From be6d3e56a6b9b3a4ee44a0685e39e595073c6f0d Mon Sep 17 00:00:00 2001 From: Kentaro Takeda Date: Wed, 17 Dec 2008 13:24:15 +0900 Subject: [PATCH] introduce new LSM hooks where vfsmount is available. Add new LSM hooks for path-based checks. Call them on directory-modifying operations at the points where we still know the vfsmount involved. Signed-off-by: Kentaro Takeda Signed-off-by: Tetsuo Handa Signed-off-by: Toshiharu Harada Signed-off-by: Al Viro --- fs/namei.c | 36 +++++++++++++ fs/open.c | 5 ++ include/linux/security.h | 137 +++++++++++++++++++++++++++++++++++++++++++++++ net/unix/af_unix.c | 4 ++ security/Kconfig | 9 ++++ security/capability.c | 57 ++++++++++++++++++++ security/security.c | 66 +++++++++++++++++++++++ 7 files changed, 314 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index af3783f..ab441af 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1556,6 +1556,9 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) * Refuse to truncate files with mandatory locks held on them. */ error = locks_verify_locked(inode); + if (!error) + error = security_path_truncate(&nd->path, 0, + ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); if (!error) { DQUOT_INIT(inode); @@ -1586,7 +1589,11 @@ static int __open_namei_create(struct nameidata *nd, struct path *path, if (!IS_POSIXACL(dir->d_inode)) mode &= ~current->fs->umask; + error = security_path_mknod(&nd->path, path->dentry, mode, 0); + if (error) + goto out_unlock; error = vfs_create(dir->d_inode, path->dentry, mode, nd); +out_unlock: mutex_unlock(&dir->d_inode->i_mutex); dput(nd->path.dentry); nd->path.dentry = path->dentry; @@ -1999,6 +2006,9 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_mknod(&nd.path, dentry, mode, dev); + if (error) + goto out_drop_write; switch (mode & S_IFMT) { case 0: case S_IFREG: error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); @@ -2011,6 +2021,7 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); break; } +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(dentry); @@ -2070,7 +2081,11 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_mkdir(&nd.path, dentry, mode); + if (error) + goto out_drop_write; error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(dentry); @@ -2180,7 +2195,11 @@ static long do_rmdir(int dfd, const char __user *pathname) error = mnt_want_write(nd.path.mnt); if (error) goto exit3; + error = security_path_rmdir(&nd.path, dentry); + if (error) + goto exit4; error = vfs_rmdir(nd.path.dentry->d_inode, dentry); +exit4: mnt_drop_write(nd.path.mnt); exit3: dput(dentry); @@ -2265,7 +2284,11 @@ static long do_unlinkat(int dfd, const char __user *pathname) error = mnt_want_write(nd.path.mnt); if (error) goto exit2; + error = security_path_unlink(&nd.path, dentry); + if (error) + goto exit3; error = vfs_unlink(nd.path.dentry->d_inode, dentry); +exit3: mnt_drop_write(nd.path.mnt); exit2: dput(dentry); @@ -2346,7 +2369,11 @@ asmlinkage long sys_symlinkat(const char __user *oldname, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_symlink(&nd.path, dentry, from); + if (error) + goto out_drop_write; error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(dentry); @@ -2443,7 +2470,11 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_link(old_path.dentry, &nd.path, new_dentry); + if (error) + goto out_drop_write; error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(new_dentry); @@ -2679,8 +2710,13 @@ asmlinkage long sys_renameat(int olddfd, const char __user *oldname, error = mnt_want_write(oldnd.path.mnt); if (error) goto exit5; + error = security_path_rename(&oldnd.path, old_dentry, + &newnd.path, new_dentry); + if (error) + goto exit6; error = vfs_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, new_dentry); +exit6: mnt_drop_write(oldnd.path.mnt); exit5: dput(new_dentry); diff --git a/fs/open.c b/fs/open.c index c0a426d..1cd7d40 100644 --- a/fs/open.c +++ b/fs/open.c @@ -272,6 +272,8 @@ static long do_sys_truncate(const char __user *pathname, loff_t length) goto put_write_and_out; error = locks_verify_truncate(inode, NULL, length); + if (!error) + error = security_path_truncate(&path, length, 0); if (!error) { DQUOT_INIT(inode); error = do_truncate(path.dentry, length, 0, NULL); @@ -329,6 +331,9 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) error = locks_verify_truncate(inode, file, length); if (!error) + error = security_path_truncate(&file->f_path, length, + ATTR_MTIME|ATTR_CTIME); + if (!error) error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file); out_putf: fput(file); diff --git a/include/linux/security.h b/include/linux/security.h index 3416cb8..b92b5e4 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -335,17 +335,37 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @dir contains the inode structure of the parent directory of the new link. * @new_dentry contains the dentry structure for the new link. * Return 0 if permission is granted. + * @path_link: + * Check permission before creating a new hard link to a file. + * @old_dentry contains the dentry structure for an existing link + * to the file. + * @new_dir contains the path structure of the parent directory of + * the new link. + * @new_dentry contains the dentry structure for the new link. + * Return 0 if permission is granted. * @inode_unlink: * Check the permission to remove a hard link to a file. * @dir contains the inode structure of parent directory of the file. * @dentry contains the dentry structure for file to be unlinked. * Return 0 if permission is granted. + * @path_unlink: + * Check the permission to remove a hard link to a file. + * @dir contains the path structure of parent directory of the file. + * @dentry contains the dentry structure for file to be unlinked. + * Return 0 if permission is granted. * @inode_symlink: * Check the permission to create a symbolic link to a file. * @dir contains the inode structure of parent directory of the symbolic link. * @dentry contains the dentry structure of the symbolic link. * @old_name contains the pathname of file. * Return 0 if permission is granted. + * @path_symlink: + * Check the permission to create a symbolic link to a file. + * @dir contains the path structure of parent directory of + * the symbolic link. + * @dentry contains the dentry structure of the symbolic link. + * @old_name contains the pathname of file. + * Return 0 if permission is granted. * @inode_mkdir: * Check permissions to create a new directory in the existing directory * associated with inode strcture @dir. @@ -353,11 +373,25 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @dentry contains the dentry structure of new directory. * @mode contains the mode of new directory. * Return 0 if permission is granted. + * @path_mkdir: + * Check permissions to create a new directory in the existing directory + * associated with path strcture @path. + * @dir containst the path structure of parent of the directory + * to be created. + * @dentry contains the dentry structure of new directory. + * @mode contains the mode of new directory. + * Return 0 if permission is granted. * @inode_rmdir: * Check the permission to remove a directory. * @dir contains the inode structure of parent of the directory to be removed. * @dentry contains the dentry structure of directory to be removed. * Return 0 if permission is granted. + * @path_rmdir: + * Check the permission to remove a directory. + * @dir contains the path structure of parent of the directory to be + * removed. + * @dentry contains the dentry structure of directory to be removed. + * Return 0 if permission is granted. * @inode_mknod: * Check permissions when creating a special file (or a socket or a fifo * file created via the mknod system call). Note that if mknod operation @@ -368,6 +402,15 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @mode contains the mode of the new file. * @dev contains the device number. * Return 0 if permission is granted. + * @path_mknod: + * Check permissions when creating a file. Note that this hook is called + * even if mknod operation is being done for a regular file. + * @dir contains the path structure of parent of the new file. + * @dentry contains the dentry structure of the new file. + * @mode contains the mode of the new file. + * @dev contains the undecoded device number. Use new_decode_dev() to get + * the decoded device number. + * Return 0 if permission is granted. * @inode_rename: * Check for permission to rename a file or directory. * @old_dir contains the inode structure for parent of the old link. @@ -375,6 +418,13 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @new_dir contains the inode structure for parent of the new link. * @new_dentry contains the dentry structure of the new link. * Return 0 if permission is granted. + * @path_rename: + * Check for permission to rename a file or directory. + * @old_dir contains the path structure for parent of the old link. + * @old_dentry contains the dentry structure of the old link. + * @new_dir contains the path structure for parent of the new link. + * @new_dentry contains the dentry structure of the new link. + * Return 0 if permission is granted. * @inode_readlink: * Check the permission to read the symbolic link. * @dentry contains the dentry structure for the file link. @@ -403,6 +453,12 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @dentry contains the dentry structure for the file. * @attr is the iattr structure containing the new file attributes. * Return 0 if permission is granted. + * @path_truncate: + * Check permission before truncating a file. + * @path contains the path structure for the file. + * @length is the new length of the file. + * @time_attrs is the flags passed to do_truncate(). + * Return 0 if permission is granted. * @inode_getattr: * Check permission before obtaining file attributes. * @mnt is the vfsmount where the dentry was looked up @@ -1331,6 +1387,22 @@ struct security_operations { struct super_block *newsb); int (*sb_parse_opts_str) (char *options, struct security_mnt_opts *opts); +#ifdef CONFIG_SECURITY_PATH + int (*path_unlink) (struct path *dir, struct dentry *dentry); + int (*path_mkdir) (struct path *dir, struct dentry *dentry, int mode); + int (*path_rmdir) (struct path *dir, struct dentry *dentry); + int (*path_mknod) (struct path *dir, struct dentry *dentry, int mode, + unsigned int dev); + int (*path_truncate) (struct path *path, loff_t length, + unsigned int time_attrs); + int (*path_symlink) (struct path *dir, struct dentry *dentry, + const char *old_name); + int (*path_link) (struct dentry *old_dentry, struct path *new_dir, + struct dentry *new_dentry); + int (*path_rename) (struct path *old_dir, struct dentry *old_dentry, + struct path *new_dir, struct dentry *new_dentry); +#endif + int (*inode_alloc_security) (struct inode *inode); void (*inode_free_security) (struct inode *inode); int (*inode_init_security) (struct inode *inode, struct inode *dir, @@ -2705,6 +2777,71 @@ static inline void security_skb_classify_flow(struct sk_buff *skb, struct flowi #endif /* CONFIG_SECURITY_NETWORK_XFRM */ +#ifdef CONFIG_SECURITY_PATH +int security_path_unlink(struct path *dir, struct dentry *dentry); +int security_path_mkdir(struct path *dir, struct dentry *dentry, int mode); +int security_path_rmdir(struct path *dir, struct dentry *dentry); +int security_path_mknod(struct path *dir, struct dentry *dentry, int mode, + unsigned int dev); +int security_path_truncate(struct path *path, loff_t length, + unsigned int time_attrs); +int security_path_symlink(struct path *dir, struct dentry *dentry, + const char *old_name); +int security_path_link(struct dentry *old_dentry, struct path *new_dir, + struct dentry *new_dentry); +int security_path_rename(struct path *old_dir, struct dentry *old_dentry, + struct path *new_dir, struct dentry *new_dentry); +#else /* CONFIG_SECURITY_PATH */ +static inline int security_path_unlink(struct path *dir, struct dentry *dentry) +{ + return 0; +} + +static inline int security_path_mkdir(struct path *dir, struct dentry *dentry, + int mode) +{ + return 0; +} + +static inline int security_path_rmdir(struct path *dir, struct dentry *dentry) +{ + return 0; +} + +static inline int security_path_mknod(struct path *dir, struct dentry *dentry, + int mode, unsigned int dev) +{ + return 0; +} + +static inline int security_path_truncate(struct path *path, loff_t length, + unsigned int time_attrs) +{ + return 0; +} + +static inline int security_path_symlink(struct path *dir, struct dentry *dentry, + const char *old_name) +{ + return 0; +} + +static inline int security_path_link(struct dentry *old_dentry, + struct path *new_dir, + struct dentry *new_dentry) +{ + return 0; +} + +static inline int security_path_rename(struct path *old_dir, + struct dentry *old_dentry, + struct path *new_dir, + struct dentry *new_dentry) +{ + return 0; +} +#endif /* CONFIG_SECURITY_PATH */ + #ifdef CONFIG_KEYS #ifdef CONFIG_SECURITY diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index c6250d0..d1b8982 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -836,7 +836,11 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) err = mnt_want_write(nd.path.mnt); if (err) goto out_mknod_dput; + err = security_path_mknod(&nd.path, dentry, mode, 0); + if (err) + goto out_mknod_drop_write; err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0); +out_mknod_drop_write: mnt_drop_write(nd.path.mnt); if (err) goto out_mknod_dput; diff --git a/security/Kconfig b/security/Kconfig index d9f47ce..9438535 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -81,6 +81,15 @@ config SECURITY_NETWORK_XFRM IPSec. If you are unsure how to answer this question, answer N. +config SECURITY_PATH + bool "Security hooks for pathname based access control" + depends on SECURITY + help + This enables the security hooks for pathname based access control. + If enabled, a security module can use these hooks to + implement pathname based access controls. + If you are unsure how to answer this question, answer N. + config SECURITY_FILE_CAPABILITIES bool "File POSIX Capabilities" default n diff --git a/security/capability.c b/security/capability.c index 2dce66f..c545bd1 100644 --- a/security/capability.c +++ b/security/capability.c @@ -263,6 +263,53 @@ static void cap_inode_getsecid(const struct inode *inode, u32 *secid) *secid = 0; } +#ifdef CONFIG_SECURITY_PATH +static int cap_path_mknod(struct path *dir, struct dentry *dentry, int mode, + unsigned int dev) +{ + return 0; +} + +static int cap_path_mkdir(struct path *dir, struct dentry *dentry, int mode) +{ + return 0; +} + +static int cap_path_rmdir(struct path *dir, struct dentry *dentry) +{ + return 0; +} + +static int cap_path_unlink(struct path *dir, struct dentry *dentry) +{ + return 0; +} + +static int cap_path_symlink(struct path *dir, struct dentry *dentry, + const char *old_name) +{ + return 0; +} + +static int cap_path_link(struct dentry *old_dentry, struct path *new_dir, + struct dentry *new_dentry) +{ + return 0; +} + +static int cap_path_rename(struct path *old_path, struct dentry *old_dentry, + struct path *new_path, struct dentry *new_dentry) +{ + return 0; +} + +static int cap_path_truncate(struct path *path, loff_t length, + unsigned int time_attrs) +{ + return 0; +} +#endif + static int cap_file_permission(struct file *file, int mask) { return 0; @@ -883,6 +930,16 @@ void security_fixup_ops(struct security_operations *ops) set_to_cap_if_null(ops, inode_setsecurity); set_to_cap_if_null(ops, inode_listsecurity); set_to_cap_if_null(ops, inode_getsecid); +#ifdef CONFIG_SECURITY_PATH + set_to_cap_if_null(ops, path_mknod); + set_to_cap_if_null(ops, path_mkdir); + set_to_cap_if_null(ops, path_rmdir); + set_to_cap_if_null(ops, path_unlink); + set_to_cap_if_null(ops, path_symlink); + set_to_cap_if_null(ops, path_link); + set_to_cap_if_null(ops, path_rename); + set_to_cap_if_null(ops, path_truncate); +#endif set_to_cap_if_null(ops, file_permission); set_to_cap_if_null(ops, file_alloc_security); set_to_cap_if_null(ops, file_free_security); diff --git a/security/security.c b/security/security.c index d85dbb3..678d4d0 100644 --- a/security/security.c +++ b/security/security.c @@ -355,6 +355,72 @@ int security_inode_init_security(struct inode *inode, struct inode *dir, } EXPORT_SYMBOL(security_inode_init_security); +#ifdef CONFIG_SECURITY_PATH +int security_path_mknod(struct path *path, struct dentry *dentry, int mode, + unsigned int dev) +{ + if (unlikely(IS_PRIVATE(path->dentry->d_inode))) + return 0; + return security_ops->path_mknod(path, dentry, mode, dev); +} +EXPORT_SYMBOL(security_path_mknod); + +int security_path_mkdir(struct path *path, struct dentry *dentry, int mode) +{ + if (unlikely(IS_PRIVATE(path->dentry->d_inode))) + return 0; + return security_ops->path_mkdir(path, dentry, mode); +} + +int security_path_rmdir(struct path *path, struct dentry *dentry) +{ + if (unlikely(IS_PRIVATE(path->dentry->d_inode))) + return 0; + return security_ops->path_rmdir(path, dentry); +} + +int security_path_unlink(struct path *path, struct dentry *dentry) +{ + if (unlikely(IS_PRIVATE(path->dentry->d_inode))) + return 0; + return security_ops->path_unlink(path, dentry); +} + +int security_path_symlink(struct path *path, struct dentry *dentry, + const char *old_name) +{ + if (unlikely(IS_PRIVATE(path->dentry->d_inode))) + return 0; + return security_ops->path_symlink(path, dentry, old_name); +} + +int security_path_link(struct dentry *old_dentry, struct path *new_dir, + struct dentry *new_dentry) +{ + if (unlikely(IS_PRIVATE(old_dentry->d_inode))) + return 0; + return security_ops->path_link(old_dentry, new_dir, new_dentry); +} + +int security_path_rename(struct path *old_dir, struct dentry *old_dentry, + struct path *new_dir, struct dentry *new_dentry) +{ + if (unlikely(IS_PRIVATE(old_dentry->d_inode) || + (new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode)))) + return 0; + return security_ops->path_rename(old_dir, old_dentry, new_dir, + new_dentry); +} + +int security_path_truncate(struct path *path, loff_t length, + unsigned int time_attrs) +{ + if (unlikely(IS_PRIVATE(path->dentry->d_inode))) + return 0; + return security_ops->path_truncate(path, length, time_attrs); +} +#endif + int security_inode_create(struct inode *dir, struct dentry *dentry, int mode) { if (unlikely(IS_PRIVATE(dir))) -- 1.8.2.3