#include <linux/prctl.h>
#include <linux/securebits.h>
+/*
+ * 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(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_send(struct sock *sk, struct sk_buff *skb)
{
NETLINK_CB(skb).eff_cap = current_cap();
EXPORT_SYMBOL(cap_netlink_recv);
/**
- * cap_capable - Determine whether current has a particular effective 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 that
- * this uses current's subjective/effective credentials.
- *
- * 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.
- */
-int cap_capable(int cap, int audit)
-{
- return cap_raised(current_cap(), cap) ? 0 : -EPERM;
-}
-
-/**
- * cap_has_capability - Determine whether a task has a particular effective capability
+ * cap_capable - Determine whether a task has a particular effective capability
* @tsk: The task to query
* @cred: The credentials to use
* @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 that
- * this uses the task's objective/real credentials.
+ * its effective set, returning 0 if it does, -ve if it does not.
*
- * NOTE WELL: cap_has_capability() cannot be used like the kernel's
- * has_capability() function. That is, it has the reverse semantics:
+ * 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 has_capability() returns 1 for this case.
+ * kernel's capable() and has_capability() returns 1 for this case.
*/
-int cap_task_capable(struct task_struct *tsk, const struct cred *cred, int cap,
- int audit)
+int cap_capable(struct task_struct *tsk, const struct cred *cred, int cap,
+ int audit)
{
return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
}
/* they are so limited unless the current task has the CAP_SETPCAP
* capability
*/
- if (cap_capable(CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
+ if (cap_capable(current, current_cred(), CAP_SETPCAP,
+ SECURITY_CAP_AUDIT) == 0)
return 0;
#endif
return 1;
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);
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,
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 (effective && 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:
/* Don't let someone trace a set[ug]id/setpcap binary with the revised
* credentials unless they have the appropriate permit
& (new->securebits ^ arg2)) /*[1]*/
|| ((new->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/
|| (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
- || (cap_capable(CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0) /*[4]*/
+ || (cap_capable(current, current_cred(), CAP_SETPCAP,
+ SECURITY_CAP_AUDIT) != 0) /*[4]*/
/*
* [1] no changing of bits that are locked
* [2] no unlocking of locks
return commit_creds(new);
no_change:
- error = 0;
error:
abort_creds(new);
return error;
{
int cap_sys_admin = 0;
- if (cap_capable(CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0)
+ if (cap_capable(current, current_cred(), CAP_SYS_ADMIN,
+ SECURITY_CAP_NOAUDIT) == 0)
cap_sys_admin = 1;
return __vm_enough_memory(mm, pages, cap_sys_admin);
}