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authorTianjia Zhang <tianjia.zhang@linux.alibaba.com>2023-06-01 14:42:44 +0800
committerMimi Zohar <zohar@linux.ibm.com>2023-06-01 07:25:04 -0400
commit9df6a4870dc371136e90330cfbbc51464ee66993 (patch)
tree7dd5e36322665b0ce299910dcea5758df8b32dc7 /security
parentdb1d1e8b9867aae5c3e61ad7859abfcc4a6fd6c7 (diff)
integrity: Fix possible multiple allocation in integrity_inode_get()
When integrity_inode_get() is querying and inserting the cache, there is a conditional race in the concurrent environment. The race condition is the result of not properly implementing "double-checked locking". In this case, it first checks to see if the iint cache record exists before taking the lock, but doesn't check again after taking the integrity_iint_lock. Fixes: bf2276d10ce5 ("ima: allocating iint improvements") Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com> Cc: <stable@vger.kernel.org> # v3.10+ Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/iint.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index c73858e8c6d5..a462df827de2 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -43,12 +43,10 @@ static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
else if (inode > iint->inode)
n = n->rb_right;
else
- break;
+ return iint;
}
- if (!n)
- return NULL;
- return iint;
+ return NULL;
}
/*
@@ -113,10 +111,15 @@ struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
parent = *p;
test_iint = rb_entry(parent, struct integrity_iint_cache,
rb_node);
- if (inode < test_iint->inode)
+ if (inode < test_iint->inode) {
p = &(*p)->rb_left;
- else
+ } else if (inode > test_iint->inode) {
p = &(*p)->rb_right;
+ } else {
+ write_unlock(&integrity_iint_lock);
+ kmem_cache_free(iint_cache, iint);
+ return test_iint;
+ }
}
iint->inode = inode;