| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 131/140] fscrypto: lock inode while setting encryption policy | Date | Wed, 26 Oct 2016 14:23:11 +0200 |
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4.8-stable review patch. If anyone has any objections, please let me know.
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From: Eric Biggers <ebiggers@google.com>
commit 8906a8223ad4909b391c5628f7991ebceda30e52 upstream.
i_rwsem needs to be acquired while setting an encryption policy so that concurrent calls to FS_IOC_SET_ENCRYPTION_POLICY are correctly serialized (especially the ->get_context() + ->set_context() pair), and so that new files cannot be created in the directory during or after the ->empty_dir() check.
Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Richard Weinberger <richard@nod.at> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/crypto/policy.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -109,6 +109,8 @@ int fscrypt_process_policy(struct file * if (ret) return ret; + inode_lock(inode); + if (!inode_has_encryption_context(inode)) { if (!S_ISDIR(inode->i_mode)) ret = -EINVAL; @@ -127,6 +129,8 @@ int fscrypt_process_policy(struct file * ret = -EINVAL; } + inode_unlock(inode); + mnt_drop_write_file(filp); return ret; }
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