[7],   9);
	ROUND(aa, bb, cc, dd, F1, K1, in[8],  11);
	ROUND(dd, aa, bb, cc, F1, K1, in[9],  13);
	ROUND(cc, dd, aa, bb, F1, K1, in[10], 14);
	ROUND(bb, cc, dd, aa, F1, K1, in[11], 15);
	ROUND(aa, bb, cc, dd, F1, K1, in[12],  6);
	ROUND(dd, aa, bb, cc, F1, K1, in[13],  7);
	ROUND(cc, dd, aa, bb, F1, K1, in[14],  9);
	ROUND(bb, cc, dd, aa, F1, K1, in[15],  8);

	/* round 1: right lane */
	ROUND(aaa, bbb, ccc, ddd, F4, KK1, in[5],   8);
	ROUND(ddd, aaa, bbb, ccc, F4, KK1, in[14],  9);
	ROUND(ccc, ddd, aaa, bbb, F4, KK1, in[7],   9);
	ROUND(bbb, ccc, ddd, aaa, F4, KK1, in[0],  11);
	ROUND(aaa, bbb, ccc, ddd, F4, KK1, in[9],  13);
	ROUND(ddd, aaa, bbb, ccc, F4, KK1, in[2],  15);
	ROUND(ccc, ddd, aaa, bbb, F4, KK1, in[11], 15);
	ROUND(bbb, ccc, ddd, aaa, F4, KK1, in[4],   5);
	ROUND(aaa, bbb, ccc, ddd, F4, KK1, in[13],  7);
	ROUND(ddd, aaa, bbb, ccc, F4, KK1, in[6],   7);
	ROUND(ccc, ddd, aaa, bbb, F4, KK1, in[15],  8);
	ROUND(bbb, ccc, ddd, aaa, F4, KK1, in[8],  11);
	ROUND(aaa, bbb, ccc, ddd, F4, KK1, in[1],  14);
	ROUND(ddd, aaa, bbb, ccc, F4, KK1, in[10], 14);
	ROUND(ccc, ddd, aaa, bbb, F4, KK1, in[3],  12);
	ROUND(bbb, ccc, ddd, aaa, F4, KK1, in[12],  6);

	/* Swap contents of "a" registers */
	swap(aa, aaa);

	/* round 2: left lane */
	ROUND(aa, bb, cc, dd, F2, K2, in[7],   7);
	ROUND(dd, aa, bb, cc, F2, K2, in[4],   6);
	ROUND(cc, dd, aa, bb, F2, K2, in[13],  8);
	ROUND(bb, cc, dd, aa, F2, K2, in[1],  13);
	ROUND(aa, bb, cc, dd, F2, K2, in[10], 11);
	ROUND(dd, aa, bb, cc, F2, K2, in[6],   9);
	ROUND(cc, dd, aa, bb, F2, K2, in[15],  7);
	ROUND(bb, cc, dd, aa, F2, K2, in[3],  15);
	ROUND(aa, bb, cc, dd, F2, K2, in[12],  7);
	ROUND(dd, aa, bb, cc, F2, K2, in[0],  12);
	ROUND(cc, dd, aa, bb, F2, K2, in[9],  15);
	ROUND(bb, cc, dd, aa, F2, K2, in[5],   9);
	ROUND(aa, bb, cc, dd, F2, K2, in[2],  11);
	ROUND(dd, aa, bb, cc, F2, K2, in[14],  7);
	ROUND(cc, dd, aa, bb, F2, K2, in[11], 13);
	ROUND(bb, cc, dd, aa, F2, K2, in[8],  12);

	/* round 2: right lane */
	ROUND(aaa, bbb, ccc, ddd, F3, KK2, in[6],   9);
	ROUND(ddd, aaa, bbb, ccc, F3, KK2, in[11], 13);
	ROUND(ccc, ddd, aaa, bbb, F3, KK2, in[3],  15);
	ROUND(bbb, ccc, ddd, aaa, F3, KK2, in[7],   7);
	ROUND(aaa, bbb, ccc, ddd, F3, KK2, in[0],  12);
	ROUND(ddd, aaa, bbb, ccc, F3, KK2, in[13],  8);
	ROUND(ccc, ddd, aaa, bbb, F3, KK2, in[5],   9);
	ROUND(bbb, ccc, ddd, aaa, F3, KK2, in[10], 11);
	ROUND(aaa, bbb, ccc, ddd, F3, KK2, in[14],  7);
	ROUND(ddd, aaa, bbb, ccc, F3, KK2, in[15],  7);
	ROUND(ccc, ddd, aaa, bbb, F3, KK2, in[8],  12);
	ROUND(bbb, ccc, ddd, aaa, F3, KK2, in[12],  7);
	ROUND(aaa, bbb, ccc, ddd, F3, KK2, in[4],   6);
	ROUND(ddd, aaa, bbb, ccc, F3, KK2, in[9],  15);
	ROUND(ccc, ddd, aaa, bbb, F3, KK2, in[1],  13);
	ROUND(bbb, ccc, ddd, aaa, F3, KK2, in[2],  11);

	/* Swap contents of "b" registers */
	swap(bb, bbb);

	/* round 3: left lane */
	ROUND(aa, bb, cc, dd, F3, K3, in[3],  11);
	ROUND(dd, aa, bb, cc, F3, K3, in[10], 13);
	ROUND(cc, dd, aa, bb, F3, K3, in[14],  6);
	ROUND(bb, cc, dd, aa, F3, K3, in[4],   7);
	ROUND(aa, bb, cc, dd, F3, K3, in[9],  14);
	ROUND(dd, aa, bb, cc, F3, K3, in[15],  9);
	ROUND(cc, dd, aa, bb, F3, K3, in[8],  13);
	ROUND(bb, cc, dd, aa, F3, K3, in[1],  15);
	ROUND(aa, bb, cc, dd, F3, K3, in[2],  14);
	ROUND(dd, aa, bb, cc, F3, K3, in[7],   8);
	ROUND(cc, dd, aa, bb, F3, K3, in[0],  13);
	ROUND(bb, cc, dd, aa, F3, K3, in[6],   6);
	ROUND(aa, bb, cc, dd, F3, K3, in[13],  5);
	ROUND(dd, aa, bb, cc, F3, K3, in[11], 12);
	ROUND(cc, dd, aa, bb, F3, K3, in[5],   7);
	ROUND(bb, cc, dd, aa, F3, K3, in[12],  5);

	/* round 3: right lane */
	ROUND(aaa, bbb, ccc, ddd, F2, KK3, in[15],  9);
	ROUND(ddd, aaa, bbb, ccc, F2, KK3, in[5],   7);
	ROUND(ccc, ddd, aaa, bbb, F2, KK3, in[1],  15);
	ROUND(bbb, ccc, ddd, aaa, F2, KK3, in[3],  11);
	ROUND(aaa, bbb, ccc, ddd, F2, KK3, in[7],   8);
	ROUND(ddd, aaa, bbb, ccc, F2, KK3, in[14],  6);
	ROUND(ccc, ddd, aaa, bbb, F2, KK3, in[6],   6);
	ROUND(bbb, ccc, ddd, aaa, F2, KK3, in[9],  14);
	ROUND(aaa, bbb, ccc, ddd, F2, KK3, in[11], 12);
	ROUND(ddd, aaa, bbb, ccc, F2, KK3, in[8],  13);
	ROUND(ccc, ddd, aaa, bbb, F2, KK3, in[12],  5);
	ROUND(bbb, ccc, ddd, aaa, F2, KK3, in[2],  14);
	ROUND(aaa, bbb, ccc, ddd, F2, KK3, in[10], 13);
	ROUND(ddd, aaa, bbb, ccc, F2, KK3, in[0],  13);
	ROUND(ccc, ddd, aaa, bbb, F2, KK3, in[4],   7);
	ROUND(bbb, ccc, ddd, aaa, F2, KK3, in[13],  5);

	/* Swap contents of "c" registers */
	swap(cc, ccc);

	/* round 4: left lane */
	ROUND(aa, bb, cc, dd, F4, K4, in[1],  11);
	ROUND(dd, aa, bb, cc, F4, K4, in[9],  12);
	ROUND(cc, dd, aa, bb, F4, K4, in[11], 14);
	ROUND(bb, cc, dd, aa, F4, K4, in[10], 15);
	ROUND(aa, bb, cc, dd, F4, K4, in[0],  14);
	ROUND(dd, aa, bb, cc, F4, K4, in[8],  15);
	ROUND(cc, dd, aa, bb, F4, K4, in[12],  9);
	ROUND(bb, cc, dd, aa, F4, K4, in[4],   8);
	ROUND(aa, bb, cc, dd, F4, K4, in[13],  9);
	ROUND(dd, aa, bb, cc, F4, K4, in[3],  14);
	ROUND(cc, dd, aa, bb, F4, K4, in[7],   5);
	ROUND(bb, cc, dd, aa, F4, K4, in[15],  6);
	ROUND(aa, bb, cc, dd, F4, K4, in[14],  8);
	ROUND(dd, aa, bb, cc, F4, K4, in[5],   6);
	ROUND(cc, dd, aa, bb, F4, K4, in[6],   5);
	ROUND(bb, cc, dd, aa, F4, K4, in[2],  12);

	/* round 4: right lane */
	ROUND(aaa, bbb, ccc, ddd, F1, KK4, in[8],  15);
	ROUND(ddd, aaa, bbb, ccc, F1, KK4, in[6],   5);
	ROUND(ccc, ddd, aaa, bbb, F1, KK4, in[4],   8);
	ROUND(bbb, ccc, ddd, aaa, F1, KK4, in[1],  11);
	ROUND(aaa, bbb, ccc, ddd, F1, KK4, in[3],  14);
	ROUND(ddd, aaa, bbb, ccc, F1, KK4, in[11], 14);
	ROUND(ccc, ddd, aaa, bbb, F1, KK4, in[15],  6);
	ROUND(bbb, ccc, ddd, aaa, F1, KK4, in[0],  14);
	ROUND(aaa, bbb, ccc, ddd, F1, KK4, in[5],   6);
	ROUND(ddd, aaa, bbb, ccc, F1, KK4, in[12],  9);
	ROUND(ccc, ddd, aaa, bbb, F1, KK4, in[2],  12);
	ROUND(bbb, ccc, ddd, aaa, F1, KK4, in[13],  9);
	ROUND(aaa, bbb, ccc, ddd, F1, KK4, in[9],  12);
	ROUND(ddd, aaa, bbb, ccc, F1, KK4, in[7],   5);
	ROUND(ccc, ddd, aaa, bbb, F1, KK4, in[10], 15);
	ROUND(bbb, ccc, ddd, aaa, F1, KK4, in[14],  8);

	/* Swap contents of "d" registers */
	swap(dd, ddd);

	/* combine results */
	state[0] += aa;
	state[1] += bb;
	state[2] += cc;
	state[3] += dd;
	state[4] += aaa;
	state[5] += bbb;
	state[6] += ccc;
	state[7] += ddd;
}

static int rmd256_init(struct shash_desc *desc)
{
	struct rmd256_ctx *rctx = shash_desc_ctx(desc);

	rctx->byte_count = 0;

	rctx->state[0] = RMD_H0;
	rctx->state[1] = RMD_H1;
	rctx->state[2] = RMD_H2;
	rctx->state[3] = RMD_H3;
	rctx->state[4] = RMD_H5;
	rctx->state[5] = RMD_H6;
	rctx->state[6] = RMD_H7;
	rctx->state[7] = RMD_H8;

	memset(rctx->buffer, 0, sizeof(rctx->buffer));

	return 0;
}

static int rmd256_update(struct shash_desc *desc, const u8 *data,
			 unsigned int len)
{
	struct rmd256_ctx *rctx = shash_desc_ctx(desc);
	const u32 avail = sizeof(rctx->buffer) - (rctx->byte_count & 0x3f);

	rctx->byte_count += len;

	/* Enough space in buffer? If so copy and we're done */
	if (avail > len) {
		memcpy((char *)rctx->buffer + (sizeof(rctx->buffer) - avail),
		       data, len);
		goto out;
	}

	memcpy((char *)rctx->buffer + (sizeof(rctx->buffer) - avail),
	       data, avail);

	rmd256_transform(rctx->state, rctx->buffer);
	data += avail;
	len -= avail;

	while (len >= sizeof(rctx->buffer)) {
		memcpy(rctx->buffer, data, sizeof(rctx->buffer));
		rmd256_transform(rctx->state, rctx->buffer);
		data += sizeof(rctx->buffer);
		len -= sizeof(rctx->buffer);
	}

	memcpy(rctx->buffer, data, len);

out:
	return 0;
}

/* Add padding and return the message digest. */
static int rmd256_final(struct shash_desc *desc, u8 *out)
{
	struct rmd256_ctx *rctx = shash_desc_ctx(desc);
	u32 i, index, padlen;
	__le64 bits;
	__le32 *dst = (__le32 *)out;
	static const u8 padding[64] = { 0x80, };

	bits = cpu_to_le64(rctx->byte_count << 3);

	/* Pad out to 56 mod 64 */
	index = rctx->byte_count & 0x3f;
	padlen = (index < 56) ? (56 - index) : ((64+56) - index);
	rmd256_update(desc, padding, padlen);

	/* Append length */
	rmd256_update(desc, (const u8 *)&bits, sizeof(bits));

	/* Store state in digest */
	for (i = 0; i < 8; i++)
		dst[i] = cpu_to_le32p(&rctx->state[i]);

	/* Wipe context */
	memset(rctx, 0, sizeof(*rctx));

	return 0;
}

static struct shash_alg alg = {
	.digestsize	=	RMD256_DIGEST_SIZE,
	.init		=	rmd256_init,
	.update		=	rmd256_update,
	.final		=	rmd256_final,
	.descsize	=	sizeof(struct rmd256_ctx),
	.base		=	{
		.cra_name	 =	"rmd256",
		.cra_driver_name =	"rmd256-generic",
		.cra_blocksize	 =	RMD256_BLOCK_SIZE,
		.cra_module	 =	THIS_MODULE,
	}
};

static int __init rmd256_mod_init(void)
{
	return crypto_register_shash(&alg);
}

static void __exit rmd256_mod_fini(void)
{
	crypto_unregister_shash(&alg);
}

subsys_initcall(rmd256_mod_init);
module_exit(rmd256_mod_fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Adrian-Ken Rueegsegger <ken@codelabs.ch>");
MODULE_DESCRIPTION("RIPEMD-256 Message Digest");
MODULE_ALIAS_CRYPTO("rmd256");
back to top