| Message ID | 20200107023323.38394-3-drosen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fscrypt support for casefolded encryption | expand |
On Mon, Jan 06, 2020 at 06:33:22PM -0800, Daniel Rosenberg wrote: > Casefolding currently requires a derived key for computing the siphash. > This is available for v2 policies, but not v1, so we disallow it for v1. > > Signed-off-by: Daniel Rosenberg <drosen@google.com> > --- > fs/crypto/keysetup.c | 7 ++++--- > fs/crypto/policy.c | 39 +++++++++++++++++++++++++++++++++++++++ > fs/inode.c | 7 +++++++ > include/linux/fscrypt.h | 11 +++++++++++ > 4 files changed, 61 insertions(+), 3 deletions(-) > > diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c > index c1bd897c9310..7445ab76e0b3 100644 > --- a/fs/crypto/keysetup.c > +++ b/fs/crypto/keysetup.c > @@ -224,10 +224,11 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, > FS_KEY_DERIVATION_NONCE_SIZE, > (u8 *)&ci->ci_hash_key, > sizeof(ci->ci_hash_key)); > - if (!err) > - ci->ci_hash_key_initialized = true; > + if (err) > + return err; > + ci->ci_hash_key_initialized = true; > } > - return err; > + return 0; > } This part should be folded into patch 1. > > /* > diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c > index f1cff83c151a..9e937cfa732c 100644 > --- a/fs/crypto/policy.c > +++ b/fs/crypto/policy.c > @@ -124,6 +124,12 @@ static bool fscrypt_supported_v1_policy(const struct fscrypt_policy_v1 *policy, > policy->filenames_encryption_mode)) > return false; > > + if (IS_CASEFOLDED(inode)) { > + fscrypt_warn(inode, > + "v1 policy does not support casefolded directories"); > + return false; > + } > + > return true; > } > > @@ -579,3 +585,36 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child, > return preload ? fscrypt_get_encryption_info(child): 0; > } > EXPORT_SYMBOL(fscrypt_inherit_context); > + > +static int fscrypt_set_casefolding_allowed(struct inode *inode) > +{ > + union fscrypt_policy policy; > + int err = fscrypt_get_policy(inode, &policy); > + > + if (err) > + return err; > + > + if (policy.version != FSCRYPT_POLICY_V2) > + return -EINVAL; > + > + return 0; > +} > + > +int fscrypt_ioc_setflags_prepare(struct inode *inode, > + unsigned int oldflags, > + unsigned int flags) > +{ > + int err; > + > + /* > + * When a directory is encrypted, the CASEFOLD flag can only be turned > + * on if the fscrypt policy supports it. > + */ > + if (IS_ENCRYPTED(inode) && (flags & ~oldflags & FS_CASEFOLD_FL)) { > + err = fscrypt_set_casefolding_allowed(inode); > + if (err) > + return err; > + } > + > + return 0; > +} There's not really any point to the fscrypt_set_casefolding_allowed() function. It can just be folded into fscrypt_ioc_setflags_prepare(): int fscrypt_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, unsigned int flags) { union fscrypt_policy policy; int err; /* * When a directory is encrypted, the CASEFOLD flag can only be turned * on if the fscrypt policy supports it. */ if (IS_ENCRYPTED(inode) && (flags & ~oldflags & FS_CASEFOLD_FL)) { err = fscrypt_get_policy(inode, &policy); if (err) return err; if (policy.version != FSCRYPT_POLICY_V2) return -EINVAL; } return 0; } > @@ -2242,6 +2243,8 @@ EXPORT_SYMBOL(current_time); > int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, > unsigned int flags) > { > + int err; > + > /* > * The IMMUTABLE and APPEND_ONLY flags can only be changed by > * the relevant capability. > @@ -2252,6 +2255,10 @@ int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, > !capable(CAP_LINUX_IMMUTABLE)) > return -EPERM; > > + err = fscrypt_ioc_setflags_prepare(inode, oldflags, flags); > + if (err) > + return err; > + > return 0; > } Can just do 'return fscrypt_ioc_setflags_prepare(inode, oldflags, flags);' - Eric
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index c1bd897c9310..7445ab76e0b3 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -224,10 +224,11 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, FS_KEY_DERIVATION_NONCE_SIZE, (u8 *)&ci->ci_hash_key, sizeof(ci->ci_hash_key)); - if (!err) - ci->ci_hash_key_initialized = true; + if (err) + return err; + ci->ci_hash_key_initialized = true; } - return err; + return 0; } /* diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index f1cff83c151a..9e937cfa732c 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -124,6 +124,12 @@ static bool fscrypt_supported_v1_policy(const struct fscrypt_policy_v1 *policy, policy->filenames_encryption_mode)) return false; + if (IS_CASEFOLDED(inode)) { + fscrypt_warn(inode, + "v1 policy does not support casefolded directories"); + return false; + } + return true; } @@ -579,3 +585,36 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child, return preload ? fscrypt_get_encryption_info(child): 0; } EXPORT_SYMBOL(fscrypt_inherit_context); + +static int fscrypt_set_casefolding_allowed(struct inode *inode) +{ + union fscrypt_policy policy; + int err = fscrypt_get_policy(inode, &policy); + + if (err) + return err; + + if (policy.version != FSCRYPT_POLICY_V2) + return -EINVAL; + + return 0; +} + +int fscrypt_ioc_setflags_prepare(struct inode *inode, + unsigned int oldflags, + unsigned int flags) +{ + int err; + + /* + * When a directory is encrypted, the CASEFOLD flag can only be turned + * on if the fscrypt policy supports it. + */ + if (IS_ENCRYPTED(inode) && (flags & ~oldflags & FS_CASEFOLD_FL)) { + err = fscrypt_set_casefolding_allowed(inode); + if (err) + return err; + } + + return 0; +} diff --git a/fs/inode.c b/fs/inode.c index 96d62d97694e..77f3e6e2e934 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -20,6 +20,7 @@ #include <linux/ratelimit.h> #include <linux/list_lru.h> #include <linux/iversion.h> +#include <linux/fscrypt.h> #include <trace/events/writeback.h> #include "internal.h" @@ -2242,6 +2243,8 @@ EXPORT_SYMBOL(current_time); int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, unsigned int flags) { + int err; + /* * The IMMUTABLE and APPEND_ONLY flags can only be changed by * the relevant capability. @@ -2252,6 +2255,10 @@ int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, !capable(CAP_LINUX_IMMUTABLE)) return -EPERM; + err = fscrypt_ioc_setflags_prepare(inode, oldflags, flags); + if (err) + return err; + return 0; } EXPORT_SYMBOL(vfs_ioc_setflags_prepare); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 1dfbed855bee..2c292f19c6b9 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -142,6 +142,10 @@ extern int fscrypt_ioctl_get_policy_ex(struct file *, void __user *); extern int fscrypt_has_permitted_context(struct inode *, struct inode *); extern int fscrypt_inherit_context(struct inode *, struct inode *, void *, bool); +extern int fscrypt_ioc_setflags_prepare(struct inode *inode, + unsigned int oldflags, + unsigned int flags); + /* keyring.c */ extern void fscrypt_sb_free(struct super_block *sb); extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg); @@ -383,6 +387,13 @@ static inline int fscrypt_inherit_context(struct inode *parent, return -EOPNOTSUPP; } +static inline int fscrypt_ioc_setflags_prepare(struct inode *inode, + unsigned int oldflags, + unsigned int flags) +{ + return 0; +} + /* keyring.c */ static inline void fscrypt_sb_free(struct super_block *sb) {
Casefolding currently requires a derived key for computing the siphash. This is available for v2 policies, but not v1, so we disallow it for v1. Signed-off-by: Daniel Rosenberg <drosen@google.com> --- fs/crypto/keysetup.c | 7 ++++--- fs/crypto/policy.c | 39 +++++++++++++++++++++++++++++++++++++++ fs/inode.c | 7 +++++++ include/linux/fscrypt.h | 11 +++++++++++ 4 files changed, 61 insertions(+), 3 deletions(-)