-/* Common capabilities, needed by capability.o and root_plug.o
+/* Common capabilities, needed by capability.o.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#include <linux/sched.h>
#include <linux/prctl.h>
#include <linux/securebits.h>
+#include <linux/user_namespace.h>
+#include <linux/binfmts.h>
+#include <linux/personality.h>
-int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
-{
- NETLINK_CB(skb).eff_cap = current_cap();
- return 0;
+/*
+ * If a non-root user executes a setuid-root binary in
+ * !secure(SECURE_NOROOT) mode, then we raise capabilities.
+ * However if fE is also set, then the intent is for only
+ * the file capabilities to be applied, and the setuid-root
+ * bit is left on either to change the uid (plausible) or
+ * to get full privilege on a kernel without file capabilities
+ * support. So in that case we do not raise capabilities.
+ *
+ * Warn if that happens, once per boot.
+ */
+static void warn_setuid_and_fcaps_mixed(const char *fname)
+{
+ static int warned;
+ if (!warned) {
+ printk(KERN_INFO "warning: `%s' has both setuid-root and"
+ " effective capabilities. Therefore not raising all"
+ " capabilities.\n", fname);
+ warned = 1;
+ }
}
-int cap_netlink_recv(struct sk_buff *skb, int cap)
+int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
{
- if (!cap_raised(NETLINK_CB(skb).eff_cap, 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
+ * @cred: The credentials to use
+ * @ns: The user namespace in which we need the capability
* @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.
+ * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable()
+ * and has_capability() functions. That is, it has the reverse semantics:
+ * cap_has_capability() returns 0 when a task has a capability, but the
+ * kernel's capable() and has_capability() returns 1 for this case.
*/
-int cap_capable(struct task_struct *tsk, int cap, int audit)
+int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
+ int cap, int audit)
{
- __u32 cap_raised;
+ for (;;) {
+ /* The creator of the user namespace has all caps. */
+ if (targ_ns != &init_user_ns && targ_ns->creator == cred->user)
+ return 0;
- /* Derived from include/linux/sched.h:capable. */
- rcu_read_lock();
- cap_raised = cap_raised(__task_cred(tsk)->cap_effective, cap);
- rcu_read_unlock();
- return cap_raised ? 0 : -EPERM;
+ /* Do we have the necessary capabilities? */
+ if (targ_ns == cred->user->user_ns)
+ return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
+
+ /* Have we tried all of the parent namespaces? */
+ if (targ_ns == &init_user_ns)
+ return -EPERM;
+
+ /*
+ *If you have a capability in a parent user ns, then you have
+ * it over all children user namespaces as well.
+ */
+ targ_ns = targ_ns->creator->user_ns;
+ }
+
+ /* We never get here */
}
/**
* 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)
+int cap_settime(const struct timespec *ts, const struct timezone *tz)
{
if (!capable(CAP_SYS_TIME))
return -EPERM;
}
/**
- * cap_ptrace_may_access - Determine whether the current process may access
+ * cap_ptrace_access_check - Determine whether the current process may access
* another
* @child: The process to be accessed
* @mode: The mode of attachment.
*
+ * If we are in the same or an ancestor user_ns and have all the target
+ * task's capabilities, then ptrace access is allowed.
+ * If we have the ptrace capability to the target user_ns, then ptrace
+ * access is allowed.
+ * Else denied.
+ *
* 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)
+int cap_ptrace_access_check(struct task_struct *child, unsigned int mode)
{
int ret = 0;
+ const struct cred *cred, *child_cred;
rcu_read_lock();
- if (!cap_issubset(__task_cred(child)->cap_permitted,
- current_cred()->cap_permitted) &&
- !capable(CAP_SYS_PTRACE))
- ret = -EPERM;
+ cred = current_cred();
+ child_cred = __task_cred(child);
+ if (cred->user->user_ns == child_cred->user->user_ns &&
+ cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
+ goto out;
+ if (ns_capable(child_cred->user->user_ns, CAP_SYS_PTRACE))
+ goto out;
+ ret = -EPERM;
+out:
rcu_read_unlock();
return ret;
}
* cap_ptrace_traceme - Determine whether another process may trace the current
* @parent: The task proposed to be the tracer
*
+ * If parent is in the same or an ancestor user_ns and has all current's
+ * capabilities, then ptrace access is allowed.
+ * If parent has the ptrace capability to current's user_ns, then ptrace
+ * access is allowed.
+ * Else denied.
+ *
* 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)
{
int ret = 0;
+ const struct cred *cred, *child_cred;
rcu_read_lock();
- if (!cap_issubset(current_cred()->cap_permitted,
- __task_cred(parent)->cap_permitted) &&
- !has_capability(parent, CAP_SYS_PTRACE))
- ret = -EPERM;
+ cred = __task_cred(parent);
+ child_cred = current_cred();
+ if (cred->user->user_ns == child_cred->user->user_ns &&
+ cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
+ goto out;
+ if (has_ns_capability(parent, child_cred->user->user_ns, CAP_SYS_PTRACE))
+ goto out;
+ ret = -EPERM;
+out:
rcu_read_unlock();
return ret;
}
*/
static inline int cap_inh_is_capped(void)
{
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
/* they are so limited unless the current task has the CAP_SETPCAP
* capability
*/
- if (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
+ if (cap_capable(current_cred(), current_cred()->user->user_ns,
+ CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
return 0;
-#endif
return 1;
}
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
struct inode *inode = dentry->d_inode;
int error;
- if (!inode->i_op || !inode->i_op->getxattr)
+ if (!inode->i_op->getxattr)
return 0;
error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
{
struct inode *inode = dentry->d_inode;
- if (!inode->i_op || !inode->i_op->removexattr)
+ if (!inode->i_op->removexattr)
return 0;
return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
*/
static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
struct linux_binprm *bprm,
- bool *effective)
+ bool *effective,
+ bool *has_cap)
{
struct cred *new = bprm->cred;
unsigned i;
if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
*effective = true;
+ if (caps->magic_etc & VFS_CAP_REVISION_MASK)
+ *has_cap = true;
+
CAP_FOR_EACH_U32(i) {
__u32 permitted = caps->permitted.cap[i];
__u32 inheritable = caps->inheritable.cap[i];
memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
- if (!inode || !inode->i_op || !inode->i_op->getxattr)
+ if (!inode || !inode->i_op->getxattr)
return -ENODATA;
size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
* 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)
+static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_cap)
{
struct dentry *dentry;
int rc = 0;
goto out;
}
- rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective);
+ rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective, has_cap);
if (rc == -EINVAL)
printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
__func__, rc, bprm->filename);
return rc;
}
-#else
-int cap_inode_need_killpriv(struct dentry *dentry)
-{
- return 0;
-}
-
-int cap_inode_killpriv(struct dentry *dentry)
-{
- return 0;
-}
-
-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
-
-/*
- * 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
{
const struct cred *old = current_cred();
struct cred *new = bprm->cred;
- bool effective;
+ bool effective, has_cap = false;
int ret;
effective = false;
- ret = get_file_caps(bprm, &effective);
+ ret = get_file_caps(bprm, &effective, &has_cap);
if (ret < 0)
return ret;
if (!issecure(SECURE_NOROOT)) {
/*
+ * If the legacy file capability is set, then don't set privs
+ * for a setuid root binary run by a non-root user. Do set it
+ * for a root user just to cause least surprise to an admin.
+ */
+ if (has_cap && new->uid != 0 && new->euid == 0) {
+ warn_setuid_and_fcaps_mixed(bprm->filename);
+ goto skip;
+ }
+ /*
* To support inheritance of root-permissions and suid-root
* executables under compatibility mode, we override the
* capability sets for the file.
if (new->euid == 0)
effective = true;
}
+skip:
+
+ /* if we have fs caps, clear dangerous personality flags */
+ if (!cap_issubset(new->cap_permitted, old->cap_permitted))
+ bprm->per_clear |= PER_CLEAR_ON_SETID;
+
/* Don't let someone trace a set[ug]id/setpcap binary with the revised
* credentials unless they have the appropriate permit
new->euid = new->uid;
new->egid = new->gid;
}
- if (cap_limit_ptraced_target())
- new->cap_permitted = cap_intersect(new->cap_permitted,
- old->cap_permitted);
+ new->cap_permitted = cap_intersect(new->cap_permitted,
+ old->cap_permitted);
}
new->suid = new->fsuid = new->euid;
new->sgid = new->fsgid = new->egid;
- /* 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)) {
- if (effective)
- new->cap_effective = new->cap_permitted;
- else
- cap_clear(new->cap_effective);
- }
+ if (effective)
+ new->cap_effective = new->cap_permitted;
+ else
+ cap_clear(new->cap_effective);
bprm->cap_effective = effective;
/*
}
if (!strncmp(name, XATTR_SECURITY_PREFIX,
- sizeof(XATTR_SECURITY_PREFIX) - 1) &&
+ sizeof(XATTR_SECURITY_PREFIX) - 1) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
return 0;
}
if (!strncmp(name, XATTR_SECURITY_PREFIX,
- sizeof(XATTR_SECURITY_PREFIX) - 1) &&
+ sizeof(XATTR_SECURITY_PREFIX) - 1) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
return 0;
return 0;
}
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
/*
* Rationale: code calling task_setscheduler, task_setioprio, and
* task_setnice, assumes that
/**
* 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)
+int cap_task_setscheduler(struct task_struct *p)
{
return cap_safe_nice(p);
}
return 0;
}
-#else
-int cap_task_setscheduler (struct task_struct *p, int policy,
- struct sched_param *lp)
-{
- return 0;
-}
-int cap_task_setioprio (struct task_struct *p, int ioprio)
-{
- return 0;
-}
-int cap_task_setnice (struct task_struct *p, int nice)
-{
- return 0;
-}
-#endif
-
/**
* cap_task_prctl - Implement process control functions for this security module
* @option: The process control function requested
error = !!cap_raised(new->cap_bset, arg2);
goto no_change;
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
case PR_CAPBSET_DROP:
error = cap_prctl_drop(new, arg2);
if (error < 0)
& (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]*/
+ || (cap_capable(current_cred(),
+ current_cred()->user->user_ns, CAP_SETPCAP,
+ SECURITY_CAP_AUDIT) != 0) /*[4]*/
/*
* [1] no changing of bits that are locked
* [2] no unlocking of locks
error = new->securebits;
goto no_change;
-#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
-
case PR_GET_KEEPCAPS:
if (issecure(SECURE_KEEP_CAPS))
error = 1;
return commit_creds(new);
no_change:
- error = 0;
error:
abort_creds(new);
return error;
}
/**
- * 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
{
int cap_sys_admin = 0;
- if (cap_capable(current, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0)
+ if (cap_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN,
+ SECURITY_CAP_NOAUDIT) == 0)
cap_sys_admin = 1;
return __vm_enough_memory(mm, pages, cap_sys_admin);
}
+
+/*
+ * cap_file_mmap - check if able to map given addr
+ * @file: unused
+ * @reqprot: unused
+ * @prot: unused
+ * @flags: unused
+ * @addr: address attempting to be mapped
+ * @addr_only: unused
+ *
+ * If the process is attempting to map memory below dac_mmap_min_addr they need
+ * CAP_SYS_RAWIO. The other parameters to this function are unused by the
+ * capability security module. Returns 0 if this mapping should be allowed
+ * -EPERM if not.
+ */
+int cap_file_mmap(struct file *file, unsigned long reqprot,
+ unsigned long prot, unsigned long flags,
+ unsigned long addr, unsigned long addr_only)
+{
+ int ret = 0;
+
+ if (addr < dac_mmap_min_addr) {
+ ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO,
+ SECURITY_CAP_AUDIT);
+ /* set PF_SUPERPRIV if it turns out we allow the low mmap */
+ if (ret == 0)
+ current->flags |= PF_SUPERPRIV;
+ }
+ return ret;
+}
projects / linux-flexiantxendom0-3.2.10.git / blobdiff