mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 08:19:28 +00:00
![Eric Biggers](/assets/img/avatar_default.png)
commit12d41a023e
upstream. When setting the secret with the software Diffie-Hellman implementation, if allocating 'g' failed (e.g. if it was longer than MAX_EXTERN_MPI_BITS), then 'p' was freed twice: once immediately, and once later when the crypto_kpp tfm was destroyed. Fix it by using dh_free_ctx() (renamed to dh_clear_ctx()) in the error paths, as that correctly sets the pointers to NULL. KASAN report: MPI: mpi too large (32760 bits) ================================================================== BUG: KASAN: use-after-free in mpi_free+0x131/0x170 Read of size 4 at addr ffff88006c7cdf90 by task reproduce_doubl/367 CPU: 1 PID: 367 Comm: reproduce_doubl Not tainted 4.14.0-rc7-00040-g05298abde6fe #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0xb3/0x10b ? mpi_free+0x131/0x170 print_address_description+0x79/0x2a0 ? mpi_free+0x131/0x170 kasan_report+0x236/0x340 ? akcipher_register_instance+0x90/0x90 __asan_report_load4_noabort+0x14/0x20 mpi_free+0x131/0x170 ? akcipher_register_instance+0x90/0x90 dh_exit_tfm+0x3d/0x140 crypto_kpp_exit_tfm+0x52/0x70 crypto_destroy_tfm+0xb3/0x250 __keyctl_dh_compute+0x640/0xe90 ? kasan_slab_free+0x12f/0x180 ? dh_data_from_key+0x240/0x240 ? key_create_or_update+0x1ee/0xb20 ? key_instantiate_and_link+0x440/0x440 ? lock_contended+0xee0/0xee0 ? kfree+0xcf/0x210 ? SyS_add_key+0x268/0x340 keyctl_dh_compute+0xb3/0xf1 ? __keyctl_dh_compute+0xe90/0xe90 ? SyS_add_key+0x26d/0x340 ? entry_SYSCALL_64_fastpath+0x5/0xbe ? trace_hardirqs_on_caller+0x3f4/0x560 SyS_keyctl+0x72/0x2c0 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x43ccf9 RSP: 002b:00007ffeeec96158 EFLAGS: 00000246 ORIG_RAX: 00000000000000fa RAX: ffffffffffffffda RBX: 000000000248b9b9 RCX: 000000000043ccf9 RDX: 00007ffeeec96170 RSI: 00007ffeeec96160 RDI: 0000000000000017 RBP: 0000000000000046 R08: 0000000000000000 R09: 0248b9b9143dc936 R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000409670 R14: 0000000000409700 R15: 0000000000000000 Allocated by task 367: save_stack_trace+0x16/0x20 kasan_kmalloc+0xeb/0x180 kmem_cache_alloc_trace+0x114/0x300 mpi_alloc+0x4b/0x230 mpi_read_raw_data+0xbe/0x360 dh_set_secret+0x1dc/0x460 __keyctl_dh_compute+0x623/0xe90 keyctl_dh_compute+0xb3/0xf1 SyS_keyctl+0x72/0x2c0 entry_SYSCALL_64_fastpath+0x1f/0xbe Freed by task 367: save_stack_trace+0x16/0x20 kasan_slab_free+0xab/0x180 kfree+0xb5/0x210 mpi_free+0xcb/0x170 dh_set_secret+0x2d7/0x460 __keyctl_dh_compute+0x623/0xe90 keyctl_dh_compute+0xb3/0xf1 SyS_keyctl+0x72/0x2c0 entry_SYSCALL_64_fastpath+0x1f/0xbe Fixes:802c7f1c84
("crypto: dh - Add DH software implementation") Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
186 lines
3.7 KiB
C
186 lines
3.7 KiB
C
/* Diffie-Hellman Key Agreement Method [RFC2631]
|
|
*
|
|
* Copyright (c) 2016, Intel Corporation
|
|
* Authors: Salvatore Benedetto <salvatore.benedetto@intel.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/module.h>
|
|
#include <crypto/internal/kpp.h>
|
|
#include <crypto/kpp.h>
|
|
#include <crypto/dh.h>
|
|
#include <linux/mpi.h>
|
|
|
|
struct dh_ctx {
|
|
MPI p;
|
|
MPI g;
|
|
MPI xa;
|
|
};
|
|
|
|
static void dh_clear_ctx(struct dh_ctx *ctx)
|
|
{
|
|
mpi_free(ctx->p);
|
|
mpi_free(ctx->g);
|
|
mpi_free(ctx->xa);
|
|
memset(ctx, 0, sizeof(*ctx));
|
|
}
|
|
|
|
/*
|
|
* If base is g we compute the public key
|
|
* ya = g^xa mod p; [RFC2631 sec 2.1.1]
|
|
* else if base if the counterpart public key we compute the shared secret
|
|
* ZZ = yb^xa mod p; [RFC2631 sec 2.1.1]
|
|
*/
|
|
static int _compute_val(const struct dh_ctx *ctx, MPI base, MPI val)
|
|
{
|
|
/* val = base^xa mod p */
|
|
return mpi_powm(val, base, ctx->xa, ctx->p);
|
|
}
|
|
|
|
static inline struct dh_ctx *dh_get_ctx(struct crypto_kpp *tfm)
|
|
{
|
|
return kpp_tfm_ctx(tfm);
|
|
}
|
|
|
|
static int dh_check_params_length(unsigned int p_len)
|
|
{
|
|
return (p_len < 1536) ? -EINVAL : 0;
|
|
}
|
|
|
|
static int dh_set_params(struct dh_ctx *ctx, struct dh *params)
|
|
{
|
|
if (unlikely(!params->p || !params->g))
|
|
return -EINVAL;
|
|
|
|
if (dh_check_params_length(params->p_size << 3))
|
|
return -EINVAL;
|
|
|
|
ctx->p = mpi_read_raw_data(params->p, params->p_size);
|
|
if (!ctx->p)
|
|
return -EINVAL;
|
|
|
|
ctx->g = mpi_read_raw_data(params->g, params->g_size);
|
|
if (!ctx->g)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int dh_set_secret(struct crypto_kpp *tfm, const void *buf,
|
|
unsigned int len)
|
|
{
|
|
struct dh_ctx *ctx = dh_get_ctx(tfm);
|
|
struct dh params;
|
|
|
|
/* Free the old MPI key if any */
|
|
dh_clear_ctx(ctx);
|
|
|
|
if (crypto_dh_decode_key(buf, len, ¶ms) < 0)
|
|
goto err_clear_ctx;
|
|
|
|
if (dh_set_params(ctx, ¶ms) < 0)
|
|
goto err_clear_ctx;
|
|
|
|
ctx->xa = mpi_read_raw_data(params.key, params.key_size);
|
|
if (!ctx->xa)
|
|
goto err_clear_ctx;
|
|
|
|
return 0;
|
|
|
|
err_clear_ctx:
|
|
dh_clear_ctx(ctx);
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int dh_compute_value(struct kpp_request *req)
|
|
{
|
|
struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
|
|
struct dh_ctx *ctx = dh_get_ctx(tfm);
|
|
MPI base, val = mpi_alloc(0);
|
|
int ret = 0;
|
|
int sign;
|
|
|
|
if (!val)
|
|
return -ENOMEM;
|
|
|
|
if (unlikely(!ctx->xa)) {
|
|
ret = -EINVAL;
|
|
goto err_free_val;
|
|
}
|
|
|
|
if (req->src) {
|
|
base = mpi_read_raw_from_sgl(req->src, req->src_len);
|
|
if (!base) {
|
|
ret = -EINVAL;
|
|
goto err_free_val;
|
|
}
|
|
} else {
|
|
base = ctx->g;
|
|
}
|
|
|
|
ret = _compute_val(ctx, base, val);
|
|
if (ret)
|
|
goto err_free_base;
|
|
|
|
ret = mpi_write_to_sgl(val, req->dst, req->dst_len, &sign);
|
|
if (ret)
|
|
goto err_free_base;
|
|
|
|
if (sign < 0)
|
|
ret = -EBADMSG;
|
|
err_free_base:
|
|
if (req->src)
|
|
mpi_free(base);
|
|
err_free_val:
|
|
mpi_free(val);
|
|
return ret;
|
|
}
|
|
|
|
static unsigned int dh_max_size(struct crypto_kpp *tfm)
|
|
{
|
|
struct dh_ctx *ctx = dh_get_ctx(tfm);
|
|
|
|
return mpi_get_size(ctx->p);
|
|
}
|
|
|
|
static void dh_exit_tfm(struct crypto_kpp *tfm)
|
|
{
|
|
struct dh_ctx *ctx = dh_get_ctx(tfm);
|
|
|
|
dh_clear_ctx(ctx);
|
|
}
|
|
|
|
static struct kpp_alg dh = {
|
|
.set_secret = dh_set_secret,
|
|
.generate_public_key = dh_compute_value,
|
|
.compute_shared_secret = dh_compute_value,
|
|
.max_size = dh_max_size,
|
|
.exit = dh_exit_tfm,
|
|
.base = {
|
|
.cra_name = "dh",
|
|
.cra_driver_name = "dh-generic",
|
|
.cra_priority = 100,
|
|
.cra_module = THIS_MODULE,
|
|
.cra_ctxsize = sizeof(struct dh_ctx),
|
|
},
|
|
};
|
|
|
|
static int dh_init(void)
|
|
{
|
|
return crypto_register_kpp(&dh);
|
|
}
|
|
|
|
static void dh_exit(void)
|
|
{
|
|
crypto_unregister_kpp(&dh);
|
|
}
|
|
|
|
module_init(dh_init);
|
|
module_exit(dh_exit);
|
|
MODULE_ALIAS_CRYPTO("dh");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("DH generic algorithm");
|