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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2011-04-03 00:09:26 +0900
committerJames Morris <jmorris@namei.org>2011-04-19 09:37:06 +1000
commit2a086e5d3a23570735f75b784d29b93068070833 (patch)
tree43949632ba2e1c8ed4a8169d64c406d66ce36f23 /security/tomoyo
parenta3232d2fa2e3cbab3e76d91cdae5890fee8a4034 (diff)
TOMOYO: Fix race on updating profile's comment line.
In tomoyo_write_profile() since 2.6.34, a lock was by error missing when replacing profile's comment line. If multiple threads attempted echo '0-COMMENT=comment' > /sys/kernel/security/tomoyo/profile in parallel, garbage collector will fail to kfree() the old value. Protect the replacement using a lock. Also, keep the old value rather than replace with empty string when out of memory error has occurred. Signed-off-by: Xiaochen Wang <wangxiaochen0@gmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/tomoyo')
-rw-r--r--security/tomoyo/common.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index 7556315c197..2b7b1a12360 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -459,8 +459,16 @@ static int tomoyo_write_profile(struct tomoyo_io_buffer *head)
if (profile == &tomoyo_default_profile)
return -EINVAL;
if (!strcmp(data, "COMMENT")) {
- const struct tomoyo_path_info *old_comment = profile->comment;
- profile->comment = tomoyo_get_name(cp);
+ static DEFINE_SPINLOCK(lock);
+ const struct tomoyo_path_info *new_comment
+ = tomoyo_get_name(cp);
+ const struct tomoyo_path_info *old_comment;
+ if (!new_comment)
+ return -ENOMEM;
+ spin_lock(&lock);
+ old_comment = profile->comment;
+ profile->comment = new_comment;
+ spin_unlock(&lock);
tomoyo_put_name(old_comment);
return 0;
}