From e9e360b08a44098ec6f31de8e5a29a3ffaada828 Mon Sep 17 00:00:00 2001
From: Namhyung Kim <namhyung@kernel.org>
Date: Wed, 19 Oct 2016 10:23:40 +0900
Subject: [PATCH] pstore: Protect unlink with read_mutex
When update_ms is set, pstore_get_records() will be called when there's
a new entry. But unlink can be called at the same time and might
contend with the open-read-close loop. Depending on the implementation
of platform driver, it may be safe or not. But I think it'd be better
to protect those race in the first place.
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
fs/pstore/inode.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 0d6bbcf47d524..57c0646479f51 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -199,11 +199,14 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
if (err)
return err;
- if (p->psi->erase)
+ if (p->psi->erase) {
+ mutex_lock(&p->psi->read_mutex);
p->psi->erase(p->type, p->id, p->count,
d_inode(dentry)->i_ctime, p->psi);
- else
+ mutex_unlock(&p->psi->read_mutex);
+ } else {
return -EPERM;
+ }
return simple_unlink(dir, dentry);
}
--
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