/* Common capabilities, needed by capability.o and root_plug.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 *	the Free Software Foundation; either version 2 of the License, or *	(at your option) any later version. * */ #include <linux/capability.h>#include <linux/module.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/security.h>#include <linux/file.h>#include <linux/mm.h>#include <linux/mman.h>#include <linux/pagemap.h>#include <linux/swap.h>#include <linux/smp_lock.h>#include <linux/skbuff.h>#include <linux/netlink.h>#include <linux/ptrace.h>#include <linux/xattr.h>#include <linux/hugetlb.h> int cap_netlink_send(struct sock *sk, struct sk_buff *skb){	NETLINK_CB(skb).eff_cap = current->cap_effective;	return 0;} EXPORT_SYMBOL(cap_netlink_send); int cap_netlink_recv(struct sk_buff *skb, int cap){	if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))		return -EPERM;	return 0;} EXPORT_SYMBOL(cap_netlink_recv); int cap_capable (struct task_struct *tsk, int cap){	/* Derived from include/linux/sched.h:capable. */	if (cap_raised(tsk->cap_effective, cap))		return 0;	return -EPERM;} int cap_settime(struct timespec *ts, struct timezone *tz){	if (!capable(CAP_SYS_TIME))		return -EPERM;	return 0;} int cap_ptrace (struct task_struct *parent, struct task_struct *child){	/* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */	if (!cap_issubset(child->cap_permitted, parent->cap_permitted) &&	    !__capable(parent, CAP_SYS_PTRACE))		return -EPERM;	return 0;} int cap_capget (struct task_struct *target, kernel_cap_t *effective,		kernel_cap_t *inheritable, kernel_cap_t *permitted){	/* Derived from kernel/capability.c:sys_capget. */	*effective = cap_t (target->cap_effective);	*inheritable = cap_t (target->cap_inheritable);	*permitted = cap_t (target->cap_permitted);	return 0;} int cap_capset_check (struct task_struct *target, kernel_cap_t *effective,		      kernel_cap_t *inheritable, kernel_cap_t *permitted){	/* Derived from kernel/capability.c:sys_capset. */	/* verify restrictions on target's new Inheritable set */	if (!cap_issubset (*inheritable,			   cap_combine (target->cap_inheritable,					current->cap_permitted))) {		return -EPERM;	} 	/* verify restrictions on target's new Permitted set */	if (!cap_issubset (*permitted,			   cap_combine (target->cap_permitted,					current->cap_permitted))) {		return -EPERM;	} 	/* verify the _new_Effective_ is a subset of the _new_Permitted_ */	if (!cap_issubset (*effective, *permitted)) {		return -EPERM;	} 	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;} int cap_bprm_set_security (struct linux_binprm *bprm){	/* Copied from fs/exec.c:prepare_binprm. */ 	/* We don't have VFS support for capabilities yet */	cap_clear (bprm->cap_inheritable);	cap_clear (bprm->cap_permitted);	cap_clear (bprm->cap_effective); 	/*  To support inheritance of root-permissions and suid-root	 *  executables under compatibility mode, we raise all three	 *  capability sets for the file.	 *	 *  If only the real uid is 0, we only raise the inheritable	 *  and permitted sets of the executable file.	 */ 	if (!issecure (SECURE_NOROOT)) {		if (bprm->e_uid == 0 || current->uid == 0) {			cap_set_full (bprm->cap_inheritable);			cap_set_full (bprm->cap_permitted);		}		if (bprm->e_uid == 0)			cap_set_full (bprm->cap_effective);	}	return 0;} void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe){	/* Derived from fs/exec.c:compute_creds. */	kernel_cap_t new_permitted, working; 	new_permitted = cap_intersect (bprm->cap_permitted, cap_bset);	working = cap_intersect (bprm->cap_inheritable,				 current->cap_inheritable);	new_permitted = cap_combine (new_permitted, working); 	if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||	    !cap_issubset (new_permitted, current->cap_permitted)) {		current->mm->dumpable = suid_dumpable; 		if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {			if (!capable(CAP_SETUID)) {				bprm->e_uid = current->uid;				bprm->e_gid = current->gid;			}			if (!capable (CAP_SETPCAP)) {				new_permitted = cap_intersect (new_permitted,							current->cap_permitted);			}		}	} 	current->suid = current->euid = current->fsuid = bprm->e_uid;	current->sgid = current->egid = current->fsgid = bprm->e_gid; 	/* For init, we want to retain the capabilities set	 * in the init_task struct. Thus we skip the usual	 * capability rules */	if (!is_init(current)) {		current->cap_permitted = new_permitted;		current->cap_effective =		    cap_intersect (new_permitted, bprm->cap_effective);	} 	/* AUD: Audit candidate if current->cap_effective is set */ 	current->keep_capabilities = 0;} int cap_bprm_secureexec (struct linux_binprm *bprm){	/* If/when this module is enhanced to incorporate capability	   bits on files, the test below should be extended to also perform a 	   test between the old and new capability sets.  For now,	   it simply preserves the legacy decision algorithm used by	   the old userland. */	return (current->euid != current->uid ||		current->egid != current->gid);} int cap_inode_setxattr(struct dentry *dentry, char *name, void *value,		       size_t size, int flags){	if (!strncmp(name, XATTR_SECURITY_PREFIX,		     sizeof(XATTR_SECURITY_PREFIX) - 1)  &&	    !capable(CAP_SYS_ADMIN))		return -EPERM;	return 0;} int cap_inode_removexattr(struct dentry *dentry, char *name){	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. * *  1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of *  {r,e,s}uid != 0, the permitted and effective capabilities are *  cleared. * *  2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective *  capabilities of the process are cleared. * *  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  *  never happen. * *  -astor  * * cevans - New behaviour, Oct '99 * A process may, via prctl(), elect to keep its capabilities when it * calls setuid() and switches away from uid==0. Both permitted and * effective sets will be retained. * Without this change, it was impossible for a daemon to drop only some * of its privilege. The call to setuid(!=0) would drop all privileges! * Keeping uid 0 is not an option because uid 0 owns too many vital * 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){	if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&	    (current->uid != 0 && current->euid != 0 && current->suid != 0) &&	    !current->keep_capabilities) {		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;	}} int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,			  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);		}		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) {					cap_t (current->cap_effective) &=					    ~CAP_FS_MASK;				}				if (old_fsuid != 0 && current->fsuid == 0) {					cap_t (current->cap_effective) |=					    (cap_t (current->cap_permitted) &					     CAP_FS_MASK);				}			}			break;		}	default:		return -EINVAL;	} 	return 0;} void cap_task_reparent_to_init (struct task_struct *p){	p->cap_effective = CAP_INIT_EFF_SET;	p->cap_inheritable = CAP_INIT_INH_SET;	p->cap_permitted = CAP_FULL_SET;	p->keep_capabilities = 0;	return;} int cap_syslog (int type){	if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))		return -EPERM;	return 0;} int cap_vm_enough_memory(long pages){	int cap_sys_admin = 0; 	if (cap_capable(current, CAP_SYS_ADMIN) == 0)		cap_sys_admin = 1;	return __vm_enough_memory(pages, cap_sys_admin);} EXPORT_SYMBOL(cap_capable);EXPORT_SYMBOL(cap_settime);EXPORT_SYMBOL(cap_ptrace);EXPORT_SYMBOL(cap_capget);EXPORT_SYMBOL(cap_capset_check);EXPORT_SYMBOL(cap_capset_set);EXPORT_SYMBOL(cap_bprm_set_security);EXPORT_SYMBOL(cap_bprm_apply_creds);EXPORT_SYMBOL(cap_bprm_secureexec);EXPORT_SYMBOL(cap_inode_setxattr);EXPORT_SYMBOL(cap_inode_removexattr);EXPORT_SYMBOL(cap_task_post_setuid);EXPORT_SYMBOL(cap_task_reparent_to_init);EXPORT_SYMBOL(cap_syslog);EXPORT_SYMBOL(cap_vm_enough_memory); MODULE_DESCRIPTION("Standard Linux Common Capabilities Security Module");MODULE_LICENSE("GPL");