From f424f664f0e8949361d268e2e91c7acc8cf63eb2 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Mon, 20 Apr 2015 15:19:06 -0700 Subject: [PATCH] f2fs crypto: add encryption policy and password salt support This patch adds encryption policy and password salt support through ioctl implementation. It adds three ioctls: F2FS_IOC_SET_ENCRYPTION_POLICY, F2FS_IOC_GET_ENCRYPTION_POLICY, F2FS_IOC_GET_ENCRYPTION_PWSALT, which use xattr operations. Note that, these definition and codes are taken from ext4 crypto support. For f2fs, xattr operations and on-disk flags for superblock and inode were changed. Signed-off-by: Michael Halcrow Signed-off-by: Theodore Ts'o Signed-off-by: Ildar Muslukhov Signed-off-by: Jaegeuk Kim --- fs/f2fs/Makefile | 1 + fs/f2fs/crypto_policy.c | 206 ++++++++++++++++++++++++++++++++++++++++ fs/f2fs/f2fs.h | 16 ++++ fs/f2fs/file.c | 93 ++++++++++++++++++ fs/f2fs/xattr.c | 3 + 5 files changed, 319 insertions(+) create mode 100644 fs/f2fs/crypto_policy.c diff --git a/fs/f2fs/Makefile b/fs/f2fs/Makefile index d92397731db8..7864f4f02ca6 100644 --- a/fs/f2fs/Makefile +++ b/fs/f2fs/Makefile @@ -6,3 +6,4 @@ f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o f2fs-$(CONFIG_F2FS_IO_TRACE) += trace.o +f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o diff --git a/fs/f2fs/crypto_policy.c b/fs/f2fs/crypto_policy.c new file mode 100644 index 000000000000..bef254b21815 --- /dev/null +++ b/fs/f2fs/crypto_policy.c @@ -0,0 +1,206 @@ +/* + * copied from linux/fs/ext4/crypto_policy.c + * + * Copyright (C) 2015, Google, Inc. + * Copyright (C) 2015, Motorola Mobility. + * + * This contains encryption policy functions for f2fs with some modifications + * to support f2fs-specific xattr APIs. + * + * Written by Michael Halcrow, 2015. + * Modified by Jaegeuk Kim, 2015. + */ +#include +#include +#include +#include + +#include "f2fs.h" +#include "xattr.h" + +static int f2fs_inode_has_encryption_context(struct inode *inode) +{ + int res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION, + F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, NULL, 0, NULL); + return (res > 0); +} + +/* + * check whether the policy is consistent with the encryption context + * for the inode + */ +static int f2fs_is_encryption_context_consistent_with_policy( + struct inode *inode, const struct f2fs_encryption_policy *policy) +{ + struct f2fs_encryption_context ctx; + int res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION, + F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx, + sizeof(ctx), NULL); + + if (res != sizeof(ctx)) + return 0; + + return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor, + F2FS_KEY_DESCRIPTOR_SIZE) == 0 && + (ctx.flags == policy->flags) && + (ctx.contents_encryption_mode == + policy->contents_encryption_mode) && + (ctx.filenames_encryption_mode == + policy->filenames_encryption_mode)); +} + +static int f2fs_create_encryption_context_from_policy( + struct inode *inode, const struct f2fs_encryption_policy *policy) +{ + struct f2fs_encryption_context ctx; + + ctx.format = F2FS_ENCRYPTION_CONTEXT_FORMAT_V1; + memcpy(ctx.master_key_descriptor, policy->master_key_descriptor, + F2FS_KEY_DESCRIPTOR_SIZE); + + if (!f2fs_valid_contents_enc_mode(policy->contents_encryption_mode)) { + printk(KERN_WARNING + "%s: Invalid contents encryption mode %d\n", __func__, + policy->contents_encryption_mode); + return -EINVAL; + } + + if (!f2fs_valid_filenames_enc_mode(policy->filenames_encryption_mode)) { + printk(KERN_WARNING + "%s: Invalid filenames encryption mode %d\n", __func__, + policy->filenames_encryption_mode); + return -EINVAL; + } + + if (policy->flags & ~F2FS_POLICY_FLAGS_VALID) + return -EINVAL; + + ctx.contents_encryption_mode = policy->contents_encryption_mode; + ctx.filenames_encryption_mode = policy->filenames_encryption_mode; + ctx.flags = policy->flags; + BUILD_BUG_ON(sizeof(ctx.nonce) != F2FS_KEY_DERIVATION_NONCE_SIZE); + get_random_bytes(ctx.nonce, F2FS_KEY_DERIVATION_NONCE_SIZE); + + return f2fs_setxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION, + F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx, + sizeof(ctx), NULL, 0); +} + +int f2fs_process_policy(const struct f2fs_encryption_policy *policy, + struct inode *inode) +{ + if (policy->version != 0) + return -EINVAL; + + if (!f2fs_inode_has_encryption_context(inode)) { + if (!f2fs_empty_dir(inode)) + return -ENOTEMPTY; + return f2fs_create_encryption_context_from_policy(inode, + policy); + } + + if (f2fs_is_encryption_context_consistent_with_policy(inode, policy)) + return 0; + + printk(KERN_WARNING "%s: Policy inconsistent with encryption context\n", + __func__); + return -EINVAL; +} + +int f2fs_get_policy(struct inode *inode, struct f2fs_encryption_policy *policy) +{ + struct f2fs_encryption_context ctx; + int res; + + if (!f2fs_encrypted_inode(inode)) + return -ENODATA; + + res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION, + F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, + &ctx, sizeof(ctx), NULL); + if (res != sizeof(ctx)) + return -ENODATA; + if (ctx.format != F2FS_ENCRYPTION_CONTEXT_FORMAT_V1) + return -EINVAL; + + policy->version = 0; + policy->contents_encryption_mode = ctx.contents_encryption_mode; + policy->filenames_encryption_mode = ctx.filenames_encryption_mode; + policy->flags = ctx.flags; + memcpy(&policy->master_key_descriptor, ctx.master_key_descriptor, + F2FS_KEY_DESCRIPTOR_SIZE); + return 0; +} + +int f2fs_is_child_context_consistent_with_parent(struct inode *parent, + struct inode *child) +{ + struct f2fs_crypt_info *parent_ci, *child_ci; + int res; + + if ((parent == NULL) || (child == NULL)) { + pr_err("parent %p child %p\n", parent, child); + BUG_ON(1); + } + + /* no restrictions if the parent directory is not encrypted */ + if (!f2fs_encrypted_inode(parent)) + return 1; + /* if the child directory is not encrypted, this is always a problem */ + if (!f2fs_encrypted_inode(child)) + return 0; + res = f2fs_get_encryption_info(parent); + if (res) + return 0; + res = f2fs_get_encryption_info(child); + if (res) + return 0; + parent_ci = F2FS_I(parent)->i_crypt_info; + child_ci = F2FS_I(child)->i_crypt_info; + if (!parent_ci && !child_ci) + return 1; + if (!parent_ci || !child_ci) + return 0; + + return (memcmp(parent_ci->ci_master_key, + child_ci->ci_master_key, + F2FS_KEY_DESCRIPTOR_SIZE) == 0 && + (parent_ci->ci_data_mode == child_ci->ci_data_mode) && + (parent_ci->ci_filename_mode == child_ci->ci_filename_mode) && + (parent_ci->ci_flags == child_ci->ci_flags)); +} + +/** + * f2fs_inherit_context() - Sets a child context from its parent + * @parent: Parent inode from which the context is inherited. + * @child: Child inode that inherits the context from @parent. + * + * Return: Zero on success, non-zero otherwise + */ +int f2fs_inherit_context(struct inode *parent, struct inode *child, + struct page *ipage) +{ + struct f2fs_encryption_context ctx; + struct f2fs_crypt_info *ci; + int res; + + res = f2fs_get_encryption_info(parent); + if (res < 0) + return res; + + ci = F2FS_I(parent)->i_crypt_info; + BUG_ON(ci == NULL); + + ctx.format = F2FS_ENCRYPTION_CONTEXT_FORMAT_V1; + + ctx.contents_encryption_mode = ci->ci_data_mode; + ctx.filenames_encryption_mode = ci->ci_filename_mode; + ctx.flags = ci->ci_flags; + memcpy(ctx.master_key_descriptor, ci->ci_master_key, + F2FS_KEY_DESCRIPTOR_SIZE); + + get_random_bytes(ctx.nonce, F2FS_KEY_DERIVATION_NONCE_SIZE); + return f2fs_setxattr(child, F2FS_XATTR_INDEX_ENCRYPTION, + F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx, + sizeof(ctx), ipage, 0); +} diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 2c2948fbc35f..709660bd926a 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -229,6 +229,13 @@ static inline bool __has_cursum_space(struct f2fs_summary_block *sum, int size, #define F2FS_IOC_RELEASE_VOLATILE_WRITE _IO(F2FS_IOCTL_MAGIC, 4) #define F2FS_IOC_ABORT_VOLATILE_WRITE _IO(F2FS_IOCTL_MAGIC, 5) +#define F2FS_IOC_SET_ENCRYPTION_POLICY \ + _IOR('f', 19, struct f2fs_encryption_policy) +#define F2FS_IOC_GET_ENCRYPTION_PWSALT \ + _IOW('f', 20, __u8[16]) +#define F2FS_IOC_GET_ENCRYPTION_POLICY \ + _IOW('f', 21, struct f2fs_encryption_policy) + /* * should be same as XFS_IOC_GOINGDOWN. * Flags for going down operation used by FS_IOC_GOINGDOWN @@ -367,6 +374,8 @@ struct f2fs_map_blocks { #define F2FS_ENCRYPTION_MODE_AES_256_CBC 3 #define F2FS_ENCRYPTION_MODE_AES_256_CTS 4 +#include "f2fs_crypto.h" + #define DEF_DIR_LEVEL 0 struct f2fs_inode_info { @@ -1946,4 +1955,11 @@ static inline int f2fs_sb_has_crypto(struct super_block *sb) return 0; #endif } + +/* crypto_policy.c */ +int f2fs_is_child_context_consistent_with_parent(struct inode *, + struct inode *); +int f2fs_inherit_context(struct inode *, struct inode *, struct page *); +int f2fs_process_policy(const struct f2fs_encryption_policy *, struct inode *); +int f2fs_get_policy(struct inode *, struct f2fs_encryption_policy *); #endif diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 7293746f1fe6..a66970d99cb4 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "f2fs.h" #include "node.h" @@ -1347,6 +1348,92 @@ static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg) return 0; } +static bool uuid_is_nonzero(__u8 u[16]) +{ + int i; + + for (i = 0; i < 16; i++) + if (u[i]) + return true; + return false; +} + +static int f2fs_ioc_set_encryption_policy(struct file *filp, unsigned long arg) +{ +#ifdef CONFIG_F2FS_FS_ENCRYPTION + struct f2fs_encryption_policy policy; + struct inode *inode = file_inode(filp); + + if (copy_from_user(&policy, (struct f2fs_encryption_policy __user *)arg, + sizeof(policy))) + return -EFAULT; + + if (f2fs_has_inline_data(inode)) { + int ret = f2fs_convert_inline_inode(inode); + if (ret) + return ret; + } + + return f2fs_process_policy(&policy, inode); +#else + return -EOPNOTSUPP; +#endif +} + +static int f2fs_ioc_get_encryption_policy(struct file *filp, unsigned long arg) +{ +#ifdef CONFIG_F2FS_FS_ENCRYPTION + struct f2fs_encryption_policy policy; + struct inode *inode = file_inode(filp); + int err; + + err = f2fs_get_policy(inode, &policy); + if (err) + return err; + + if (copy_to_user((struct f2fs_encryption_policy __user *)arg, &policy, + sizeof(policy))) + return -EFAULT; + return 0; +#else + return -EOPNOTSUPP; +#endif +} + +static int f2fs_ioc_get_encryption_pwsalt(struct file *filp, unsigned long arg) +{ + struct inode *inode = file_inode(filp); + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); + int err; + + if (!f2fs_sb_has_crypto(inode->i_sb)) + return -EOPNOTSUPP; + + if (uuid_is_nonzero(sbi->raw_super->encrypt_pw_salt)) + goto got_it; + + err = mnt_want_write_file(filp); + if (err) + return err; + + /* update superblock with uuid */ + generate_random_uuid(sbi->raw_super->encrypt_pw_salt); + + err = f2fs_commit_super(sbi); + + mnt_drop_write_file(filp); + if (err) { + /* undo new data */ + memset(sbi->raw_super->encrypt_pw_salt, 0, 16); + return err; + } +got_it: + if (copy_to_user((__u8 __user *)arg, sbi->raw_super->encrypt_pw_salt, + 16)) + return -EFAULT; + return 0; +} + long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { switch (cmd) { @@ -1370,6 +1457,12 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return f2fs_ioc_shutdown(filp, arg); case FITRIM: return f2fs_ioc_fitrim(filp, arg); + case F2FS_IOC_SET_ENCRYPTION_POLICY: + return f2fs_ioc_set_encryption_policy(filp, arg); + case F2FS_IOC_GET_ENCRYPTION_POLICY: + return f2fs_ioc_get_encryption_policy(filp, arg); + case F2FS_IOC_GET_ENCRYPTION_PWSALT: + return f2fs_ioc_get_encryption_pwsalt(filp, arg); default: return -ENOTTY; } diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index 9757f65a05bc..07449b980acb 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -584,6 +584,9 @@ static int __f2fs_setxattr(struct inode *inode, int index, inode->i_ctime = CURRENT_TIME; clear_inode_flag(fi, FI_ACL_MODE); } + if (index == F2FS_XATTR_INDEX_ENCRYPTION && + !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT)) + f2fs_set_encrypted_inode(inode); if (ipage) update_inode(inode, ipage); -- 2.20.1