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| author | Pan Bian <bianpan2016@163.com> | 2018-11-23 10:56:33 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-17 11:38:33 +0300 |
| commit | d2139ee71c89345e946f4df175d87bfce3dbe363 (patch) | |
| tree | e9dd2cc384ab013d8e16e34e5e516c3cd11e2e9f /fs/exportfs/expfs.c | |
| parent | 476a607331b7cc51a5283e344b11b19ac04ef72f (diff) | |
| download | linux-d2139ee71c89345e946f4df175d87bfce3dbe363.tar.xz | |
exportfs: do not read dentry after free
[ Upstream commit 2084ac6c505a58f7efdec13eba633c6aaa085ca5 ]
The function dentry_connected calls dput(dentry) to drop the previously
acquired reference to dentry. In this case, dentry can be released.
After that, IS_ROOT(dentry) checks the condition
(dentry == dentry->d_parent), which may result in a use-after-free bug.
This patch directly compares dentry with its parent obtained before
dropping the reference.
Fixes: a056cc8934c("exportfs: stop retrying once we race with
rename/remove")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/exportfs/expfs.c')
| -rw-r--r-- | fs/exportfs/expfs.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index a4b531be9168..7a7bba7c2328 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -76,7 +76,7 @@ static bool dentry_connected(struct dentry *dentry) struct dentry *parent = dget_parent(dentry); dput(dentry); - if (IS_ROOT(dentry)) { + if (dentry == parent) { dput(parent); return false; } |