Merge branch 'next' into for-linus

1 files changed, 537 insertions, 293 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index 3976613db82..79713545cd6 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/capability.h>
+#include <linux/audit.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -29,7 +30,7 @@
 
 int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
 {
-	NETLINK_CB(skb).eff_cap = current->cap_effective;
+	NETLINK_CB(skb).eff_cap = current_cap();
 	return 0;
 }
 
@@ -39,23 +40,41 @@ int cap_netlink_recv(struct sk_buff *skb, int cap)
 		return -EPERM;
 	return 0;
 }
-
 EXPORT_SYMBOL(cap_netlink_recv);
 
-/*
+/**
+ * cap_capable - Determine whether a task has a particular effective capability
+ * @tsk: The task to query
+ * @cap: The capability to check for
+ * @audit: Whether to write an audit message or not
+ *
+ * Determine whether the nominated task has the specified capability amongst
+ * its effective set, returning 0 if it does, -ve if it does not.
+ *
  * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
- * function.  That is, it has the reverse semantics: cap_capable()
- * returns 0 when a task has a capability, but the kernel's capable()
- * returns 1 for this case.
+ * function.  That is, it has the reverse semantics: cap_capable() returns 0
+ * when a task has a capability, but the kernel's capable() returns 1 for this
+ * case.
  */
-int cap_capable (struct task_struct *tsk, int cap)
+int cap_capable(struct task_struct *tsk, int cap, int audit)
 {
+	__u32 cap_raised;
+
 	/* Derived from include/linux/sched.h:capable. */
-	if (cap_raised(tsk->cap_effective, cap))
-		return 0;
-	return -EPERM;
+	rcu_read_lock();
+	cap_raised = cap_raised(__task_cred(tsk)->cap_effective, cap);
+	rcu_read_unlock();
+	return cap_raised ? 0 : -EPERM;
 }
 
+/**
+ * cap_settime - Determine whether the current process may set the system clock
+ * @ts: The time to set
+ * @tz: The timezone to set
+ *
+ * Determine whether the current process may set the system clock and timezone
+ * information, returning 0 if permission granted, -ve if denied.
+ */
 int cap_settime(struct timespec *ts, struct timezone *tz)
 {
 	if (!capable(CAP_SYS_TIME))
@@ -63,121 +82,157 @@ int cap_settime(struct timespec *ts, struct timezone *tz)
 	return 0;
 }
 
+/**
+ * cap_ptrace_may_access - Determine whether the current process may access
+ *			   another
+ * @child: The process to be accessed
+ * @mode: The mode of attachment.
+ *
+ * Determine whether a process may access another, returning 0 if permission
+ * granted, -ve if denied.
+ */
 int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
 {
-	/* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
-	if (cap_issubset(child->cap_permitted, current->cap_permitted))
-		return 0;
-	if (capable(CAP_SYS_PTRACE))
-		return 0;
-	return -EPERM;
+	int ret = 0;
+
+	rcu_read_lock();
+	if (!cap_issubset(__task_cred(child)->cap_permitted,
+			  current_cred()->cap_permitted) &&
+	    !capable(CAP_SYS_PTRACE))
+		ret = -EPERM;
+	rcu_read_unlock();
+	return ret;
 }
 
+/**
+ * cap_ptrace_traceme - Determine whether another process may trace the current
+ * @parent: The task proposed to be the tracer
+ *
+ * Determine whether the nominated task is permitted to trace the current
+ * process, returning 0 if permission is granted, -ve if denied.
+ */
 int cap_ptrace_traceme(struct task_struct *parent)
 {
-	/* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
-	if (cap_issubset(current->cap_permitted, parent->cap_permitted))
-		return 0;
-	if (has_capability(parent, CAP_SYS_PTRACE))
-		return 0;
-	return -EPERM;
+	int ret = 0;
+
+	rcu_read_lock();
+	if (!cap_issubset(current_cred()->cap_permitted,
+			  __task_cred(parent)->cap_permitted) &&
+	    !has_capability(parent, CAP_SYS_PTRACE))
+		ret = -EPERM;
+	rcu_read_unlock();
+	return ret;
 }
 
-int cap_capget (struct task_struct *target, kernel_cap_t *effective,
-		kernel_cap_t *inheritable, kernel_cap_t *permitted)
+/**
+ * cap_capget - Retrieve a task's capability sets
+ * @target: The task from which to retrieve the capability sets
+ * @effective: The place to record the effective set
+ * @inheritable: The place to record the inheritable set
+ * @permitted: The place to record the permitted set
+ *
+ * This function retrieves the capabilities of the nominated task and returns
+ * them to the caller.
+ */
+int cap_capget(struct task_struct *target, kernel_cap_t *effective,
+	       kernel_cap_t *inheritable, kernel_cap_t *permitted)
 {
+	const struct cred *cred;
+
 	/* Derived from kernel/capability.c:sys_capget. */
-	*effective = target->cap_effective;
-	*inheritable = target->cap_inheritable;
-	*permitted = target->cap_permitted;
+	rcu_read_lock();
+	cred = __task_cred(target);
+	*effective   = cred->cap_effective;
+	*inheritable = cred->cap_inheritable;
+	*permitted   = cred->cap_permitted;
+	rcu_read_unlock();
 	return 0;
 }
 
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
-
-static inline int cap_block_setpcap(struct task_struct *target)
-{
-	/*
-	 * No support for remote process capability manipulation with
-	 * filesystem capability support.
-	 */
-	return (target != current);
-}
-
+/*
+ * Determine whether the inheritable capabilities are limited to the old
+ * permitted set.  Returns 1 if they are limited, 0 if they are not.
+ */
 static inline int cap_inh_is_capped(void)
 {
-	/*
-	 * Return 1 if changes to the inheritable set are limited
-	 * to the old permitted set. That is, if the current task
-	 * does *not* possess the CAP_SETPCAP capability.
-	 */
-	return (cap_capable(current, CAP_SETPCAP) != 0);
-}
-
-static inline int cap_limit_ptraced_target(void) { return 1; }
-
-#else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 
-static inline int cap_block_setpcap(struct task_struct *t) { return 0; }
-static inline int cap_inh_is_capped(void) { return 1; }
-static inline int cap_limit_ptraced_target(void)
-{
-	return !capable(CAP_SETPCAP);
+	/* they are so limited unless the current task has the CAP_SETPCAP
+	 * capability
+	 */
+	if (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
+		return 0;
+#endif
+	return 1;
 }
 
-#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
-
-int cap_capset_check (struct task_struct *target, kernel_cap_t *effective,
-		      kernel_cap_t *inheritable, kernel_cap_t *permitted)
-{
-	if (cap_block_setpcap(target)) {
-		return -EPERM;
-	}
-	if (cap_inh_is_capped()
-	    && !cap_issubset(*inheritable,
-			     cap_combine(target->cap_inheritable,
-					 current->cap_permitted))) {
+/**
+ * cap_capset - Validate and apply proposed changes to current's capabilities
+ * @new: The proposed new credentials; alterations should be made here
+ * @old: The current task's current credentials
+ * @effective: A pointer to the proposed new effective capabilities set
+ * @inheritable: A pointer to the proposed new inheritable capabilities set
+ * @permitted: A pointer to the proposed new permitted capabilities set
+ *
+ * This function validates and applies a proposed mass change to the current
+ * process's capability sets.  The changes are made to the proposed new
+ * credentials, and assuming no error, will be committed by the caller of LSM.
+ */
+int cap_capset(struct cred *new,
+	       const struct cred *old,
+	       const kernel_cap_t *effective,
+	       const kernel_cap_t *inheritable,
+	       const kernel_cap_t *permitted)
+{
+	if (cap_inh_is_capped() &&
+	    !cap_issubset(*inheritable,
+			  cap_combine(old->cap_inheritable,
+				      old->cap_permitted)))
 		/* incapable of using this inheritable set */
 		return -EPERM;
-	}
+
 	if (!cap_issubset(*inheritable,
-			   cap_combine(target->cap_inheritable,
-				       current->cap_bset))) {
+			  cap_combine(old->cap_inheritable,
+				      old->cap_bset)))
 		/* no new pI capabilities outside bounding set */
 		return -EPERM;
-	}
 
 	/* verify restrictions on target's new Permitted set */
-	if (!cap_issubset (*permitted,
-			   cap_combine (target->cap_permitted,
-					current->cap_permitted))) {
+	if (!cap_issubset(*permitted, old->cap_permitted))
 		return -EPERM;
-	}
 
 	/* verify the _new_Effective_ is a subset of the _new_Permitted_ */
-	if (!cap_issubset (*effective, *permitted)) {
+	if (!cap_issubset(*effective, *permitted))
 		return -EPERM;
-	}
 
+	new->cap_effective   = *effective;
+	new->cap_inheritable = *inheritable;
+	new->cap_permitted   = *permitted;
 	return 0;
 }
 
-void cap_capset_set (struct task_struct *target, kernel_cap_t *effective,
-		     kernel_cap_t *inheritable, kernel_cap_t *permitted)
-{
-	target->cap_effective = *effective;
-	target->cap_inheritable = *inheritable;
-	target->cap_permitted = *permitted;
-}
-
+/*
+ * Clear proposed capability sets for execve().
+ */
 static inline void bprm_clear_caps(struct linux_binprm *bprm)
 {
-	cap_clear(bprm->cap_post_exec_permitted);
+	cap_clear(bprm->cred->cap_permitted);
 	bprm->cap_effective = false;
 }
 
 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 
+/**
+ * cap_inode_need_killpriv - Determine if inode change affects privileges
+ * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
+ *
+ * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
+ * affects the security markings on that inode, and if it is, should
+ * inode_killpriv() be invoked or the change rejected?
+ *
+ * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
+ * -ve to deny the change.
+ */
 int cap_inode_need_killpriv(struct dentry *dentry)
 {
 	struct inode *inode = dentry->d_inode;
@@ -192,6 +247,14 @@ int cap_inode_need_killpriv(struct dentry *dentry)
 	return 1;
 }
 
+/**
+ * cap_inode_killpriv - Erase the security markings on an inode
+ * @dentry: The inode/dentry to alter
+ *
+ * Erase the privilege-enhancing security markings on an inode.
+ *
+ * Returns 0 if successful, -ve on error.
+ */
 int cap_inode_killpriv(struct dentry *dentry)
 {
 	struct inode *inode = dentry->d_inode;
@@ -202,19 +265,75 @@ int cap_inode_killpriv(struct dentry *dentry)
 	return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
 }
 
-static inline int cap_from_disk(struct vfs_cap_data *caps,
-				struct linux_binprm *bprm, unsigned size)
+/*
+ * Calculate the new process capability sets from the capability sets attached
+ * to a file.
+ */
+static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
+					  struct linux_binprm *bprm,
+					  bool *effective)
+{
+	struct cred *new = bprm->cred;
+	unsigned i;
+	int ret = 0;
+
+	if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
+		*effective = true;
+
+	CAP_FOR_EACH_U32(i) {
+		__u32 permitted = caps->permitted.cap[i];
+		__u32 inheritable = caps->inheritable.cap[i];
+
+		/*
+		 * pP' = (X & fP) | (pI & fI)
+		 */
+		new->cap_permitted.cap[i] =
+			(new->cap_bset.cap[i] & permitted) |
+			(new->cap_inheritable.cap[i] & inheritable);
+
+		if (permitted & ~new->cap_permitted.cap[i])
+			/* insufficient to execute correctly */
+			ret = -EPERM;
+	}
+
+	/*
+	 * For legacy apps, with no internal support for recognizing they
+	 * do not have enough capabilities, we return an error if they are
+	 * missing some "forced" (aka file-permitted) capabilities.
+	 */
+	return *effective ? ret : 0;
+}
+
+/*
+ * Extract the on-exec-apply capability sets for an executable file.
+ */
+int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
 {
+	struct inode *inode = dentry->d_inode;
 	__u32 magic_etc;
 	unsigned tocopy, i;
-	int ret;
+	int size;
+	struct vfs_cap_data caps;
+
+	memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
+
+	if (!inode || !inode->i_op || !inode->i_op->getxattr)
+		return -ENODATA;
+
+	size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
+				   XATTR_CAPS_SZ);
+	if (size == -ENODATA || size == -EOPNOTSUPP)
+		/* no data, that's ok */
+		return -ENODATA;
+	if (size < 0)
+		return size;
 
 	if (size < sizeof(magic_etc))
 		return -EINVAL;
 
-	magic_etc = le32_to_cpu(caps->magic_etc);
+	cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc);
 
-	switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
+	switch (magic_etc & VFS_CAP_REVISION_MASK) {
 	case VFS_CAP_REVISION_1:
 		if (size != XATTR_CAPS_SZ_1)
 			return -EINVAL;
@@ -229,77 +348,48 @@ static inline int cap_from_disk(struct vfs_cap_data *caps,
 		return -EINVAL;
 	}
 
-	if (magic_etc & VFS_CAP_FLAGS_EFFECTIVE) {
-		bprm->cap_effective = true;
-	} else {
-		bprm->cap_effective = false;
-	}
-
-	ret = 0;
-
 	CAP_FOR_EACH_U32(i) {
-		__u32 value_cpu;
-
-		if (i >= tocopy) {
-			/*
-			 * Legacy capability sets have no upper bits
-			 */
-			bprm->cap_post_exec_permitted.cap[i] = 0;
-			continue;
-		}
-		/*
-		 * pP' = (X & fP) | (pI & fI)
-		 */
-		value_cpu = le32_to_cpu(caps->data[i].permitted);
-		bprm->cap_post_exec_permitted.cap[i] =
-			(current->cap_bset.cap[i] & value_cpu) |
-			(current->cap_inheritable.cap[i] &
-				le32_to_cpu(caps->data[i].inheritable));
-		if (value_cpu & ~bprm->cap_post_exec_permitted.cap[i]) {
-			/*
-			 * insufficient to execute correctly
-			 */
-			ret = -EPERM;
-		}
+		if (i >= tocopy)
+			break;
+		cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted);
+		cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable);
 	}
 
-	/*
-	 * For legacy apps, with no internal support for recognizing they
-	 * do not have enough capabilities, we return an error if they are
-	 * missing some "forced" (aka file-permitted) capabilities.
-	 */
-	return bprm->cap_effective ? ret : 0;
+	return 0;
 }
 
-/* Locate any VFS capabilities: */
-static int get_file_caps(struct linux_binprm *bprm)
+/*
+ * Attempt to get the on-exec apply capability sets for an executable file from
+ * its xattrs and, if present, apply them to the proposed credentials being
+ * constructed by execve().
+ */
+static int get_file_caps(struct linux_binprm *bprm, bool *effective)
 {
 	struct dentry *dentry;
 	int rc = 0;
-	struct vfs_cap_data vcaps;
-	struct inode *inode;
+	struct cpu_vfs_cap_data vcaps;
 
 	bprm_clear_caps(bprm);
 
+	if (!file_caps_enabled)
+		return 0;
+
 	if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
 		return 0;
 
 	dentry = dget(bprm->file->f_dentry);
-	inode = dentry->d_inode;
-	if (!inode->i_op || !inode->i_op->getxattr)
-		goto out;
 
-	rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, &vcaps,
-				   XATTR_CAPS_SZ);
-	if (rc == -ENODATA || rc == -EOPNOTSUPP) {
-		/* no data, that's ok */
-		rc = 0;
+	rc = get_vfs_caps_from_disk(dentry, &vcaps);
+	if (rc < 0) {
+		if (rc == -EINVAL)
+			printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n",
+				__func__, rc, bprm->filename);
+		else if (rc == -ENODATA)
+			rc = 0;
 		goto out;
 	}
-	if (rc < 0)
-		goto out;
 
-	rc = cap_from_disk(&vcaps, bprm, rc);
+	rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective);
 	if (rc == -EINVAL)
 		printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
 		       __func__, rc, bprm->filename);
@@ -323,18 +413,57 @@ int cap_inode_killpriv(struct dentry *dentry)
 	return 0;
 }
 
-static inline int get_file_caps(struct linux_binprm *bprm)
+int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
+{
+	memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
+ 	return -ENODATA;
+}
+
+static inline int get_file_caps(struct linux_binprm *bprm, bool *effective)
 {
 	bprm_clear_caps(bprm);
 	return 0;
 }
 #endif
 
-int cap_bprm_set_security (struct linux_binprm *bprm)
+/*
+ * Determine whether a exec'ing process's new permitted capabilities should be
+ * limited to just what it already has.
+ *
+ * This prevents processes that are being ptraced from gaining access to
+ * CAP_SETPCAP, unless the process they're tracing already has it, and the
+ * binary they're executing has filecaps that elevate it.
+ *
+ *  Returns 1 if they should be limited, 0 if they are not.
+ */
+static inline int cap_limit_ptraced_target(void)
+{
+#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
+	if (capable(CAP_SETPCAP))
+		return 0;
+#endif
+	return 1;
+}
+
+/**
+ * cap_bprm_set_creds - Set up the proposed credentials for execve().
+ * @bprm: The execution parameters, including the proposed creds
+ *
+ * Set up the proposed credentials for a new execution context being
+ * constructed by execve().  The proposed creds in @bprm->cred is altered,
+ * which won't take effect immediately.  Returns 0 if successful, -ve on error.
+ */
+int cap_bprm_set_creds(struct linux_binprm *bprm)
 {
+	const struct cred *old = current_cred();
+	struct cred *new = bprm->cred;
+	bool effective;
 	int ret;
 
-	ret = get_file_caps(bprm);
+	effective = false;
+	ret = get_file_caps(bprm, &effective);
+	if (ret < 0)
+		return ret;
 
 	if (!issecure(SECURE_NOROOT)) {
 		/*
@@ -342,75 +471,113 @@ int cap_bprm_set_security (struct linux_binprm *bprm)
 		 * executables under compatibility mode, we override the
 		 * capability sets for the file.
 		 *
-		 * If only the real uid is 0, we do not set the effective
-		 * bit.
+		 * If only the real uid is 0, we do not set the effective bit.
 		 */
-		if (bprm->e_uid == 0 || current->uid == 0) {
+		if (new->euid == 0 || new->uid == 0) {
 			/* pP' = (cap_bset & ~0) | (pI & ~0) */
-			bprm->cap_post_exec_permitted = cap_combine(
-				current->cap_bset, current->cap_inheritable
-				);
-			bprm->cap_effective = (bprm->e_uid == 0);
-			ret = 0;
+			new->cap_permitted = cap_combine(old->cap_bset,
+							 old->cap_inheritable);
 		}
+		if (new->euid == 0)
+			effective = true;
 	}
 
-	return ret;
-}
-
-void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
-{
-	if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
-	    !cap_issubset(bprm->cap_post_exec_permitted,
-			  current->cap_permitted)) {
-		set_dumpable(current->mm, suid_dumpable);
-		current->pdeath_signal = 0;
-
-		if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
-			if (!capable(CAP_SETUID)) {
-				bprm->e_uid = current->uid;
-				bprm->e_gid = current->gid;
-			}
-			if (cap_limit_ptraced_target()) {
-				bprm->cap_post_exec_permitted = cap_intersect(
-					bprm->cap_post_exec_permitted,
-					current->cap_permitted);
-			}
+	/* Don't let someone trace a set[ug]id/setpcap binary with the revised
+	 * credentials unless they have the appropriate permit
+	 */
+	if ((new->euid != old->uid ||
+	     new->egid != old->gid ||
+	     !cap_issubset(new->cap_permitted, old->cap_permitted)) &&
+	    bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
+		/* downgrade; they get no more than they had, and maybe less */
+		if (!capable(CAP_SETUID)) {
+			new->euid = new->uid;
+			new->egid = new->gid;
 		}
+		if (cap_limit_ptraced_target())
+			new->cap_permitted = cap_intersect(new->cap_permitted,
+							   old->cap_permitted);
 	}
 
-	current->suid = current->euid = current->fsuid = bprm->e_uid;
-	current->sgid = current->egid = current->fsgid = bprm->e_gid;
+	new->suid = new->fsuid = new->euid;
+	new->sgid = new->fsgid = new->egid;
 
-	/* For init, we want to retain the capabilities set
-	 * in the init_task struct. Thus we skip the usual
-	 * capability rules */
+	/* For init, we want to retain the capabilities set in the initial
+	 * task.  Thus we skip the usual capability rules
+	 */
 	if (!is_global_init(current)) {
-		current->cap_permitted = bprm->cap_post_exec_permitted;
-		if (bprm->cap_effective)
-			current->cap_effective = bprm->cap_post_exec_permitted;
+		if (effective)
+			new->cap_effective = new->cap_permitted;
 		else
-			cap_clear(current->cap_effective);
+			cap_clear(new->cap_effective);
 	}
+	bprm->cap_effective = effective;
 
-	/* AUD: Audit candidate if current->cap_effective is set */
+	/*
+	 * Audit candidate if current->cap_effective is set
+	 *
+	 * We do not bother to audit if 3 things are true:
+	 *   1) cap_effective has all caps
+	 *   2) we are root
+	 *   3) root is supposed to have all caps (SECURE_NOROOT)
+	 * Since this is just a normal root execing a process.
+	 *
+	 * Number 1 above might fail if you don't have a full bset, but I think
+	 * that is interesting information to audit.
+	 */
+	if (!cap_isclear(new->cap_effective)) {
+		if (!cap_issubset(CAP_FULL_SET, new->cap_effective) ||
+		    new->euid != 0 || new->uid != 0 ||
+		    issecure(SECURE_NOROOT)) {
+			ret = audit_log_bprm_fcaps(bprm, new, old);
+			if (ret < 0)
+				return ret;
+		}
+	}
 
-	current->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+	new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+	return 0;
 }
 
-int cap_bprm_secureexec (struct linux_binprm *bprm)
+/**
+ * cap_bprm_secureexec - Determine whether a secure execution is required
+ * @bprm: The execution parameters
+ *
+ * Determine whether a secure execution is required, return 1 if it is, and 0
+ * if it is not.
+ *
+ * The credentials have been committed by this point, and so are no longer
+ * available through @bprm->cred.
+ */
+int cap_bprm_secureexec(struct linux_binprm *bprm)
 {
-	if (current->uid != 0) {
+	const struct cred *cred = current_cred();
+
+	if (cred->uid != 0) {
 		if (bprm->cap_effective)
 			return 1;
-		if (!cap_isclear(bprm->cap_post_exec_permitted))
+		if (!cap_isclear(cred->cap_permitted))
 			return 1;
 	}
 
-	return (current->euid != current->uid ||
-		current->egid != current->gid);
+	return (cred->euid != cred->uid ||
+		cred->egid != cred->gid);
 }
 
+/**
+ * cap_inode_setxattr - Determine whether an xattr may be altered
+ * @dentry: The inode/dentry being altered
+ * @name: The name of the xattr to be changed
+ * @value: The value that the xattr will be changed to
+ * @size: The size of value
+ * @flags: The replacement flag
+ *
+ * Determine whether an xattr may be altered or set on an inode, returning 0 if
+ * permission is granted, -ve if denied.
+ *
+ * This is used to make sure security xattrs don't get updated or set by those
+ * who aren't privileged to do so.
+ */
 int cap_inode_setxattr(struct dentry *dentry, const char *name,
 		       const void *value, size_t size, int flags)
 {
@@ -418,28 +585,42 @@ int cap_inode_setxattr(struct dentry *dentry, const char *name,
 		if (!capable(CAP_SETFCAP))
 			return -EPERM;
 		return 0;
-	} else if (!strncmp(name, XATTR_SECURITY_PREFIX,
+	}
+
+	if (!strncmp(name, XATTR_SECURITY_PREFIX,
 		     sizeof(XATTR_SECURITY_PREFIX) - 1)  &&
 	    !capable(CAP_SYS_ADMIN))
 		return -EPERM;
 	return 0;
 }
 
+/**
+ * cap_inode_removexattr - Determine whether an xattr may be removed
+ * @dentry: The inode/dentry being altered
+ * @name: The name of the xattr to be changed
+ *
+ * Determine whether an xattr may be removed from an inode, returning 0 if
+ * permission is granted, -ve if denied.
+ *
+ * This is used to make sure security xattrs don't get removed by those who
+ * aren't privileged to remove them.
+ */
 int cap_inode_removexattr(struct dentry *dentry, const char *name)
 {
 	if (!strcmp(name, XATTR_NAME_CAPS)) {
 		if (!capable(CAP_SETFCAP))
 			return -EPERM;
 		return 0;
-	} else if (!strncmp(name, XATTR_SECURITY_PREFIX,
+	}
+
+	if (!strncmp(name, XATTR_SECURITY_PREFIX,
 		     sizeof(XATTR_SECURITY_PREFIX) - 1)  &&
 	    !capable(CAP_SYS_ADMIN))
 		return -EPERM;
 	return 0;
 }
 
-/* moved from kernel/sys.c. */
-/* 
+/*
  * cap_emulate_setxuid() fixes the effective / permitted capabilities of
  * a process after a call to setuid, setreuid, or setresuid.
  *
@@ -453,10 +634,10 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
  *  3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
  *  capabilities are set to the permitted capabilities.
  *
- *  fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should 
+ *  fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
  *  never happen.
  *
- *  -astor 
+ *  -astor
  *
  * cevans - New behaviour, Oct '99
  * A process may, via prctl(), elect to keep its capabilities when it
@@ -468,61 +649,60 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
  * files..
  * Thanks to Olaf Kirch and Peter Benie for spotting this.
  */
-static inline void cap_emulate_setxuid (int old_ruid, int old_euid,
-					int old_suid)
+static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
 {
-	if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
-	    (current->uid != 0 && current->euid != 0 && current->suid != 0) &&
+	if ((old->uid == 0 || old->euid == 0 || old->suid == 0) &&
+	    (new->uid != 0 && new->euid != 0 && new->suid != 0) &&
 	    !issecure(SECURE_KEEP_CAPS)) {
-		cap_clear (current->cap_permitted);
-		cap_clear (current->cap_effective);
-	}
-	if (old_euid == 0 && current->euid != 0) {
-		cap_clear (current->cap_effective);
-	}
-	if (old_euid != 0 && current->euid == 0) {
-		current->cap_effective = current->cap_permitted;
+		cap_clear(new->cap_permitted);
+		cap_clear(new->cap_effective);
 	}
+	if (old->euid == 0 && new->euid != 0)
+		cap_clear(new->cap_effective);
+	if (old->euid != 0 && new->euid == 0)
+		new->cap_effective = new->cap_permitted;
 }
 
-int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
-			  int flags)
+/**
+ * cap_task_fix_setuid - Fix up the results of setuid() call
+ * @new: The proposed credentials
+ * @old: The current task's current credentials
+ * @flags: Indications of what has changed
+ *
+ * Fix up the results of setuid() call before the credential changes are
+ * actually applied, returning 0 to grant the changes, -ve to deny them.
+ */
+int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
 {
 	switch (flags) {
 	case LSM_SETID_RE:
 	case LSM_SETID_ID:
 	case LSM_SETID_RES:
-		/* Copied from kernel/sys.c:setreuid/setuid/setresuid. */
-		if (!issecure (SECURE_NO_SETUID_FIXUP)) {
-			cap_emulate_setxuid (old_ruid, old_euid, old_suid);
-		}
+		/* juggle the capabilities to follow [RES]UID changes unless
+		 * otherwise suppressed */
+		if (!issecure(SECURE_NO_SETUID_FIXUP))
+			cap_emulate_setxuid(new, old);
 		break;
-	case LSM_SETID_FS:
-		{
-			uid_t old_fsuid = old_ruid;
 
-			/* Copied from kernel/sys.c:setfsuid. */
-
-			/*
-			 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
-			 *          if not, we might be a bit too harsh here.
-			 */
-
-			if (!issecure (SECURE_NO_SETUID_FIXUP)) {
-				if (old_fsuid == 0 && current->fsuid != 0) {
-					current->cap_effective =
-						cap_drop_fs_set(
-						    current->cap_effective);
-				}
-				if (old_fsuid != 0 && current->fsuid == 0) {
-					current->cap_effective =
-						cap_raise_fs_set(
-						    current->cap_effective,
-						    current->cap_permitted);
-				}
-			}
-			break;
+	case LSM_SETID_FS:
+		/* juggle the capabilties to follow FSUID changes, unless
+		 * otherwise suppressed
+		 *
+		 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
+		 *          if not, we might be a bit too harsh here.
+		 */
+		if (!issecure(SECURE_NO_SETUID_FIXUP)) {
+			if (old->fsuid == 0 && new->fsuid != 0)
+				new->cap_effective =
+					cap_drop_fs_set(new->cap_effective);
+
+			if (old->fsuid != 0 && new->fsuid == 0)
+				new->cap_effective =
+					cap_raise_fs_set(new->cap_effective,
+							 new->cap_permitted);
 		}
+		break;
+
 	default:
 		return -EINVAL;
 	}
@@ -543,42 +723,71 @@ int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
  */
 static int cap_safe_nice(struct task_struct *p)
 {
-	if (!cap_issubset(p->cap_permitted, current->cap_permitted) &&
-	    !capable(CAP_SYS_NICE))
+	int is_subset;
+
+	rcu_read_lock();
+	is_subset = cap_issubset(__task_cred(p)->cap_permitted,
+				 current_cred()->cap_permitted);
+	rcu_read_unlock();
+
+	if (!is_subset && !capable(CAP_SYS_NICE))
 		return -EPERM;
 	return 0;
 }
 
-int cap_task_setscheduler (struct task_struct *p, int policy,
+/**
+ * cap_task_setscheduler - Detemine if scheduler policy change is permitted
+ * @p: The task to affect
+ * @policy: The policy to effect
+ * @lp: The parameters to the scheduling policy
+ *
+ * Detemine if the requested scheduler policy change is permitted for the
+ * specified task, returning 0 if permission is granted, -ve if denied.
+ */
+int cap_task_setscheduler(struct task_struct *p, int policy,
 			   struct sched_param *lp)
 {
 	return cap_safe_nice(p);
 }
 
-int cap_task_setioprio (struct task_struct *p, int ioprio)
+/**
+ * cap_task_ioprio - Detemine if I/O priority change is permitted
+ * @p: The task to affect
+ * @ioprio: The I/O priority to set
+ *
+ * Detemine if the requested I/O priority change is permitted for the specified
+ * task, returning 0 if permission is granted, -ve if denied.
+ */
+int cap_task_setioprio(struct task_struct *p, int ioprio)
 {
 	return cap_safe_nice(p);
 }
 
-int cap_task_setnice (struct task_struct *p, int nice)
+/**
+ * cap_task_ioprio - Detemine if task priority change is permitted
+ * @p: The task to affect
+ * @nice: The nice value to set
+ *
+ * Detemine if the requested task priority change is permitted for the
+ * specified task, returning 0 if permission is granted, -ve if denied.
+ */
+int cap_task_setnice(struct task_struct *p, int nice)
 {
 	return cap_safe_nice(p);
 }
 
 /*
- * called from kernel/sys.c for prctl(PR_CABSET_DROP)
- * done without task_capability_lock() because it introduces
- * no new races - i.e. only another task doing capget() on
- * this task could get inconsistent info.  There can be no
- * racing writer bc a task can only change its own caps.
+ * Implement PR_CAPBSET_DROP.  Attempt to remove the specified capability from
+ * the current task's bounding set.  Returns 0 on success, -ve on error.
  */
-static long cap_prctl_drop(unsigned long cap)
+static long cap_prctl_drop(struct cred *new, unsigned long cap)
 {
 	if (!capable(CAP_SETPCAP))
 		return -EPERM;
 	if (!cap_valid(cap))
 		return -EINVAL;
-	cap_lower(current->cap_bset, cap);
+
+	cap_lower(new->cap_bset, cap);
 	return 0;
 }
 
@@ -598,22 +807,42 @@ int cap_task_setnice (struct task_struct *p, int nice)
 }
 #endif
 
+/**
+ * cap_task_prctl - Implement process control functions for this security module
+ * @option: The process control function requested
+ * @arg2, @arg3, @arg4, @arg5: The argument data for this function
+ *
+ * Allow process control functions (sys_prctl()) to alter capabilities; may
+ * also deny access to other functions not otherwise implemented here.
+ *
+ * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
+ * here, other -ve on error.  If -ENOSYS is returned, sys_prctl() and other LSM
+ * modules will consider performing the function.
+ */
 int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
-		   unsigned long arg4, unsigned long arg5, long *rc_p)
+		   unsigned long arg4, unsigned long arg5)
 {
+	struct cred *new;
 	long error = 0;
 
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
 	switch (option) {
 	case PR_CAPBSET_READ:
+		error = -EINVAL;
 		if (!cap_valid(arg2))
-			error = -EINVAL;
-		else
-			error = !!cap_raised(current->cap_bset, arg2);
-		break;
+			goto error;
+		error = !!cap_raised(new->cap_bset, arg2);
+		goto no_change;
+
 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 	case PR_CAPBSET_DROP:
-		error = cap_prctl_drop(arg2);
-		break;
+		error = cap_prctl_drop(new, arg2);
+		if (error < 0)
+			goto error;
+		goto changed;
 
 	/*
 	 * The next four prctl's remain to assist with transitioning a
@@ -635,12 +864,12 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 	 * capability-based-privilege environment.
 	 */
 	case PR_SET_SECUREBITS:
-		if ((((current->securebits & SECURE_ALL_LOCKS) >> 1)
-		     & (current->securebits ^ arg2))                  /*[1]*/
-		    || ((current->securebits & SECURE_ALL_LOCKS
-			 & ~arg2))                                    /*[2]*/
-		    || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
-		    || (cap_capable(current, CAP_SETPCAP) != 0)) {    /*[4]*/
+		error = -EPERM;
+		if ((((new->securebits & SECURE_ALL_LOCKS) >> 1)
+		     & (new->securebits ^ arg2))			/*[1]*/
+		    || ((new->securebits & SECURE_ALL_LOCKS & ~arg2))	/*[2]*/
+		    || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS))	/*[3]*/
+		    || (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0) /*[4]*/
 			/*
 			 * [1] no changing of bits that are locked
 			 * [2] no unlocking of locks
@@ -648,65 +877,80 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			 * [4] doing anything requires privilege (go read about
 			 *     the "sendmail capabilities bug")
 			 */
-			error = -EPERM;  /* cannot change a locked bit */
-		} else {
-			current->securebits = arg2;
-		}
-		break;
+		    )
+			/* cannot change a locked bit */
+			goto error;
+		new->securebits = arg2;
+		goto changed;
+
 	case PR_GET_SECUREBITS:
-		error = current->securebits;
-		break;
+		error = new->securebits;
+		goto no_change;
 
 #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
 
 	case PR_GET_KEEPCAPS:
 		if (issecure(SECURE_KEEP_CAPS))
 			error = 1;
-		break;
+		goto no_change;
+
 	case PR_SET_KEEPCAPS:
+		error = -EINVAL;
 		if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
-			error = -EINVAL;
-		else if (issecure(SECURE_KEEP_CAPS_LOCKED))
-			error = -EPERM;
-		else if (arg2)
-			current->securebits |= issecure_mask(SECURE_KEEP_CAPS);
+			goto error;
+		error = -EPERM;
+		if (issecure(SECURE_KEEP_CAPS_LOCKED))
+			goto error;
+		if (arg2)
+			new->securebits |= issecure_mask(SECURE_KEEP_CAPS);
 		else
-			current->securebits &=
-				~issecure_mask(SECURE_KEEP_CAPS);
-		break;
+			new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+		goto changed;
 
 	default:
 		/* No functionality available - continue with default */
-		return 0;
+		error = -ENOSYS;
+		goto error;
 	}
 
 	/* Functionality provided */
-	*rc_p = error;
-	return 1;
-}
+changed:
+	return commit_creds(new);
 
-void cap_task_reparent_to_init (struct task_struct *p)
-{
-	cap_set_init_eff(p->cap_effective);
-	cap_clear(p->cap_inheritable);
-	cap_set_full(p->cap_permitted);
-	p->securebits = SECUREBITS_DEFAULT;
-	return;
+no_change:
+	error = 0;
+error:
+	abort_creds(new);
+	return error;
 }
 
-int cap_syslog (int type)
+/**
+ * cap_syslog - Determine whether syslog function is permitted
+ * @type: Function requested
+ *
+ * Determine whether the current process is permitted to use a particular
+ * syslog function, returning 0 if permission is granted, -ve if not.
+ */
+int cap_syslog(int type)
 {
 	if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))
 		return -EPERM;
 	return 0;
 }
 
+/**
+ * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
+ * @mm: The VM space in which the new mapping is to be made
+ * @pages: The size of the mapping
+ *
+ * Determine whether the allocation of a new virtual mapping by the current
+ * task is permitted, returning 0 if permission is granted, -ve if not.
+ */
 int cap_vm_enough_memory(struct mm_struct *mm, long pages)
 {
 	int cap_sys_admin = 0;
 
-	if (cap_capable(current, CAP_SYS_ADMIN) == 0)
+	if (cap_capable(current, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0)
 		cap_sys_admin = 1;
 	return __vm_enough_memory(mm, pages, cap_sys_admin);
 }
-