f2fs: support access control via key management

Message ID	1457571168-56724-1-git-send-email-jaegeuk@kernel.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-fsdevel-owner@kernel.org> From: Jaegeuk Kim <jaegeuk@kernel.org> To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Jaegeuk Kim <jaegeuk@kernel.org> Subject: [PATCH] f2fs: support access control via key management Date: Wed, 9 Mar 2016 16:52:48 -0800 Message-Id: <1457571168-56724-1-git-send-email-jaegeuk@kernel.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index bbe2cd1..cbc115b 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -212,6 +212,8 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal, #define F2FS_IOC_WRITE_CHECKPOINT _IO(F2FS_IOCTL_MAGIC, 7) #define F2FS_IOC_DEFRAGMENT _IO(F2FS_IOCTL_MAGIC, 8) +#define F2FS_IOC_KEYCTL _IOW(F2FS_IOCTL_MAGIC, 9, struct f2fs_key) + #define F2FS_IOC_SET_ENCRYPTION_POLICY FS_IOC_SET_ENCRYPTION_POLICY #define F2FS_IOC_GET_ENCRYPTION_POLICY FS_IOC_GET_ENCRYPTION_POLICY #define F2FS_IOC_GET_ENCRYPTION_PWSALT FS_IOC_GET_ENCRYPTION_PWSALT @@ -235,6 +237,20 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal, #define F2FS_IOC32_GETVERSION FS_IOC32_GETVERSION #endif +#define F2FS_KEY_SIZE 8 +#define F2FS_KEY_DESC_PREFIX "f2fs:" +#define F2FS_KEY_DESC_PREFIX_SIZE 5 + +enum f2fs_key_mode { + F2FS_SET_KEY, + F2FS_DROP_KEY, +}; + +struct f2fs_key { + u8 key[F2FS_KEY_SIZE]; + u8 mode; +}; + struct f2fs_defragment { u64 start; u64 len; @@ -358,6 +374,7 @@ struct f2fs_map_blocks { #define FADVISE_LOST_PINO_BIT 0x02 #define FADVISE_ENCRYPT_BIT 0x04 #define FADVISE_ENC_NAME_BIT 0x08 +#define FADVISE_KEY_BIT 0x10 #define file_is_cold(inode) is_file(inode, FADVISE_COLD_BIT) #define file_wrong_pino(inode) is_file(inode, FADVISE_LOST_PINO_BIT) @@ -370,6 +387,9 @@ struct f2fs_map_blocks { #define file_clear_encrypt(inode) clear_file(inode, FADVISE_ENCRYPT_BIT) #define file_enc_name(inode) is_file(inode, FADVISE_ENC_NAME_BIT) #define file_set_enc_name(inode) set_file(inode, FADVISE_ENC_NAME_BIT) +#define file_has_key(inode) is_file(inode, FADVISE_KEY_BIT) +#define file_set_key(inode) set_file(inode, FADVISE_KEY_BIT) +#define file_clear_key(inode) clear_file(inode, FADVISE_KEY_BIT) #define DEF_DIR_LEVEL 0 diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index b41c357..80f6b29 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -21,6 +21,7 @@ #include <linux/mount.h> #include <linux/pagevec.h> #include <linux/random.h> +#include <keys/user-type.h> #include "f2fs.h" #include "node.h" @@ -438,6 +439,40 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma) return 0; } +static int validate_access_key(struct inode *inode) +{ + u8 full_key_descriptor[F2FS_KEY_DESC_PREFIX_SIZE + + (F2FS_KEY_SIZE * 2) + 1]; + struct key *keyring_key = NULL; + u8 key[F2FS_KEY_SIZE]; + int ret; + + ret = f2fs_getxattr(inode, F2FS_XATTR_INDEX_KEY, + F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, + key, F2FS_KEY_SIZE, NULL); + if (ret != F2FS_KEY_SIZE) + return -EINVAL; + + memcpy(full_key_descriptor, F2FS_KEY_DESC_PREFIX, + F2FS_KEY_DESC_PREFIX_SIZE); + sprintf(full_key_descriptor + F2FS_KEY_DESC_PREFIX_SIZE, + "%*phN", F2FS_KEY_SIZE, key); + full_key_descriptor[F2FS_KEY_DESC_PREFIX_SIZE + + (2 * F2FS_KEY_SIZE)] = '\0'; + keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL); + if (IS_ERR(keyring_key)) + return PTR_ERR(keyring_key); + + if (keyring_key->type != &key_type_logon) { + printk_once(KERN_WARNING + "%s: key type must be logon\n", __func__); + key_put(keyring_key); + return -ENOKEY; + } + key_put(keyring_key); + return 0; +} + static int f2fs_file_open(struct inode *inode, struct file *filp) { int ret = generic_file_open(inode, filp); @@ -453,6 +488,9 @@ static int f2fs_file_open(struct inode *inode, struct file *filp) if (f2fs_encrypted_inode(dir) && !fscrypt_has_permitted_context(dir, inode)) return -EPERM; + + if (file_has_key(inode)) + return validate_access_key(inode); return ret; } @@ -1532,6 +1570,35 @@ static bool uuid_is_nonzero(__u8 u[16]) return false; } +static int f2fs_ioc_keyctl(struct file *filp, unsigned long arg) +{ + struct inode *inode = file_inode(filp); + struct f2fs_key key; + void *value = key.key; + int type = XATTR_CREATE; + + if (copy_from_user(&key, (u8 __user *)arg, sizeof(key))) + return -EFAULT; + + if (!S_ISREG(inode->i_mode)) + return -EINVAL; + + if (key.mode == F2FS_DROP_KEY) { + int ret = validate_access_key(inode); + + if (ret) + return ret; + + value = NULL; + type = XATTR_REPLACE; + } + + f2fs_update_time(F2FS_I_SB(inode), REQ_TIME); + return f2fs_setxattr(inode, F2FS_XATTR_INDEX_KEY, + F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, + value, F2FS_KEY_SIZE, NULL, type); +} + static int f2fs_ioc_set_encryption_policy(struct file *filp, unsigned long arg) { struct fscrypt_policy policy; @@ -1845,6 +1912,8 @@ 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_KEYCTL: + return f2fs_ioc_keyctl(filp, arg); case F2FS_IOC_SET_ENCRYPTION_POLICY: return f2fs_ioc_set_encryption_policy(filp, arg); case F2FS_IOC_GET_ENCRYPTION_POLICY: diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index 06a72dc..5b02b31 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -550,6 +550,13 @@ static int __f2fs_setxattr(struct inode *inode, int index, if (index == F2FS_XATTR_INDEX_ENCRYPTION && !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT)) f2fs_set_encrypted_inode(inode); + if (index == F2FS_XATTR_INDEX_KEY && + !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT)) { + if (value) + file_set_key(inode); + else + file_clear_key(inode); + } if (ipage) update_inode(inode, ipage); diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h index 79dccc8..cb5282c 100644 --- a/fs/f2fs/xattr.h +++ b/fs/f2fs/xattr.h @@ -37,6 +37,7 @@ #define F2FS_XATTR_INDEX_ADVISE 7 /* Should be same as EXT4_XATTR_INDEX_ENCRYPTION */ #define F2FS_XATTR_INDEX_ENCRYPTION 9 +#define F2FS_XATTR_INDEX_KEY 10 #define F2FS_XATTR_NAME_ENCRYPTION_CONTEXT "c"

f2fs: support access control via key management

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