Revision 7561cea5dbb97fecb952548a0fb74fb105bf4664 authored by Darrick J. Wong on 01 July 2022, 16:08:33 UTC, committed by Darrick J. Wong on 01 July 2022, 16:09:52 UTC
KASAN reported the following use after free bug when running generic/475: XFS (dm-0): Mounting V5 Filesystem XFS (dm-0): Starting recovery (logdev: internal) XFS (dm-0): Ending recovery (logdev: internal) Buffer I/O error on dev dm-0, logical block 20639616, async page read Buffer I/O error on dev dm-0, logical block 20639617, async page read XFS (dm-0): log I/O error -5 XFS (dm-0): Filesystem has been shut down due to log error (0x2). XFS (dm-0): Unmounting Filesystem XFS (dm-0): Please unmount the filesystem and rectify the problem(s). ================================================================== BUG: KASAN: use-after-free in do_raw_spin_lock+0x246/0x270 Read of size 4 at addr ffff888109dd84c4 by task 3:1H/136 CPU: 3 PID: 136 Comm: 3:1H Not tainted 5.19.0-rc4-xfsx #rc4 8e53ab5ad0fddeb31cee5e7063ff9c361915a9c4 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 Workqueue: xfs-log/dm-0 xlog_ioend_work [xfs] Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_report.cold+0x2b8/0x661 ? do_raw_spin_lock+0x246/0x270 kasan_report+0xab/0x120 ? do_raw_spin_lock+0x246/0x270 do_raw_spin_lock+0x246/0x270 ? rwlock_bug.part.0+0x90/0x90 xlog_force_shutdown+0xf6/0x370 [xfs 4ad76ae0d6add7e8183a553e624c31e9ed567318] xlog_ioend_work+0x100/0x190 [xfs 4ad76ae0d6add7e8183a553e624c31e9ed567318] process_one_work+0x672/0x1040 worker_thread+0x59b/0xec0 ? __kthread_parkme+0xc6/0x1f0 ? process_one_work+0x1040/0x1040 ? process_one_work+0x1040/0x1040 kthread+0x29e/0x340 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 </TASK> Allocated by task 154099: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x81/0xa0 kmem_alloc+0x8d/0x2e0 [xfs] xlog_cil_init+0x1f/0x540 [xfs] xlog_alloc_log+0xd1e/0x1260 [xfs] xfs_log_mount+0xba/0x640 [xfs] xfs_mountfs+0xf2b/0x1d00 [xfs] xfs_fs_fill_super+0x10af/0x1910 [xfs] get_tree_bdev+0x383/0x670 vfs_get_tree+0x7d/0x240 path_mount+0xdb7/0x1890 __x64_sys_mount+0x1fa/0x270 do_syscall_64+0x2b/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Freed by task 154151: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_set_free_info+0x20/0x30 ____kasan_slab_free+0x110/0x190 slab_free_freelist_hook+0xab/0x180 kfree+0xbc/0x310 xlog_dealloc_log+0x1b/0x2b0 [xfs] xfs_unmountfs+0x119/0x200 [xfs] xfs_fs_put_super+0x6e/0x2e0 [xfs] generic_shutdown_super+0x12b/0x3a0 kill_block_super+0x95/0xd0 deactivate_locked_super+0x80/0x130 cleanup_mnt+0x329/0x4d0 task_work_run+0xc5/0x160 exit_to_user_mode_prepare+0xd4/0xe0 syscall_exit_to_user_mode+0x1d/0x40 entry_SYSCALL_64_after_hwframe+0x46/0xb0 This appears to be a race between the unmount process, which frees the CIL and waits for in-flight iclog IO; and the iclog IO completion. When generic/475 runs, it starts fsstress in the background, waits a few seconds, and substitutes a dm-error device to simulate a disk falling out of a machine. If the fsstress encounters EIO on a pure data write, it will exit but the filesystem will still be online. The next thing the test does is unmount the filesystem, which tries to clean the log, free the CIL, and wait for iclog IO completion. If an iclog was being written when the dm-error switch occurred, it can race with log unmounting as follows: Thread 1 Thread 2 xfs_log_unmount xfs_log_clean xfs_log_quiesce xlog_ioend_work <observe error> xlog_force_shutdown test_and_set_bit(XLOG_IOERROR) xfs_log_force <log is shut down, nop> xfs_log_umount_write <log is shut down, nop> xlog_dealloc_log xlog_cil_destroy <wait for iclogs> spin_lock(&log->l_cilp->xc_push_lock) <KABOOM> Therefore, free the CIL after waiting for the iclogs to complete. I /think/ this race has existed for quite a few years now, though I don't remember the ~2014 era logging code well enough to know if it was a real threat then or if the actual race was exposed only more recently. Fixes: ac983517ec59 ("xfs: don't sleep in xlog_cil_force_lsn on shutdown") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
1 parent 8944c6f
authenc.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Authenc: Simple AEAD wrapper for IPsec
*
* Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <crypto/internal/aead.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/authenc.h>
#include <crypto/null.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
struct authenc_instance_ctx {
struct crypto_ahash_spawn auth;
struct crypto_skcipher_spawn enc;
unsigned int reqoff;
};
struct crypto_authenc_ctx {
struct crypto_ahash *auth;
struct crypto_skcipher *enc;
struct crypto_sync_skcipher *null;
};
struct authenc_request_ctx {
struct scatterlist src[2];
struct scatterlist dst[2];
char tail[];
};
static void authenc_request_complete(struct aead_request *req, int err)
{
if (err != -EINPROGRESS)
aead_request_complete(req, err);
}
int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key,
unsigned int keylen)
{
struct rtattr *rta = (struct rtattr *)key;
struct crypto_authenc_key_param *param;
if (!RTA_OK(rta, keylen))
return -EINVAL;
if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
return -EINVAL;
/*
* RTA_OK() didn't align the rtattr's payload when validating that it
* fits in the buffer. Yet, the keys should start on the next 4-byte
* aligned boundary. To avoid confusion, require that the rtattr
* payload be exactly the param struct, which has a 4-byte aligned size.
*/
if (RTA_PAYLOAD(rta) != sizeof(*param))
return -EINVAL;
BUILD_BUG_ON(sizeof(*param) % RTA_ALIGNTO);
param = RTA_DATA(rta);
keys->enckeylen = be32_to_cpu(param->enckeylen);
key += rta->rta_len;
keylen -= rta->rta_len;
if (keylen < keys->enckeylen)
return -EINVAL;
keys->authkeylen = keylen - keys->enckeylen;
keys->authkey = key;
keys->enckey = key + keys->authkeylen;
return 0;
}
EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys);
static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
unsigned int keylen)
{
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct crypto_ahash *auth = ctx->auth;
struct crypto_skcipher *enc = ctx->enc;
struct crypto_authenc_keys keys;
int err = -EINVAL;
if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
goto out;
crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) &
CRYPTO_TFM_REQ_MASK);
err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
if (err)
goto out;
crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
CRYPTO_TFM_REQ_MASK);
err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
out:
memzero_explicit(&keys, sizeof(keys));
return err;
}
static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct aead_instance *inst = aead_alg_instance(authenc);
struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
if (err)
goto out;
scatterwalk_map_and_copy(ahreq->result, req->dst,
req->assoclen + req->cryptlen,
crypto_aead_authsize(authenc), 1);
out:
aead_request_complete(req, err);
}
static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct aead_instance *inst = aead_alg_instance(authenc);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
struct crypto_ahash *auth = ctx->auth;
struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
u8 *hash = areq_ctx->tail;
int err;
hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth),
crypto_ahash_alignmask(auth) + 1);
ahash_request_set_tfm(ahreq, auth);
ahash_request_set_crypt(ahreq, req->dst, hash,
req->assoclen + req->cryptlen);
ahash_request_set_callback(ahreq, flags,
authenc_geniv_ahash_done, req);
err = crypto_ahash_digest(ahreq);
if (err)
return err;
scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen,
crypto_aead_authsize(authenc), 1);
return 0;
}
static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
int err)
{
struct aead_request *areq = req->data;
if (err)
goto out;
err = crypto_authenc_genicv(areq, 0);
out:
authenc_request_complete(areq, err);
}
static int crypto_authenc_copy_assoc(struct aead_request *req)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
skcipher_request_set_sync_tfm(skreq, ctx->null);
skcipher_request_set_callback(skreq, aead_request_flags(req),
NULL, NULL);
skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen,
NULL);
return crypto_skcipher_encrypt(skreq);
}
static int crypto_authenc_encrypt(struct aead_request *req)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct aead_instance *inst = aead_alg_instance(authenc);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
struct crypto_skcipher *enc = ctx->enc;
unsigned int cryptlen = req->cryptlen;
struct skcipher_request *skreq = (void *)(areq_ctx->tail +
ictx->reqoff);
struct scatterlist *src, *dst;
int err;
src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
dst = src;
if (req->src != req->dst) {
err = crypto_authenc_copy_assoc(req);
if (err)
return err;
dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
}
skcipher_request_set_tfm(skreq, enc);
skcipher_request_set_callback(skreq, aead_request_flags(req),
crypto_authenc_encrypt_done, req);
skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
err = crypto_skcipher_encrypt(skreq);
if (err)
return err;
return crypto_authenc_genicv(req, aead_request_flags(req));
}
static int crypto_authenc_decrypt_tail(struct aead_request *req,
unsigned int flags)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct aead_instance *inst = aead_alg_instance(authenc);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
struct skcipher_request *skreq = (void *)(areq_ctx->tail +
ictx->reqoff);
unsigned int authsize = crypto_aead_authsize(authenc);
u8 *ihash = ahreq->result + authsize;
struct scatterlist *src, *dst;
scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0);
if (crypto_memneq(ihash, ahreq->result, authsize))
return -EBADMSG;
src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
dst = src;
if (req->src != req->dst)
dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
skcipher_request_set_tfm(skreq, ctx->enc);
skcipher_request_set_callback(skreq, flags,
req->base.complete, req->base.data);
skcipher_request_set_crypt(skreq, src, dst,
req->cryptlen - authsize, req->iv);
return crypto_skcipher_decrypt(skreq);
}
static void authenc_verify_ahash_done(struct crypto_async_request *areq,
int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = crypto_authenc_decrypt_tail(req, 0);
out:
authenc_request_complete(req, err);
}
static int crypto_authenc_decrypt(struct aead_request *req)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
unsigned int authsize = crypto_aead_authsize(authenc);
struct aead_instance *inst = aead_alg_instance(authenc);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
struct crypto_ahash *auth = ctx->auth;
struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
u8 *hash = areq_ctx->tail;
int err;
hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth),
crypto_ahash_alignmask(auth) + 1);
ahash_request_set_tfm(ahreq, auth);
ahash_request_set_crypt(ahreq, req->src, hash,
req->assoclen + req->cryptlen - authsize);
ahash_request_set_callback(ahreq, aead_request_flags(req),
authenc_verify_ahash_done, req);
err = crypto_ahash_digest(ahreq);
if (err)
return err;
return crypto_authenc_decrypt_tail(req, aead_request_flags(req));
}
static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
{
struct aead_instance *inst = aead_alg_instance(tfm);
struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_ahash *auth;
struct crypto_skcipher *enc;
struct crypto_sync_skcipher *null;
int err;
auth = crypto_spawn_ahash(&ictx->auth);
if (IS_ERR(auth))
return PTR_ERR(auth);
enc = crypto_spawn_skcipher(&ictx->enc);
err = PTR_ERR(enc);
if (IS_ERR(enc))
goto err_free_ahash;
null = crypto_get_default_null_skcipher();
err = PTR_ERR(null);
if (IS_ERR(null))
goto err_free_skcipher;
ctx->auth = auth;
ctx->enc = enc;
ctx->null = null;
crypto_aead_set_reqsize(
tfm,
sizeof(struct authenc_request_ctx) +
ictx->reqoff +
max_t(unsigned int,
crypto_ahash_reqsize(auth) +
sizeof(struct ahash_request),
sizeof(struct skcipher_request) +
crypto_skcipher_reqsize(enc)));
return 0;
err_free_skcipher:
crypto_free_skcipher(enc);
err_free_ahash:
crypto_free_ahash(auth);
return err;
}
static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
{
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_ahash(ctx->auth);
crypto_free_skcipher(ctx->enc);
crypto_put_default_null_skcipher();
}
static void crypto_authenc_free(struct aead_instance *inst)
{
struct authenc_instance_ctx *ctx = aead_instance_ctx(inst);
crypto_drop_skcipher(&ctx->enc);
crypto_drop_ahash(&ctx->auth);
kfree(inst);
}
static int crypto_authenc_create(struct crypto_template *tmpl,
struct rtattr **tb)
{
u32 mask;
struct aead_instance *inst;
struct authenc_instance_ctx *ctx;
struct hash_alg_common *auth;
struct crypto_alg *auth_base;
struct skcipher_alg *enc;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
if (err)
return err;
inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
return -ENOMEM;
ctx = aead_instance_ctx(inst);
err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), 0, mask);
if (err)
goto err_free_inst;
auth = crypto_spawn_ahash_alg(&ctx->auth);
auth_base = &auth->base;
err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
crypto_attr_alg_name(tb[2]), 0, mask);
if (err)
goto err_free_inst;
enc = crypto_spawn_skcipher_alg(&ctx->enc);
ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask,
auth_base->cra_alignmask + 1);
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"authenc(%s,%s)", auth_base->cra_name,
enc->base.cra_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"authenc(%s,%s)", auth_base->cra_driver_name,
enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
auth_base->cra_priority;
inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
enc->base.cra_alignmask;
inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
inst->alg.maxauthsize = auth->digestsize;
inst->alg.init = crypto_authenc_init_tfm;
inst->alg.exit = crypto_authenc_exit_tfm;
inst->alg.setkey = crypto_authenc_setkey;
inst->alg.encrypt = crypto_authenc_encrypt;
inst->alg.decrypt = crypto_authenc_decrypt;
inst->free = crypto_authenc_free;
err = aead_register_instance(tmpl, inst);
if (err) {
err_free_inst:
crypto_authenc_free(inst);
}
return err;
}
static struct crypto_template crypto_authenc_tmpl = {
.name = "authenc",
.create = crypto_authenc_create,
.module = THIS_MODULE,
};
static int __init crypto_authenc_module_init(void)
{
return crypto_register_template(&crypto_authenc_tmpl);
}
static void __exit crypto_authenc_module_exit(void)
{
crypto_unregister_template(&crypto_authenc_tmpl);
}
subsys_initcall(crypto_authenc_module_init);
module_exit(crypto_authenc_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
MODULE_ALIAS_CRYPTO("authenc");
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