1 files changed, 49 insertions, 239 deletions

diff --git a/kernel/capability.c b/kernel/capability.c
index 33e51e78c2d8..36b4b4daebec 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -7,6 +7,7 @@
  * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
  */
 
+#include <linux/audit.h>
 #include <linux/capability.h>
 #include <linux/mm.h>
 #include <linux/module.h>
@@ -14,12 +15,7 @@
 #include <linux/syscalls.h>
 #include <linux/pid_namespace.h>
 #include <asm/uaccess.h>
-
-/*
- * This lock protects task->cap_* for all tasks including current.
- * Locking rule: acquire this prior to tasklist_lock.
- */
-static DEFINE_SPINLOCK(task_capability_lock);
+#include "cred-internals.h"
 
 /*
  * Leveraged for setting/resetting capabilities
@@ -33,6 +29,17 @@ EXPORT_SYMBOL(__cap_empty_set);
 EXPORT_SYMBOL(__cap_full_set);
 EXPORT_SYMBOL(__cap_init_eff_set);
 
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
+int file_caps_enabled = 1;
+
+static int __init file_caps_disable(char *str)
+{
+        file_caps_enabled = 0;
+        return 1;
+}
+__setup("no_file_caps", file_caps_disable);
+#endif
+
 /*
  * More recent versions of libcap are available from:
  *
@@ -115,167 +122,12 @@ static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
         return 0;
 }
 
-#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
-
-/*
- * Without filesystem capability support, we nominally support one process
- * setting the capabilities of another
- */
-static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
-                                     kernel_cap_t *pIp, kernel_cap_t *pPp)
-{
-        struct task_struct *target;
-        int ret;
-
-        spin_lock(&task_capability_lock);
-        read_lock(&tasklist_lock);
-
-        if (pid && pid != task_pid_vnr(current)) {
-                target = find_task_by_vpid(pid);
-                if (!target) {
-                        ret = -ESRCH;
-                        goto out;
-                }
-        } else
-                target = current;
-
-        ret = security_capget(target, pEp, pIp, pPp);
-
-out:
-        read_unlock(&tasklist_lock);
-        spin_unlock(&task_capability_lock);
-
-        return ret;
-}
-
-/*
- * cap_set_pg - set capabilities for all processes in a given process
- * group.  We call this holding task_capability_lock and tasklist_lock.
- */
-static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
-                             kernel_cap_t *inheritable,
-                             kernel_cap_t *permitted)
-{
-        struct task_struct *g, *target;
-        int ret = -EPERM;
-        int found = 0;
-        struct pid *pgrp;
-
-        spin_lock(&task_capability_lock);
-        read_lock(&tasklist_lock);
-
-        pgrp = find_vpid(pgrp_nr);
-        do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
-                target = g;
-                while_each_thread(g, target) {
-                        if (!security_capset_check(target, effective,
-                                                   inheritable, permitted)) {
-                                security_capset_set(target, effective,
-                                                    inheritable, permitted);
-                                ret = 0;
-                        }
-                        found = 1;
-                }
-        } while_each_pid_task(pgrp, PIDTYPE_PGID, g);
-
-        read_unlock(&tasklist_lock);
-        spin_unlock(&task_capability_lock);
-
-        if (!found)
-                ret = 0;
-        return ret;
-}
-
-/*
- * cap_set_all - set capabilities for all processes other than init
- * and self.  We call this holding task_capability_lock and tasklist_lock.
- */
-static inline int cap_set_all(kernel_cap_t *effective,
-                              kernel_cap_t *inheritable,
-                              kernel_cap_t *permitted)
-{
-        struct task_struct *g, *target;
-        int ret = -EPERM;
-        int found = 0;
-
-        spin_lock(&task_capability_lock);
-        read_lock(&tasklist_lock);
-
-        do_each_thread(g, target) {
-                if (target == current
-                    || is_container_init(target->group_leader))
-                        continue;
-                found = 1;
-                if (security_capset_check(target, effective, inheritable,
-                                          permitted))
-                        continue;
-                ret = 0;
-                security_capset_set(target, effective, inheritable, permitted);
-        } while_each_thread(g, target);
-
-        read_unlock(&tasklist_lock);
-        spin_unlock(&task_capability_lock);
-
-        if (!found)
-                ret = 0;
-
-        return ret;
-}
-
-/*
- * Given the target pid does not refer to the current process we
- * need more elaborate support... (This support is not present when
- * filesystem capabilities are configured.)
- */
-static inline int do_sys_capset_other_tasks(pid_t pid, kernel_cap_t *effective,
-                                            kernel_cap_t *inheritable,
-                                            kernel_cap_t *permitted)
-{
-        struct task_struct *target;
-        int ret;
-
-        if (!capable(CAP_SETPCAP))
-                return -EPERM;
-
-        if (pid == -1)            /* all procs other than current and init */
-                return cap_set_all(effective, inheritable, permitted);
-
-        else if (pid < 0)                    /* all procs in process group */
-                return cap_set_pg(-pid, effective, inheritable, permitted);
-
-        /* target != current */
-        spin_lock(&task_capability_lock);
-        read_lock(&tasklist_lock);
-
-        target = find_task_by_vpid(pid);
-        if (!target)
-                ret = -ESRCH;
-        else {
-                ret = security_capset_check(target, effective, inheritable,
-                                            permitted);
-
-                /* having verified that the proposed changes are legal,
-                   we now put them into effect. */
-                if (!ret)
-                        security_capset_set(target, effective, inheritable,
-                                            permitted);
-        }
-
-        read_unlock(&tasklist_lock);
-        spin_unlock(&task_capability_lock);
-
-        return ret;
-}
-
-#else /* ie., def CONFIG_SECURITY_FILE_CAPABILITIES */
-
 /*
- * If we have configured with filesystem capability support, then the
- * only thing that can change the capabilities of the current process
- * is the current process. As such, we can't be in this code at the
- * same time as we are in the process of setting capabilities in this
- * process. The net result is that we can limit our use of locks to
- * when we are reading the caps of another process.
+ * The only thing that can change the capabilities of the current
+ * process is the current process. As such, we can't be in this code
+ * at the same time as we are in the process of setting capabilities
+ * in this process. The net result is that we can limit our use of
+ * locks to when we are reading the caps of another process.
  */
 static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
                                      kernel_cap_t *pIp, kernel_cap_t *pPp)
@@ -285,7 +137,6 @@ static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
         if (pid && (pid != task_pid_vnr(current))) {
                 struct task_struct *target;
 
-                spin_lock(&task_capability_lock);
                 read_lock(&tasklist_lock);
 
                 target = find_task_by_vpid(pid);
@@ -295,50 +146,12 @@ static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
                         ret = security_capget(target, pEp, pIp, pPp);
 
                 read_unlock(&tasklist_lock);
-                spin_unlock(&task_capability_lock);
         } else
                 ret = security_capget(current, pEp, pIp, pPp);
 
         return ret;
 }
 
-/*
- * With filesystem capability support configured, the kernel does not
- * permit the changing of capabilities in one process by another
- * process. (CAP_SETPCAP has much less broad semantics when configured
- * this way.)
- */
-static inline int do_sys_capset_other_tasks(pid_t pid,
-                                            kernel_cap_t *effective,
-                                            kernel_cap_t *inheritable,
-                                            kernel_cap_t *permitted)
-{
-        return -EPERM;
-}
-
-#endif /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
-
-/*
- * Atomically modify the effective capabilities returning the original
- * value. No permission check is performed here - it is assumed that the
- * caller is permitted to set the desired effective capabilities.
- */
-kernel_cap_t cap_set_effective(const kernel_cap_t pE_new)
-{
-        kernel_cap_t pE_old;
-
-        spin_lock(&task_capability_lock);
-
-        pE_old = current->cap_effective;
-        current->cap_effective = pE_new;
-
-        spin_unlock(&task_capability_lock);
-
-        return pE_old;
-}
-
-EXPORT_SYMBOL(cap_set_effective);
-
 /**
  * sys_capget - get the capabilities of a given process.
  * @header: pointer to struct that contains capability version and
@@ -366,7 +179,6 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
                 return -EINVAL;
 
         ret = cap_get_target_pid(pid, &pE, &pI, &pP);
-
         if (!ret) {
                 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
                 unsigned i;
@@ -412,16 +224,14 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
  * @data: pointer to struct that contains the effective, permitted,
  *      and inheritable capabilities
  *
- * Set capabilities for a given process, all processes, or all
- * processes in a given process group.
+ * Set capabilities for the current process only.  The ability to any other
+ * process(es) has been deprecated and removed.
  *
  * The restrictions on setting capabilities are specified as:
  *
- * [pid is for the 'target' task.  'current' is the calling task.]
- *
- * I: any raised capabilities must be a subset of the (old current) permitted
- * P: any raised capabilities must be a subset of the (old current) permitted
- * E: must be set to a subset of (new target) permitted
+ * I: any raised capabilities must be a subset of the old permitted
+ * P: any raised capabilities must be a subset of the old permitted
+ * E: must be set to a subset of new permitted
  *
  * Returns 0 on success and < 0 on error.
  */
@@ -430,6 +240,7 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
         struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
         unsigned i, tocopy;
         kernel_cap_t inheritable, permitted, effective;
+        struct cred *new;
         int ret;
         pid_t pid;
 
@@ -440,10 +251,13 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
         if (get_user(pid, &header->pid))
                 return -EFAULT;
 
-        if (copy_from_user(&kdata, data, tocopy
-                           * sizeof(struct __user_cap_data_struct))) {
+        /* may only affect current now */
+        if (pid != 0 && pid != task_pid_vnr(current))
+                return -EPERM;
+
+        if (copy_from_user(&kdata, data,
+                           tocopy * sizeof(struct __user_cap_data_struct)))
                 return -EFAULT;
-        }
 
         for (i = 0; i < tocopy; i++) {
                 effective.cap[i] = kdata[i].effective;
@@ -457,32 +271,23 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
                 i++;
         }
 
-        if (pid && (pid != task_pid_vnr(current)))
-                ret = do_sys_capset_other_tasks(pid, &effective, &inheritable,
-                                                &permitted);
-        else {
-                /*
-                 * This lock is required even when filesystem
-                 * capability support is configured - it protects the
-                 * sys_capget() call from returning incorrect data in
-                 * the case that the targeted process is not the
-                 * current one.
-                 */
-                spin_lock(&task_capability_lock);
+        new = prepare_creds();
+        if (!new)
+                return -ENOMEM;
 
-                ret = security_capset_check(current, &effective, &inheritable,
-                                            &permitted);
-                /*
-                 * Having verified that the proposed changes are
-                 * legal, we now put them into effect.
-                 */
-                if (!ret)
-                        security_capset_set(current, &effective, &inheritable,
-                                            &permitted);
-                spin_unlock(&task_capability_lock);
-        }
+        ret = security_capset(new, current_cred(),
+                              &effective, &inheritable, &permitted);
+        if (ret < 0)
+                goto error;
+
+        ret = audit_log_capset(pid, new, current_cred());
+        if (ret < 0)
+                return ret;
 
+        return commit_creds(new);
 
+error:
+        abort_creds(new);
         return ret;
 }
 
@@ -498,6 +303,11 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
  */
 int capable(int cap)
 {
+        if (unlikely(!cap_valid(cap))) {
+                printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
+                BUG();
+        }
+
         if (has_capability(current, cap)) {
                 current->flags |= PF_SUPERPRIV;
                 return 1;