On a filesystem with encryption enabled, a user could set an encryption
policy on any empty directory to which they have readonly access. This
is a potential security issue since such a directory might be owned by
another user, and the new encryption policy may prevent that user from
creating files in their own directory.
Fix this by requiring inode_owner_or_capable() permission to set an
encryption policy.
Signed-off-by: Eric Biggers <ebiggers3@xxxxxxxxx>
---
fs/crypto/policy.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index cb5ba27..3f5c275 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -96,6 +96,9 @@ int fscrypt_set_policy(struct inode *inode, const struct fscrypt_policy *policy)
{
int ret = 0;
+ if (!inode_owner_or_capable(inode))
+ return -EACCES;
+
if (policy->version != 0)
return -EINVAL;
--
2.7.4
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