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/* |
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* security/ccsecurity/mount.c |
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* |
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* Copyright (C) 2005-2010 NTT DATA CORPORATION |
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* |
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* Version: 1.8.0-pre 2010/08/01 |
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* |
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* This file is applicable to both 2.4.30 and 2.6.11 and later. |
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* See README.ccs for ChangeLog. |
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* |
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*/ |
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|
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#include <linux/slab.h> |
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#include <linux/version.h> |
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 0) |
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#include <linux/dcache.h> |
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#include <linux/namei.h> |
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#endif |
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 20) |
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#include <linux/namespace.h> |
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#endif |
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#include "internal.h" |
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|
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 15) |
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#define MS_UNBINDABLE (1<<17) /* change to unbindable */ |
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#define MS_PRIVATE (1<<18) /* change to private */ |
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#define MS_SLAVE (1<<19) /* change to slave */ |
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#define MS_SHARED (1<<20) /* change to shared */ |
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#endif |
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|
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/* Keywords for mount restrictions. */ |
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|
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/* Allow to call 'mount --bind /source_dir /dest_dir' */ |
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#define CCS_MOUNT_BIND_KEYWORD "--bind" |
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/* Allow to call 'mount --move /old_dir /new_dir ' */ |
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#define CCS_MOUNT_MOVE_KEYWORD "--move" |
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/* Allow to call 'mount -o remount /dir ' */ |
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#define CCS_MOUNT_REMOUNT_KEYWORD "--remount" |
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/* Allow to call 'mount --make-unbindable /dir' */ |
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#define CCS_MOUNT_MAKE_UNBINDABLE_KEYWORD "--make-unbindable" |
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/* Allow to call 'mount --make-private /dir' */ |
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#define CCS_MOUNT_MAKE_PRIVATE_KEYWORD "--make-private" |
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/* Allow to call 'mount --make-slave /dir' */ |
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#define CCS_MOUNT_MAKE_SLAVE_KEYWORD "--make-slave" |
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/* Allow to call 'mount --make-shared /dir' */ |
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#define CCS_MOUNT_MAKE_SHARED_KEYWORD "--make-shared" |
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|
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/** |
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* ccs_audit_mount_log - Audit mount log. |
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* |
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* @r: Pointer to "struct ccs_request_info". |
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* |
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* Returns 0 on success, negative value otherwise. |
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*/ |
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static int ccs_audit_mount_log(struct ccs_request_info *r) |
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{ |
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const char *dev = r->param.mount.dev->name; |
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const char *dir = r->param.mount.dir->name; |
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const char *type = r->param.mount.type->name; |
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const unsigned long flags = r->param.mount.flags; |
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ccs_write_log(r, "file mount %s %s %s 0x%lX\n", dev, dir, type, flags); |
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if (r->granted) |
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return 0; |
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if (!strcmp(type, CCS_MOUNT_REMOUNT_KEYWORD)) |
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ccs_warn_log(r, "file mount -o remount %s 0x%lX", dir, flags); |
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else if (!strcmp(type, CCS_MOUNT_BIND_KEYWORD) |
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|| !strcmp(type, CCS_MOUNT_MOVE_KEYWORD)) |
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ccs_warn_log(r, "file mount %s %s %s 0x%lX", type, dev, dir, flags); |
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else if (!strcmp(type, CCS_MOUNT_MAKE_UNBINDABLE_KEYWORD) || |
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!strcmp(type, CCS_MOUNT_MAKE_PRIVATE_KEYWORD) || |
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!strcmp(type, CCS_MOUNT_MAKE_SLAVE_KEYWORD) || |
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!strcmp(type, CCS_MOUNT_MAKE_SHARED_KEYWORD)) |
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ccs_warn_log(r, "file mount %s %s 0x%lX", type, dir, flags); |
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else |
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ccs_warn_log(r, "file mount -t %s %s %s 0x%lX", type, dev, dir, |
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flags); |
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return ccs_supervisor(r, "file mount %s %s %s 0x%lX\n", |
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ccs_file_pattern(r->param.mount.dev), |
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ccs_file_pattern(r->param.mount.dir), type, |
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flags); |
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} |
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|
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static bool ccs_check_mount_acl(struct ccs_request_info *r, |
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const struct ccs_acl_info *ptr) |
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{ |
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const struct ccs_mount_acl *acl = |
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container_of(ptr, typeof(*acl), head); |
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return ccs_compare_number_union(r->param.mount.flags, &acl->flags) && |
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ccs_compare_name_union(r->param.mount.type, &acl->fs_type) && |
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ccs_compare_name_union(r->param.mount.dir, &acl->dir_name) && |
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(!r->param.mount.need_dev || |
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ccs_compare_name_union(r->param.mount.dev, &acl->dev_name)); |
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} |
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|
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/** |
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* ccs_mount_acl - Check permission for mount() operation. |
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* |
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* @r: Pointer to "struct ccs_request_info". |
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* @dev_name: Name of device file. |
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* @dir: Pointer to "struct path". |
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* @type: Name of filesystem type. |
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* @flags: Mount options. |
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* |
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* Returns 0 on success, negative value otherwise. |
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* |
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* Caller holds ccs_read_lock(). |
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*/ |
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static int ccs_mount_acl(struct ccs_request_info *r, char *dev_name, |
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struct path *dir, char *type, unsigned long flags) |
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{ |
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struct ccs_obj_info obj = { }; |
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struct path path; |
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struct file_system_type *fstype = NULL; |
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const char *requested_type = NULL; |
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const char *requested_dir_name = NULL; |
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const char *requested_dev_name = NULL; |
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struct ccs_path_info rtype; |
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struct ccs_path_info rdev; |
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struct ccs_path_info rdir; |
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int need_dev = 0; |
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int error = -ENOMEM; |
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r->obj = &obj; |
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|
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/* Get fstype. */ |
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requested_type = ccs_encode(type); |
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if (!requested_type) |
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goto out; |
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rtype.name = requested_type; |
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ccs_fill_path_info(&rtype); |
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|
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/* Get mount point. */ |
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obj.path2 = *dir; |
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requested_dir_name = ccs_realpath_from_path(dir); |
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if (!requested_dir_name) { |
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error = -ENOMEM; |
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goto out; |
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} |
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rdir.name = requested_dir_name; |
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ccs_fill_path_info(&rdir); |
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|
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/* Compare fs name. */ |
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if (!strcmp(type, CCS_MOUNT_REMOUNT_KEYWORD)) { |
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/* dev_name is ignored. */ |
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} else if (!strcmp(type, CCS_MOUNT_MAKE_UNBINDABLE_KEYWORD) || |
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!strcmp(type, CCS_MOUNT_MAKE_PRIVATE_KEYWORD) || |
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!strcmp(type, CCS_MOUNT_MAKE_SLAVE_KEYWORD) || |
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!strcmp(type, CCS_MOUNT_MAKE_SHARED_KEYWORD)) { |
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/* dev_name is ignored. */ |
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} else if (!strcmp(type, CCS_MOUNT_BIND_KEYWORD) || |
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!strcmp(type, CCS_MOUNT_MOVE_KEYWORD)) { |
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need_dev = -1; /* dev_name is a directory */ |
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} else { |
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fstype = get_fs_type(type); |
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if (!fstype) { |
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error = -ENODEV; |
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goto out; |
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} |
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if (fstype->fs_flags & FS_REQUIRES_DEV) |
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/* dev_name is a block device file. */ |
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need_dev = 1; |
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} |
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if (need_dev) { |
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/* Get mount point or device file. */ |
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if (ccs_get_path(dev_name, &path)) { |
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error = -ENOENT; |
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goto out; |
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} |
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obj.path1 = path; |
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requested_dev_name = ccs_realpath_from_path(&path); |
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if (!requested_dev_name) { |
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error = -ENOENT; |
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goto out; |
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} |
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} else { |
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/* Map dev_name to "<NULL>" if no dev_name given. */ |
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if (!dev_name) |
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dev_name = "<NULL>"; |
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requested_dev_name = ccs_encode(dev_name); |
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if (!requested_dev_name) { |
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error = -ENOMEM; |
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goto out; |
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} |
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} |
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rdev.name = requested_dev_name; |
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ccs_fill_path_info(&rdev); |
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r->param_type = CCS_TYPE_MOUNT_ACL; |
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r->param.mount.need_dev = need_dev; |
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r->param.mount.dev = &rdev; |
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r->param.mount.dir = &rdir; |
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r->param.mount.type = &rtype; |
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r->param.mount.flags = flags; |
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do { |
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ccs_check_acl(r, ccs_check_mount_acl); |
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error = ccs_audit_mount_log(r); |
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} while (error == CCS_RETRY_REQUEST); |
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out: |
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kfree(requested_dev_name); |
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kfree(requested_dir_name); |
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if (fstype) |
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ccsecurity_exports.put_filesystem(fstype); |
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kfree(requested_type); |
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/* Drop refcount obtained by ccs_get_path(). */ |
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if (obj.path1.dentry) |
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path_put(&obj.path1); |
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return error; |
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} |
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|
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/** |
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* ccs_mount_permission - Check permission for mount() operation. |
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* |
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* @dev_name: Name of device file. |
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* @path: Pointer to "struct path". |
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* @type: Name of filesystem type. Maybe NULL. |
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* @flags: Mount options. |
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* @data_page: Optional data. Maybe NULL. |
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* |
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* Returns 0 on success, negative value otherwise. |
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*/ |
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static int __ccs_mount_permission(char *dev_name, struct path *path, |
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char *type, unsigned long flags, |
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void *data_page) |
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{ |
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struct ccs_request_info r; |
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int error; |
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int idx; |
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if (ccs_init_request_info(&r, CCS_MAC_FILE_MOUNT) |
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== CCS_CONFIG_DISABLED) |
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return 0; |
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if ((flags & MS_MGC_MSK) == MS_MGC_VAL) |
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flags &= ~MS_MGC_MSK; |
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if (flags & MS_REMOUNT) { |
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type = CCS_MOUNT_REMOUNT_KEYWORD; |
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flags &= ~MS_REMOUNT; |
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} |
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if (flags & MS_MOVE) { |
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type = CCS_MOUNT_MOVE_KEYWORD; |
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flags &= ~MS_MOVE; |
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} |
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if (flags & MS_BIND) { |
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type = CCS_MOUNT_BIND_KEYWORD; |
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flags &= ~MS_BIND; |
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} |
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if (flags & MS_UNBINDABLE) { |
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type = CCS_MOUNT_MAKE_UNBINDABLE_KEYWORD; |
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flags &= ~MS_UNBINDABLE; |
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} |
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if (flags & MS_PRIVATE) { |
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type = CCS_MOUNT_MAKE_PRIVATE_KEYWORD; |
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flags &= ~MS_PRIVATE; |
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} |
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if (flags & MS_SLAVE) { |
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type = CCS_MOUNT_MAKE_SLAVE_KEYWORD; |
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flags &= ~MS_SLAVE; |
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} |
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if (flags & MS_SHARED) { |
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type = CCS_MOUNT_MAKE_SHARED_KEYWORD; |
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flags &= ~MS_SHARED; |
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} |
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if (!type) |
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type = "<NULL>"; |
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idx = ccs_read_lock(); |
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error = ccs_mount_acl(&r, dev_name, path, type, flags); |
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ccs_read_unlock(idx); |
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return error; |
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} |
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|
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#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 24) |
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static int ccs_old_mount_permission(char *dev_name, struct nameidata *nd, |
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char *type, unsigned long flags, |
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void *data_page) |
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{ |
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struct path path = { nd->mnt, nd->dentry }; |
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return __ccs_mount_permission(dev_name, &path, type, flags, data_page); |
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} |
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#endif |
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|
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void __init ccs_mount_init(void) |
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{ |
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 25) |
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ccsecurity_ops.mount_permission = __ccs_mount_permission; |
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#else |
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ccsecurity_ops.mount_permission = ccs_old_mount_permission; |
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#endif |
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} |
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