| Message ID | aa40bc0b110601d20cd49e1db1d2435d07da26b2.1666651724.git.sweettea-kernel@dorminy.me (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: add fscrypt integration | expand |
On Mon, Oct 24, 2022 at 07:13:12PM -0400, Sweet Tea Dorminy wrote: > From: Omar Sandoval <osandov@osandov.com> > > Btrfs will need to check whether inode policies are identical for > various purposes: if two inodes want to share an extent, they must have > the same policy, including key identifier; symlinks must not span the > encrypted/unencrypted border; and certain encryption policies will allow > btrfs to store one fscrypt_context for multiple objects. Therefore, add > a function which allows checking the encryption policies of two inodes > to ensure they are identical. > > Signed-off-by: Omar Sandoval <osandov@osandov.com> > Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> > --- > fs/crypto/policy.c | 26 ++++++++++++++++++++++++++ > include/linux/fscrypt.h | 7 +++++++ > 2 files changed, 33 insertions(+) > > diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c > index 46757c3052ef..b7c4820a8001 100644 > --- a/fs/crypto/policy.c > +++ b/fs/crypto/policy.c > @@ -415,6 +415,32 @@ static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy) > return fscrypt_policy_from_context(policy, &ctx, ret); > } > > +/** > + * fscrypt_have_same_policy() - check whether two inodes have the same policy > + * @inode1: the first inode > + * @inode2: the second inode > + * > + * Return: %true if they are definitely equal, else %false > + */ > +int fscrypt_have_same_policy(struct inode *inode1, struct inode *inode2) > +{ > + union fscrypt_policy policy1, policy2; > + int err; > + > + if (!IS_ENCRYPTED(inode1) && !IS_ENCRYPTED(inode2)) > + return true; > + else if (!IS_ENCRYPTED(inode1) || !IS_ENCRYPTED(inode2)) > + return false; > + err = fscrypt_get_policy(inode1, &policy1); > + if (err) > + return false; > + err = fscrypt_get_policy(inode2, &policy2); > + if (err) > + return false; Should we bubble up the errors here instead of squashing them down to false? (I noticed this because Josef had another comment about returning int vs bool in this function.) > + return fscrypt_policies_equal(&policy1, &policy2); > +} > +EXPORT_SYMBOL(fscrypt_have_same_policy);
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 46757c3052ef..b7c4820a8001 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -415,6 +415,32 @@ static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy) return fscrypt_policy_from_context(policy, &ctx, ret); } +/** + * fscrypt_have_same_policy() - check whether two inodes have the same policy + * @inode1: the first inode + * @inode2: the second inode + * + * Return: %true if they are definitely equal, else %false + */ +int fscrypt_have_same_policy(struct inode *inode1, struct inode *inode2) +{ + union fscrypt_policy policy1, policy2; + int err; + + if (!IS_ENCRYPTED(inode1) && !IS_ENCRYPTED(inode2)) + return true; + else if (!IS_ENCRYPTED(inode1) || !IS_ENCRYPTED(inode2)) + return false; + err = fscrypt_get_policy(inode1, &policy1); + if (err) + return false; + err = fscrypt_get_policy(inode2, &policy2); + if (err) + return false; + return fscrypt_policies_equal(&policy1, &policy2); +} +EXPORT_SYMBOL(fscrypt_have_same_policy); + static int set_encryption_policy(struct inode *inode, const union fscrypt_policy *policy) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 4cdff7c15544..9cc5a61c1200 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -313,6 +313,7 @@ static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) void fscrypt_free_bounce_page(struct page *bounce_page); /* policy.c */ +int fscrypt_have_same_policy(struct inode *inode1, struct inode *inode2); int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg); int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg); int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg); @@ -490,6 +491,12 @@ static inline void fscrypt_free_bounce_page(struct page *bounce_page) } /* policy.c */ +static inline int fscrypt_have_same_policy(struct inode *inode1, + struct inode *inode2) +{ + return 1; +} + static inline int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg) {