This test tries to reproduce (with a moderate chance of success on ext4) a race condition where a file could be created in a directory concurrently to an encryption policy being set on that directory, causing the directory to become corrupted. Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> --- src/fscrypt_util.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++ tests/generic/402 | 39 ++++++++++++++++++++ tests/generic/402.out | 2 ++ tests/generic/group | 1 + 4 files changed, 140 insertions(+) create mode 100755 tests/generic/402 create mode 100644 tests/generic/402.out diff --git a/src/fscrypt_util.c b/src/fscrypt_util.c index 9428cb4..5ca0996 100644 --- a/src/fscrypt_util.c +++ b/src/fscrypt_util.c @@ -19,11 +19,13 @@ * along with this program; if not, see <http://www.gnu.org/licenses/>. */ +#include <dirent.h> #include <errno.h> #include <fcntl.h> #include <inttypes.h> #include <linux/fs.h> #include <linux/keyctl.h> +#include <pthread.h> #include <stdarg.h> #include <stdbool.h> #include <stdio.h> @@ -97,6 +99,7 @@ usage(void) " fscrypt_util rm_key KEYDESC\n" " fscrypt_util set_policy KEYDESC DIR\n" " fscrypt_util test_ioctl_validation DIR\n" +" fscrypt_util test_set_policy_locking DIR\n" ); exit(2); } @@ -357,6 +360,100 @@ static int test_ioctl_validation(int argc, char **argv) return 0; } +struct subdir_thread_args { + pthread_cond_t cond; + pthread_mutex_t mutex; + char *subdir; + bool done; +}; + +static void *subdir_thrproc(void *arg) +{ + struct subdir_thread_args *args = arg; + + pthread_mutex_lock(&args->mutex); + while (!args->done) { + pthread_cond_wait(&args->cond, &args->mutex); + mkdir(args->subdir, 0755); + } + pthread_mutex_unlock(&args->mutex); + return NULL; +} + +/* + * Test that FS_IOC_SET_ENCRYPTION_POLICY is correctly serialized with regard to + * creation of new files in the directory. + * + * To test this we repeatedly attempt to create a subdirectory concurrently with + * setting an encryption policy on the parent directory. After each attempt, we + * do readdir() on the directory. readdir() should always succeed regardless of + * whether the directory ended up with an encryption policy or not. But without + * the proper locking of the directory inode, on ext4 it sometimes failed with + * EUCLEAN, and the filesystem was also left in an inconsistent state for fsck. + */ +static int test_set_policy_locking(int argc, char **argv) +{ + const char *dir; + struct subdir_thread_args args; + pthread_t subdir_thread; + struct fscrypt_policy policy; + int i; + + if (argc != 1) + usage(); + dir = argv[0]; + + args.subdir = malloc(strlen(dir) + 8); + sprintf(args.subdir, "%s/subdir", dir); + pthread_cond_init(&args.cond, NULL); + pthread_mutex_init(&args.mutex, NULL); + args.done = false; + + if (pthread_create(&subdir_thread, NULL, subdir_thrproc, &args) != 0) + die("Unable to create thread"); + + init_policy_default(&policy); + + for (i = 0; i < 20000; i++) { + int fd; + DIR *d; + + rmdir(args.subdir); + rmdir(dir); + mkdir(dir, 0755); + fd = open(dir, O_RDONLY); + pthread_mutex_lock(&args.mutex); + pthread_cond_signal(&args.cond); + pthread_mutex_unlock(&args.mutex); + if (ioctl(fd, FS_IOC_SET_ENCRYPTION_POLICY, &policy) != 0 && + errno != ENOTEMPTY) { + die_errno("Unexpected error from " + "FS_IOC_SET_ENCRYPTION_POLICY"); + } + d = fdopendir(fd); + if (!d) + die_errno("Unexpected fdopendir() error"); + errno = 0; + while (readdir(d) != NULL) + ; + if (errno != 0) + die_errno("Unexpected readdir() error"); + closedir(d); + } + + pthread_mutex_lock(&args.mutex); + args.done = true; + pthread_cond_signal(&args.cond); + pthread_mutex_unlock(&args.mutex); + + if (pthread_join(subdir_thread, NULL) != 0) + die("Unable to join thread"); + + free(args.subdir); + printf("%s: test_set_policy_locking passed\n", dir); + return 0; +} + static const struct command { const char *name; int (*func)(int, char **); @@ -365,6 +462,7 @@ static const struct command { {"rm_key", rm_key}, {"set_policy", set_policy}, {"test_ioctl_validation", test_ioctl_validation}, + {"test_set_policy_locking", test_set_policy_locking}, {NULL, NULL} }; diff --git a/tests/generic/402 b/tests/generic/402 new file mode 100755 index 0000000..e26c0c9 --- /dev/null +++ b/tests/generic/402 @@ -0,0 +1,39 @@ +#!/bin/bash +# FS QA Test generic/402 +# +# The FS_IOC_SET_ENCRYPTION_POLICY ioctl must be correctly serialized with +# regard to creation of new files in the directory. Regression test for +# 8906a8223ad4: "fscrypto: lock inode while setting encryption policy". +# +#----------------------------------------------------------------------- +# Copyright (C) 2016 Google, Inc. +# +# Author: Eric Biggers <ebiggers@xxxxxxxxxx> +# +# 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. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, see <http://www.gnu.org/licenses/>. +#----------------------------------------------------------------------- + +seq=`basename $0` +seqres=$RESULT_DIR/$seq +echo "QA output created by $seq" + +. ./common/encrypt + +_begin_encryption_test + +cd $SCRATCH_MNT +mkdir dir +$FSCRYPT_UTIL test_set_policy_locking dir + +exit 0 diff --git a/tests/generic/402.out b/tests/generic/402.out new file mode 100644 index 0000000..947e830 --- /dev/null +++ b/tests/generic/402.out @@ -0,0 +1,2 @@ +QA output created by 402 +dir: test_set_policy_locking passed diff --git a/tests/generic/group b/tests/generic/group index ab4edae..ed6b926 100644 --- a/tests/generic/group +++ b/tests/generic/group @@ -394,3 +394,4 @@ 389 auto quick acl 400 auto quick encrypt 401 auto quick encrypt +402 auto encrypt -- 2.8.0.rc3.226.g39d4020 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
