diff options
| -rw-r--r-- | security/selinux/include/security.h | 21 | ||||
| -rw-r--r-- | security/selinux/selinuxfs.c | 56 | ||||
| -rw-r--r-- | security/selinux/ss/Makefile | 2 | ||||
| -rw-r--r-- | security/selinux/ss/services.c | 3 | ||||
| -rw-r--r-- | security/selinux/ss/status.c | 129 |
5 files changed, 210 insertions, 1 deletions
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 1f7c2491d3dc..e390e31bb4bf 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -191,5 +191,26 @@ static inline int security_netlbl_sid_to_secattr(u32 sid, const char *security_get_initial_sid_context(u32 sid); +/* + * status notifier using mmap interface + */ +extern struct page *selinux_kernel_status_page(void); + +#define SELINUX_KERNEL_STATUS_VERSION 1 +struct selinux_kernel_status +{ + u32 version; /* version number of thie structure */ + u32 sequence; /* sequence number of seqlock logic */ + u32 enforcing; /* current setting of enforcing mode */ + u32 policyload; /* times of policy reloaded */ + u32 deny_unknown; /* current setting of deny_unknown */ + /* + * The version > 0 supports above members. + */ +} __attribute__((packed)); + +extern void selinux_status_update_setenforce(int enforcing); +extern void selinux_status_update_policyload(int seqno); + #endif /* _SELINUX_SECURITY_H_ */ diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 79a1bb635662..a2e7a8563b38 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -110,6 +110,7 @@ enum sel_inos { SEL_COMPAT_NET, /* whether to use old compat network packet controls */ SEL_REJECT_UNKNOWN, /* export unknown reject handling to userspace */ SEL_DENY_UNKNOWN, /* export unknown deny handling to userspace */ + SEL_STATUS, /* export current status using mmap() */ SEL_INO_NEXT, /* The next inode number to use */ }; @@ -171,6 +172,7 @@ static ssize_t sel_write_enforce(struct file *file, const char __user *buf, if (selinux_enforcing) avc_ss_reset(0); selnl_notify_setenforce(selinux_enforcing); + selinux_status_update_setenforce(selinux_enforcing); } length = count; out: @@ -205,6 +207,59 @@ static const struct file_operations sel_handle_unknown_ops = { .llseek = generic_file_llseek, }; +static int sel_open_handle_status(struct inode *inode, struct file *filp) +{ + struct page *status = selinux_kernel_status_page(); + + if (!status) + return -ENOMEM; + + filp->private_data = status; + + return 0; +} + +static ssize_t sel_read_handle_status(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + struct page *status = filp->private_data; + + BUG_ON(!status); + + return simple_read_from_buffer(buf, count, ppos, + page_address(status), + sizeof(struct selinux_kernel_status)); +} + +static int sel_mmap_handle_status(struct file *filp, + struct vm_area_struct *vma) +{ + struct page *status = filp->private_data; + unsigned long size = vma->vm_end - vma->vm_start; + + BUG_ON(!status); + + /* only allows one page from the head */ + if (vma->vm_pgoff > 0 || size != PAGE_SIZE) + return -EIO; + /* disallow writable mapping */ + if (vma->vm_flags & VM_WRITE) + return -EPERM; + /* disallow mprotect() turns it into writable */ + vma->vm_flags &= ~VM_MAYWRITE; + + return remap_pfn_range(vma, vma->vm_start, + page_to_pfn(status), + size, vma->vm_page_prot); +} + +static const struct file_operations sel_handle_status_ops = { + .open = sel_open_handle_status, + .read = sel_read_handle_status, + .mmap = sel_mmap_handle_status, + .llseek = generic_file_llseek, +}; + #ifdef CONFIG_SECURITY_SELINUX_DISABLE static ssize_t sel_write_disable(struct file *file, const char __user *buf, size_t count, loff_t *ppos) @@ -1612,6 +1667,7 @@ static int sel_fill_super(struct super_block *sb, void *data, int silent) [SEL_CHECKREQPROT] = {"checkreqprot", &sel_checkreqprot_ops, S_IRUGO|S_IWUSR}, [SEL_REJECT_UNKNOWN] = {"reject_unknown", &sel_handle_unknown_ops, S_IRUGO}, [SEL_DENY_UNKNOWN] = {"deny_unknown", &sel_handle_unknown_ops, S_IRUGO}, + [SEL_STATUS] = {"status", &sel_handle_status_ops, S_IRUGO}, /* last one */ {""} }; ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files); diff --git a/security/selinux/ss/Makefile b/security/selinux/ss/Makefile index 15d4e62917de..974e11c7cf54 100644 --- a/security/selinux/ss/Makefile +++ b/security/selinux/ss/Makefile @@ -5,5 +5,5 @@ EXTRA_CFLAGS += -Isecurity/selinux -Isecurity/selinux/include obj-y := ss.o -ss-y := ebitmap.o hashtab.o symtab.o sidtab.o avtab.o policydb.o services.o conditional.o mls.o +ss-y := ebitmap.o hashtab.o symtab.o sidtab.o avtab.o policydb.o services.o conditional.o mls.o status.o diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 9ea2feca3cd4..494ff527c174 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -1791,6 +1791,7 @@ int security_load_policy(void *data, size_t len) selinux_complete_init(); avc_ss_reset(seqno); selnl_notify_policyload(seqno); + selinux_status_update_policyload(seqno); selinux_netlbl_cache_invalidate(); selinux_xfrm_notify_policyload(); return 0; @@ -1870,6 +1871,7 @@ int security_load_policy(void *data, size_t len) avc_ss_reset(seqno); selnl_notify_policyload(seqno); + selinux_status_update_policyload(seqno); selinux_netlbl_cache_invalidate(); selinux_xfrm_notify_policyload(); @@ -2374,6 +2376,7 @@ out: if (!rc) { avc_ss_reset(seqno); selnl_notify_policyload(seqno); + selinux_status_update_policyload(seqno); selinux_xfrm_notify_policyload(); } return rc; diff --git a/security/selinux/ss/status.c b/security/selinux/ss/status.c new file mode 100644 index 000000000000..5d9b225f8568 --- /dev/null +++ b/security/selinux/ss/status.c @@ -0,0 +1,129 @@ +/* + * mmap based event notifications for SELinux + * + * Author: KaiGai Kohei <kaigai@ak.jp.nec.com> + * + * Copyright (C) 2010 NEC corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2, + * as published by the Free Software Foundation. + */ +#include <linux/kernel.h> +#include <linux/gfp.h> +#include <linux/mm.h> +#include <linux/mutex.h> +#include "avc.h" +#include "services.h" + +/* + * The selinux_status_page shall be exposed to userspace applications + * using mmap interface on /selinux/status. + * It enables to notify applications a few events that will cause reset + * of userspace access vector without context switching. + * + * The selinux_kernel_status structure on the head of status page is + * protected from concurrent accesses using seqlock logic, so userspace + * application should reference the status page according to the seqlock + * logic. + * + * Typically, application checks status->sequence at the head of access + * control routine. If it is odd-number, kernel is updating the status, + * so please wait for a moment. If it is changed from the last sequence + * number, it means something happen, so application will reset userspace + * avc, if needed. + * In most cases, application shall confirm the kernel status is not + * changed without any system call invocations. + */ +static struct page *selinux_status_page = NULL; +static DEFINE_MUTEX(selinux_status_lock); + +/* + * selinux_kernel_status_page + * + * It returns a reference to selinux_status_page. If the status page is + * not allocated yet, it also tries to allocate it at the first time. + */ +struct page *selinux_kernel_status_page(void) +{ + struct selinux_kernel_status *status; + struct page *result = NULL; + + mutex_lock(&selinux_status_lock); + if (!selinux_status_page) + { + selinux_status_page = alloc_page(GFP_KERNEL|__GFP_ZERO); + if (selinux_status_page) + { + status = page_address(selinux_status_page); + + status->version = SELINUX_KERNEL_STATUS_VERSION; + status->sequence = 0; + status->enforcing = selinux_enforcing; + /* + * NOTE: the next policyload event shall set + * a positive value on the status->policyload, + * although it may not be 1, but never zero. + * So, application can know it was updated. + */ + status->policyload = 0; + status->deny_unknown = !security_get_allow_unknown(); + } + } + result = selinux_status_page; + mutex_unlock(&selinux_status_lock); + + return result; +} + +/* + * selinux_status_update_setenforce + * + * It updates status of the current enforcing/permissive mode. + */ +void selinux_status_update_setenforce(int enforcing) +{ + struct selinux_kernel_status *status; + + mutex_lock(&selinux_status_lock); + if (selinux_status_page) + { + status = page_address(selinux_status_page); + + status->sequence++; + smp_wmb(); + + status->enforcing = enforcing; + + smp_wmb(); + status->sequence++; + } + mutex_unlock(&selinux_status_lock); +} + +/* + * selinux_status_update_policyload + * + * It updates status of the times of policy reloaded, and current + * setting of deny_unknown. + */ +void selinux_status_update_policyload(int seqno) +{ + struct selinux_kernel_status *status; + + mutex_lock(&selinux_status_lock); + if (selinux_status_page) + { + status = page_address(selinux_status_page); + + status->sequence++; + smp_wmb(); + + status->policyload = seqno; + status->deny_unknown = !security_get_allow_unknown(); + + smp_wmb(); + status->sequence++; + } + mutex_unlock(&selinux_status_lock); +} |