From 83d498569e9a7a4b92c4c5d3566f2d6a604f28c9 Mon Sep 17 00:00:00 2001
From: Eric Paris <eparis@redhat.com>
Date: Wed, 4 Apr 2012 13:45:40 -0400
Subject: SELinux: rename dentry_open to file_open

dentry_open takes a file, rename it to file_open

Signed-off-by: Eric Paris <eparis@redhat.com>
---
 include/linux/security.h | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

(limited to 'include/linux/security.h')

diff --git a/include/linux/security.h b/include/linux/security.h
index 673afbb8238a..de412ea29aac 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -639,10 +639,7 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *	to receive an open file descriptor via socket IPC.
  *	@file contains the file structure being received.
  *	Return 0 if permission is granted.
- *
- * Security hook for dentry
- *
- * @dentry_open
+ * @file_open
  *	Save open-time permission checking state for later use upon
  *	file_permission, and recheck access if anything has changed
  *	since inode_permission.
@@ -1497,7 +1494,7 @@ struct security_operations {
 	int (*file_send_sigiotask) (struct task_struct *tsk,
 				    struct fown_struct *fown, int sig);
 	int (*file_receive) (struct file *file);
-	int (*dentry_open) (struct file *file, const struct cred *cred);
+	int (*file_open) (struct file *file, const struct cred *cred);
 
 	int (*task_create) (unsigned long clone_flags);
 	void (*task_free) (struct task_struct *task);
@@ -1756,7 +1753,7 @@ int security_file_set_fowner(struct file *file);
 int security_file_send_sigiotask(struct task_struct *tsk,
 				 struct fown_struct *fown, int sig);
 int security_file_receive(struct file *file);
-int security_dentry_open(struct file *file, const struct cred *cred);
+int security_file_open(struct file *file, const struct cred *cred);
 int security_task_create(unsigned long clone_flags);
 void security_task_free(struct task_struct *task);
 int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
@@ -2227,8 +2224,8 @@ static inline int security_file_receive(struct file *file)
 	return 0;
 }
 
-static inline int security_dentry_open(struct file *file,
-				       const struct cred *cred)
+static inline int security_file_open(struct file *file,
+				     const struct cred *cred)
 {
 	return 0;
 }
-- 
cgit v1.3-8-gc7d7


From 259e5e6c75a910f3b5e656151dc602f53f9d7548 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@amacapital.net>
Date: Thu, 12 Apr 2012 16:47:50 -0500
Subject: Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs

With this change, calling
  prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
disables privilege granting operations at execve-time.  For example, a
process will not be able to execute a setuid binary to change their uid
or gid if this bit is set.  The same is true for file capabilities.

Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that
LSMs respect the requested behavior.

To determine if the NO_NEW_PRIVS bit is set, a task may call
  prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
It returns 1 if set and 0 if it is not set. If any of the arguments are
non-zero, it will return -1 and set errno to -EINVAL.
(PR_SET_NO_NEW_PRIVS behaves similarly.)

This functionality is desired for the proposed seccomp filter patch
series.  By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the
system call behavior for itself and its child tasks without being
able to impact the behavior of a more privileged task.

Another potential use is making certain privileged operations
unprivileged.  For example, chroot may be considered "safe" if it cannot
affect privileged tasks.

Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is
set and AppArmor is in use.  It is fixed in a subsequent patch.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>

v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: James Morris <james.l.morris@oracle.com>
---
 fs/exec.c                  | 10 +++++++++-
 include/linux/prctl.h      | 15 +++++++++++++++
 include/linux/sched.h      |  2 ++
 include/linux/security.h   |  1 +
 kernel/sys.c               | 10 ++++++++++
 security/apparmor/domain.c |  4 ++++
 security/commoncap.c       |  7 +++++--
 security/selinux/hooks.c   | 10 +++++++++-
 8 files changed, 55 insertions(+), 4 deletions(-)

(limited to 'include/linux/security.h')

diff --git a/fs/exec.c b/fs/exec.c
index b1fd2025e59a..d038968b54b4 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1245,6 +1245,13 @@ static int check_unsafe_exec(struct linux_binprm *bprm)
 			bprm->unsafe |= LSM_UNSAFE_PTRACE;
 	}
 
+	/*
+	 * This isn't strictly necessary, but it makes it harder for LSMs to
+	 * mess up.
+	 */
+	if (current->no_new_privs)
+		bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
+
 	n_fs = 1;
 	spin_lock(&p->fs->lock);
 	rcu_read_lock();
@@ -1288,7 +1295,8 @@ int prepare_binprm(struct linux_binprm *bprm)
 	bprm->cred->euid = current_euid();
 	bprm->cred->egid = current_egid();
 
-	if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
+	if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) &&
+	    !current->no_new_privs) {
 		/* Set-uid? */
 		if (mode & S_ISUID) {
 			bprm->per_clear |= PER_CLEAR_ON_SETID;
diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index e0cfec2490aa..78b76e24cc7e 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -124,4 +124,19 @@
 #define PR_SET_CHILD_SUBREAPER 36
 #define PR_GET_CHILD_SUBREAPER 37
 
+/*
+ * If no_new_privs is set, then operations that grant new privileges (i.e.
+ * execve) will either fail or not grant them.  This affects suid/sgid,
+ * file capabilities, and LSMs.
+ *
+ * Operations that merely manipulate or drop existing privileges (setresuid,
+ * capset, etc.) will still work.  Drop those privileges if you want them gone.
+ *
+ * Changing LSM security domain is considered a new privilege.  So, for example,
+ * asking selinux for a specific new context (e.g. with runcon) will result
+ * in execve returning -EPERM.
+ */
+#define PR_SET_NO_NEW_PRIVS 38
+#define PR_GET_NO_NEW_PRIVS 39
+
 #endif /* _LINUX_PRCTL_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 81a173c0897d..ba60897bb447 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1341,6 +1341,8 @@ struct task_struct {
 				 * execve */
 	unsigned in_iowait:1;
 
+	/* task may not gain privileges */
+	unsigned no_new_privs:1;
 
 	/* Revert to default priority/policy when forking */
 	unsigned sched_reset_on_fork:1;
diff --git a/include/linux/security.h b/include/linux/security.h
index 673afbb8238a..6e1dea93907a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -144,6 +144,7 @@ struct request_sock;
 #define LSM_UNSAFE_SHARE	1
 #define LSM_UNSAFE_PTRACE	2
 #define LSM_UNSAFE_PTRACE_CAP	4
+#define LSM_UNSAFE_NO_NEW_PRIVS	8
 
 #ifdef CONFIG_MMU
 extern int mmap_min_addr_handler(struct ctl_table *table, int write,
diff --git a/kernel/sys.c b/kernel/sys.c
index e7006eb6c1e4..b82568b7d201 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1979,6 +1979,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 			error = put_user(me->signal->is_child_subreaper,
 					 (int __user *) arg2);
 			break;
+		case PR_SET_NO_NEW_PRIVS:
+			if (arg2 != 1 || arg3 || arg4 || arg5)
+				return -EINVAL;
+
+			current->no_new_privs = 1;
+			break;
+		case PR_GET_NO_NEW_PRIVS:
+			if (arg2 || arg3 || arg4 || arg5)
+				return -EINVAL;
+			return current->no_new_privs ? 1 : 0;
 		default:
 			error = -EINVAL;
 			break;
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 6327685c101e..18c88d06e881 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -360,6 +360,10 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
 	if (bprm->cred_prepared)
 		return 0;
 
+	/* XXX: no_new_privs is not usable with AppArmor yet */
+	if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)
+		return -EPERM;
+
 	cxt = bprm->cred->security;
 	BUG_ON(!cxt);
 
diff --git a/security/commoncap.c b/security/commoncap.c
index 0cf4b53480a7..edd3918fac02 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -506,14 +506,17 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
 skip:
 
 	/* Don't let someone trace a set[ug]id/setpcap binary with the revised
-	 * credentials unless they have the appropriate permit
+	 * credentials unless they have the appropriate permit.
+	 *
+	 * In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
 	 */
 	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)) {
+		if (!capable(CAP_SETUID) ||
+		    (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)) {
 			new->euid = new->uid;
 			new->egid = new->gid;
 		}
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d85b793c9321..0b06685787b9 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2016,6 +2016,13 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm)
 		new_tsec->sid = old_tsec->exec_sid;
 		/* Reset exec SID on execve. */
 		new_tsec->exec_sid = 0;
+
+		/*
+		 * Minimize confusion: if no_new_privs and a transition is
+		 * explicitly requested, then fail the exec.
+		 */
+		if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)
+			return -EPERM;
 	} else {
 		/* Check for a default transition on this program. */
 		rc = security_transition_sid(old_tsec->sid, isec->sid,
@@ -2029,7 +2036,8 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm)
 	ad.selinux_audit_data = &sad;
 	ad.u.path = bprm->file->f_path;
 
-	if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
+	if ((bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) ||
+	    (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS))
 		new_tsec->sid = old_tsec->sid;
 
 	if (new_tsec->sid == old_tsec->sid) {
-- 
cgit v1.3-8-gc7d7


From d007794a182bc072a7b7479909dbd0d67ba341be Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 30 May 2012 13:11:37 -0400
Subject: split cap_mmap_addr() out of cap_file_mmap()

... switch callers.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 include/linux/security.h   |  3 ++-
 security/apparmor/lsm.c    |  2 +-
 security/commoncap.c       | 32 +++++++++++++++++++++++---------
 security/selinux/hooks.c   |  2 +-
 security/smack/smack_lsm.c |  2 +-
 5 files changed, 28 insertions(+), 13 deletions(-)

(limited to 'include/linux/security.h')

diff --git a/include/linux/security.h b/include/linux/security.h
index ab0e091ce5fa..4ad59c9fa731 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -86,6 +86,7 @@ extern int cap_inode_setxattr(struct dentry *dentry, const char *name,
 extern int cap_inode_removexattr(struct dentry *dentry, const char *name);
 extern int cap_inode_need_killpriv(struct dentry *dentry);
 extern int cap_inode_killpriv(struct dentry *dentry);
+extern int cap_mmap_addr(unsigned long addr);
 extern int cap_file_mmap(struct file *file, unsigned long reqprot,
 			 unsigned long prot, unsigned long flags,
 			 unsigned long addr, unsigned long addr_only);
@@ -2187,7 +2188,7 @@ static inline int security_file_mmap(struct file *file, unsigned long reqprot,
 				     unsigned long addr,
 				     unsigned long addr_only)
 {
-	return cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	return cap_mmap_addr(addr);
 }
 
 static inline int security_file_mprotect(struct vm_area_struct *vma,
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 032daab449b0..8430d8937afb 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -497,7 +497,7 @@ static int apparmor_file_mmap(struct file *file, unsigned long reqprot,
 	int rc = 0;
 
 	/* do DAC check */
-	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	rc = cap_mmap_addr(addr);
 	if (rc || addr_only)
 		return rc;
 
diff --git a/security/commoncap.c b/security/commoncap.c
index e771cb1b2d79..ebac3618896e 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -958,22 +958,15 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages)
 }
 
 /*
- * cap_file_mmap - check if able to map given addr
- * @file: unused
- * @reqprot: unused
- * @prot: unused
- * @flags: unused
+ * cap_mmap_addr - check if able to map given addr
  * @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 cap_mmap_addr(unsigned long addr)
 {
 	int ret = 0;
 
@@ -986,3 +979,24 @@ int cap_file_mmap(struct file *file, unsigned long reqprot,
 	}
 	return ret;
 }
+
+/*
+ * 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)
+{
+	return cap_mmap_addr(addr);
+}
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index fa2341b68331..25c125eaa3d8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3104,7 +3104,7 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
 	}
 
 	/* do DAC check on address space usage */
-	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	rc = cap_mmap_addr(addr);
 	if (rc || addr_only)
 		return rc;
 
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d583c0545808..a62197718768 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1199,7 +1199,7 @@ static int smack_file_mmap(struct file *file,
 	int rc;
 
 	/* do DAC check on address space usage */
-	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	rc = cap_mmap_addr(addr);
 	if (rc || addr_only)
 		return rc;
 
-- 
cgit v1.3-8-gc7d7


From e5467859f7f79b69fc49004403009dfdba3bec53 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 30 May 2012 13:30:51 -0400
Subject: split ->file_mmap() into ->mmap_addr()/->mmap_file()

... i.e. file-dependent and address-dependent checks.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/exec.c                  |  4 ----
 include/linux/security.h   | 36 ++++++++++++++++++++----------------
 mm/mmap.c                  | 12 ++++++++----
 mm/mremap.c                |  4 ++--
 mm/nommu.c                 |  5 ++++-
 security/apparmor/lsm.c    | 15 ++++-----------
 security/capability.c      |  3 ++-
 security/commoncap.c       | 21 +++------------------
 security/security.c        | 12 ++++++++----
 security/selinux/hooks.c   | 15 ++++++++-------
 security/smack/smack_lsm.c | 15 +++++----------
 11 files changed, 64 insertions(+), 78 deletions(-)

(limited to 'include/linux/security.h')

diff --git a/fs/exec.c b/fs/exec.c
index 52c9e2ff6e6b..a79786a8d2c8 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -280,10 +280,6 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
 	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 	INIT_LIST_HEAD(&vma->anon_vma_chain);
 
-	err = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
-	if (err)
-		goto err;
-
 	err = insert_vm_struct(mm, vma);
 	if (err)
 		goto err;
diff --git a/include/linux/security.h b/include/linux/security.h
index 4ad59c9fa731..f1bae0963ddc 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -87,9 +87,8 @@ extern int cap_inode_removexattr(struct dentry *dentry, const char *name);
 extern int cap_inode_need_killpriv(struct dentry *dentry);
 extern int cap_inode_killpriv(struct dentry *dentry);
 extern int cap_mmap_addr(unsigned long addr);
-extern int cap_file_mmap(struct file *file, unsigned long reqprot,
-			 unsigned long prot, unsigned long flags,
-			 unsigned long addr, unsigned long addr_only);
+extern int cap_mmap_file(struct file *file, unsigned long reqprot,
+			 unsigned long prot, unsigned long flags);
 extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags);
 extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			  unsigned long arg4, unsigned long arg5);
@@ -587,15 +586,17 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *	simple integer value.  When @arg represents a user space pointer, it
  *	should never be used by the security module.
  *	Return 0 if permission is granted.
- * @file_mmap :
+ * @mmap_addr :
+ *	Check permissions for a mmap operation at @addr.
+ *	@addr contains virtual address that will be used for the operation.
+ *	Return 0 if permission is granted.
+ * @mmap_file :
  *	Check permissions for a mmap operation.  The @file may be NULL, e.g.
  *	if mapping anonymous memory.
  *	@file contains the file structure for file to map (may be NULL).
  *	@reqprot contains the protection requested by the application.
  *	@prot contains the protection that will be applied by the kernel.
  *	@flags contains the operational flags.
- *	@addr contains virtual address that will be used for the operation.
- *	@addr_only contains a boolean: 0 if file-backed VMA, otherwise 1.
  *	Return 0 if permission is granted.
  * @file_mprotect:
  *	Check permissions before changing memory access permissions.
@@ -1482,10 +1483,10 @@ struct security_operations {
 	void (*file_free_security) (struct file *file);
 	int (*file_ioctl) (struct file *file, unsigned int cmd,
 			   unsigned long arg);
-	int (*file_mmap) (struct file *file,
+	int (*mmap_addr) (unsigned long addr);
+	int (*mmap_file) (struct file *file,
 			  unsigned long reqprot, unsigned long prot,
-			  unsigned long flags, unsigned long addr,
-			  unsigned long addr_only);
+			  unsigned long flags);
 	int (*file_mprotect) (struct vm_area_struct *vma,
 			      unsigned long reqprot,
 			      unsigned long prot);
@@ -1744,9 +1745,9 @@ int security_file_permission(struct file *file, int mask);
 int security_file_alloc(struct file *file);
 void security_file_free(struct file *file);
 int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
-int security_file_mmap(struct file *file, unsigned long reqprot,
-			unsigned long prot, unsigned long flags,
-			unsigned long addr, unsigned long addr_only);
+int security_mmap_file(struct file *file, unsigned long reqprot,
+			unsigned long prot, unsigned long flags);
+int security_mmap_addr(unsigned long addr);
 int security_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
 			   unsigned long prot);
 int security_file_lock(struct file *file, unsigned int cmd);
@@ -2182,11 +2183,14 @@ static inline int security_file_ioctl(struct file *file, unsigned int cmd,
 	return 0;
 }
 
-static inline int security_file_mmap(struct file *file, unsigned long reqprot,
+static inline int security_mmap_file(struct file *file, unsigned long reqprot,
 				     unsigned long prot,
-				     unsigned long flags,
-				     unsigned long addr,
-				     unsigned long addr_only)
+				     unsigned long flags)
+{
+	return 0;
+}
+
+static inline int security_mmap_addr(unsigned long addr)
 {
 	return cap_mmap_addr(addr);
 }
diff --git a/mm/mmap.c b/mm/mmap.c
index 83c56624f1f6..49283da9a2ae 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1101,7 +1101,11 @@ static unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 		}
 	}
 
-	error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
+	error = security_mmap_addr(addr);
+	if (error)
+		return error;
+
+	error = security_mmap_file(file, reqprot, prot, flags);
 	if (error)
 		return error;
 
@@ -1817,7 +1821,7 @@ int expand_downwards(struct vm_area_struct *vma,
 		return -ENOMEM;
 
 	address &= PAGE_MASK;
-	error = security_file_mmap(NULL, 0, 0, 0, address, 1);
+	error = security_mmap_addr(address);
 	if (error)
 		return error;
 
@@ -2205,7 +2209,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len)
 	if (!len)
 		return addr;
 
-	error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
+	error = security_mmap_addr(addr);
 	if (error)
 		return error;
 
@@ -2561,7 +2565,7 @@ int install_special_mapping(struct mm_struct *mm,
 	vma->vm_ops = &special_mapping_vmops;
 	vma->vm_private_data = pages;
 
-	ret = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
+	ret = security_mmap_addr(vma->vm_start);
 	if (ret)
 		goto out;
 
diff --git a/mm/mremap.c b/mm/mremap.c
index 169c53b87749..ebf10892b63d 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -371,7 +371,7 @@ static unsigned long mremap_to(unsigned long addr,
 	if ((addr <= new_addr) && (addr+old_len) > new_addr)
 		goto out;
 
-	ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
+	ret = security_mmap_addr(new_addr);
 	if (ret)
 		goto out;
 
@@ -532,7 +532,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 			goto out;
 		}
 
-		ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
+		ret = security_mmap_addr(new_addr);
 		if (ret)
 			goto out;
 		ret = move_vma(vma, addr, old_len, new_len, new_addr);
diff --git a/mm/nommu.c b/mm/nommu.c
index de6084e3a046..acfe419785db 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1047,7 +1047,10 @@ static int validate_mmap_request(struct file *file,
 	}
 
 	/* allow the security API to have its say */
-	ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
+	ret = security_mmap_addr(addr);
+	if (ret < 0)
+		return ret;
+	ret = security_mmap_file(file, reqprot, prot, flags);
 	if (ret < 0)
 		return ret;
 
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 8430d8937afb..8ea39aabe948 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -490,17 +490,9 @@ static int common_mmap(int op, struct file *file, unsigned long prot,
 	return common_file_perm(op, file, mask);
 }
 
-static int apparmor_file_mmap(struct file *file, unsigned long reqprot,
-			      unsigned long prot, unsigned long flags,
-			      unsigned long addr, unsigned long addr_only)
+static int apparmor_mmap_file(struct file *file, unsigned long reqprot,
+			      unsigned long prot, unsigned long flags)
 {
-	int rc = 0;
-
-	/* do DAC check */
-	rc = cap_mmap_addr(addr);
-	if (rc || addr_only)
-		return rc;
-
 	return common_mmap(OP_FMMAP, file, prot, flags);
 }
 
@@ -646,7 +638,8 @@ static struct security_operations apparmor_ops = {
 	.file_permission =		apparmor_file_permission,
 	.file_alloc_security =		apparmor_file_alloc_security,
 	.file_free_security =		apparmor_file_free_security,
-	.file_mmap =			apparmor_file_mmap,
+	.mmap_file =			apparmor_mmap_file,
+	.mmap_addr =			cap_mmap_addr,
 	.file_mprotect =		apparmor_file_mprotect,
 	.file_lock =			apparmor_file_lock,
 
diff --git a/security/capability.c b/security/capability.c
index fca889676c5e..61095df8b89a 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -949,7 +949,8 @@ void __init security_fixup_ops(struct security_operations *ops)
 	set_to_cap_if_null(ops, file_alloc_security);
 	set_to_cap_if_null(ops, file_free_security);
 	set_to_cap_if_null(ops, file_ioctl);
-	set_to_cap_if_null(ops, file_mmap);
+	set_to_cap_if_null(ops, mmap_addr);
+	set_to_cap_if_null(ops, mmap_file);
 	set_to_cap_if_null(ops, file_mprotect);
 	set_to_cap_if_null(ops, file_lock);
 	set_to_cap_if_null(ops, file_fcntl);
diff --git a/security/commoncap.c b/security/commoncap.c
index ebac3618896e..6dbae4650abe 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -980,23 +980,8 @@ int cap_mmap_addr(unsigned long addr)
 	return ret;
 }
 
-/*
- * 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 cap_mmap_file(struct file *file, unsigned long reqprot,
+		  unsigned long prot, unsigned long flags)
 {
-	return cap_mmap_addr(addr);
+	return 0;
 }
diff --git a/security/security.c b/security/security.c
index 5497a57fba01..d91c66d3956b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -657,18 +657,22 @@ int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	return security_ops->file_ioctl(file, cmd, arg);
 }
 
-int security_file_mmap(struct file *file, unsigned long reqprot,
-			unsigned long prot, unsigned long flags,
-			unsigned long addr, unsigned long addr_only)
+int security_mmap_file(struct file *file, unsigned long reqprot,
+			unsigned long prot, unsigned long flags)
 {
 	int ret;
 
-	ret = security_ops->file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	ret = security_ops->mmap_file(file, reqprot, prot, flags);
 	if (ret)
 		return ret;
 	return ima_file_mmap(file, prot);
 }
 
+int security_mmap_addr(unsigned long addr)
+{
+	return security_ops->mmap_addr(addr);
+}
+
 int security_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
 			    unsigned long prot)
 {
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 25c125eaa3d8..372ec6502aa8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3083,9 +3083,7 @@ error:
 	return rc;
 }
 
-static int selinux_file_mmap(struct file *file, unsigned long reqprot,
-			     unsigned long prot, unsigned long flags,
-			     unsigned long addr, unsigned long addr_only)
+static int selinux_mmap_addr(unsigned long addr)
 {
 	int rc = 0;
 	u32 sid = current_sid();
@@ -3104,10 +3102,12 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
 	}
 
 	/* do DAC check on address space usage */
-	rc = cap_mmap_addr(addr);
-	if (rc || addr_only)
-		return rc;
+	return cap_mmap_addr(addr);
+}
 
+static int selinux_mmap_file(struct file *file, unsigned long reqprot,
+			     unsigned long prot, unsigned long flags)
+{
 	if (selinux_checkreqprot)
 		prot = reqprot;
 
@@ -5570,7 +5570,8 @@ static struct security_operations selinux_ops = {
 	.file_alloc_security =		selinux_file_alloc_security,
 	.file_free_security =		selinux_file_free_security,
 	.file_ioctl =			selinux_file_ioctl,
-	.file_mmap =			selinux_file_mmap,
+	.mmap_file =			selinux_mmap_file,
+	.mmap_addr =			selinux_mmap_addr,
 	.file_mprotect =		selinux_file_mprotect,
 	.file_lock =			selinux_file_lock,
 	.file_fcntl =			selinux_file_fcntl,
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index a62197718768..ee0bb5735f35 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1171,7 +1171,7 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
 }
 
 /**
- * smack_file_mmap :
+ * smack_mmap_file :
  * Check permissions for a mmap operation.  The @file may be NULL, e.g.
  * if mapping anonymous memory.
  * @file contains the file structure for file to map (may be NULL).
@@ -1180,10 +1180,9 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
  * @flags contains the operational flags.
  * Return 0 if permission is granted.
  */
-static int smack_file_mmap(struct file *file,
+static int smack_mmap_file(struct file *file,
 			   unsigned long reqprot, unsigned long prot,
-			   unsigned long flags, unsigned long addr,
-			   unsigned long addr_only)
+			   unsigned long flags)
 {
 	struct smack_known *skp;
 	struct smack_rule *srp;
@@ -1198,11 +1197,6 @@ static int smack_file_mmap(struct file *file,
 	int tmay;
 	int rc;
 
-	/* do DAC check on address space usage */
-	rc = cap_mmap_addr(addr);
-	if (rc || addr_only)
-		return rc;
-
 	if (file == NULL || file->f_dentry == NULL)
 		return 0;
 
@@ -3482,7 +3476,8 @@ struct security_operations smack_ops = {
 	.file_ioctl = 			smack_file_ioctl,
 	.file_lock = 			smack_file_lock,
 	.file_fcntl = 			smack_file_fcntl,
-	.file_mmap =			smack_file_mmap,
+	.mmap_file =			smack_mmap_file,
+	.mmap_addr =			cap_mmap_addr,
 	.file_set_fowner = 		smack_file_set_fowner,
 	.file_send_sigiotask = 		smack_file_send_sigiotask,
 	.file_receive = 		smack_file_receive,
-- 
cgit v1.3-8-gc7d7


From 8b3ec6814c83d76b85bd13badc48552836c24839 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 30 May 2012 17:11:23 -0400
Subject: take security_mmap_file() outside of ->mmap_sem

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 include/linux/security.h |  7 +++----
 ipc/shm.c                |  5 +++++
 mm/mmap.c                | 23 ++++++++++++-----------
 mm/nommu.c               | 22 ++++++++++++----------
 security/security.c      | 33 ++++++++++++++++++++++++++++++---
 5 files changed, 62 insertions(+), 28 deletions(-)

(limited to 'include/linux/security.h')

diff --git a/include/linux/security.h b/include/linux/security.h
index f1bae0963ddc..4e5a73cdbbef 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1745,8 +1745,8 @@ int security_file_permission(struct file *file, int mask);
 int security_file_alloc(struct file *file);
 void security_file_free(struct file *file);
 int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
-int security_mmap_file(struct file *file, unsigned long reqprot,
-			unsigned long prot, unsigned long flags);
+int security_mmap_file(struct file *file, unsigned long prot,
+			unsigned long flags);
 int security_mmap_addr(unsigned long addr);
 int security_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
 			   unsigned long prot);
@@ -2183,8 +2183,7 @@ static inline int security_file_ioctl(struct file *file, unsigned int cmd,
 	return 0;
 }
 
-static inline int security_mmap_file(struct file *file, unsigned long reqprot,
-				     unsigned long prot,
+static inline int security_mmap_file(struct file *file, unsigned long prot,
 				     unsigned long flags)
 {
 	return 0;
diff --git a/ipc/shm.c b/ipc/shm.c
index 406c5b208193..e3a8063b1768 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1036,6 +1036,10 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 	sfd->file = shp->shm_file;
 	sfd->vm_ops = NULL;
 
+	err = security_mmap_file(file, prot, flags);
+	if (err)
+		goto out_fput;
+
 	down_write(&current->mm->mmap_sem);
 	if (addr && !(shmflg & SHM_REMAP)) {
 		err = -EINVAL;
@@ -1058,6 +1062,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 invalid:
 	up_write(&current->mm->mmap_sem);
 
+out_fput:
 	fput(file);
 
 out_nattch:
diff --git a/mm/mmap.c b/mm/mmap.c
index 49283da9a2ae..34b280f4238d 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -979,7 +979,6 @@ static unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 	struct inode *inode;
 	vm_flags_t vm_flags;
 	int error;
-	unsigned long reqprot = prot;
 
 	/*
 	 * Does the application expect PROT_READ to imply PROT_EXEC?
@@ -1105,10 +1104,6 @@ static unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 	if (error)
 		return error;
 
-	error = security_mmap_file(file, reqprot, prot, flags);
-	if (error)
-		return error;
-
 	return mmap_region(file, addr, len, flags, vm_flags, pgoff);
 }
 
@@ -1130,9 +1125,12 @@ unsigned long vm_mmap(struct file *file, unsigned long addr,
 	unsigned long ret;
 	struct mm_struct *mm = current->mm;
 
-	down_write(&mm->mmap_sem);
-	ret = do_mmap(file, addr, len, prot, flag, offset);
-	up_write(&mm->mmap_sem);
+	ret = security_mmap_file(file, prot, flag);
+	if (!ret) {
+		down_write(&mm->mmap_sem);
+		ret = do_mmap(file, addr, len, prot, flag, offset);
+		up_write(&mm->mmap_sem);
+	}
 	return ret;
 }
 EXPORT_SYMBOL(vm_mmap);
@@ -1168,9 +1166,12 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 
 	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 
-	down_write(&current->mm->mmap_sem);
-	retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-	up_write(&current->mm->mmap_sem);
+	retval = security_mmap_file(file, prot, flags);
+	if (!retval) {
+		down_write(&current->mm->mmap_sem);
+		retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+		up_write(&current->mm->mmap_sem);
+	}
 
 	if (file)
 		fput(file);
diff --git a/mm/nommu.c b/mm/nommu.c
index acfe419785db..8cbfd623b04a 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -889,7 +889,6 @@ static int validate_mmap_request(struct file *file,
 				 unsigned long *_capabilities)
 {
 	unsigned long capabilities, rlen;
-	unsigned long reqprot = prot;
 	int ret;
 
 	/* do the simple checks first */
@@ -1048,9 +1047,6 @@ static int validate_mmap_request(struct file *file,
 
 	/* allow the security API to have its say */
 	ret = security_mmap_addr(addr);
-	if (ret < 0)
-		return ret;
-	ret = security_mmap_file(file, reqprot, prot, flags);
 	if (ret < 0)
 		return ret;
 
@@ -1492,9 +1488,12 @@ unsigned long vm_mmap(struct file *file, unsigned long addr,
 	unsigned long ret;
 	struct mm_struct *mm = current->mm;
 
-	down_write(&mm->mmap_sem);
-	ret = do_mmap(file, addr, len, prot, flag, offset);
-	up_write(&mm->mmap_sem);
+	ret = security_mmap_file(file, prot, flag);
+	if (!ret) {
+		down_write(&mm->mmap_sem);
+		ret = do_mmap(file, addr, len, prot, flag, offset);
+		up_write(&mm->mmap_sem);
+	}
 	return ret;
 }
 EXPORT_SYMBOL(vm_mmap);
@@ -1515,9 +1514,12 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 
 	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 
-	down_write(&current->mm->mmap_sem);
-	retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-	up_write(&current->mm->mmap_sem);
+	ret = security_mmap_file(file, prot, flags);
+	if (!ret) {
+		down_write(&current->mm->mmap_sem);
+		retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+		up_write(&current->mm->mmap_sem);
+	}
 
 	if (file)
 		fput(file);
diff --git a/security/security.c b/security/security.c
index d91c66d3956b..3b11b3b72fe2 100644
--- a/security/security.c
+++ b/security/security.c
@@ -20,6 +20,9 @@
 #include <linux/ima.h>
 #include <linux/evm.h>
 #include <linux/fsnotify.h>
+#include <linux/mman.h>
+#include <linux/mount.h>
+#include <linux/personality.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR	2
@@ -657,11 +660,35 @@ int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	return security_ops->file_ioctl(file, cmd, arg);
 }
 
-int security_mmap_file(struct file *file, unsigned long reqprot,
-			unsigned long prot, unsigned long flags)
+int security_mmap_file(struct file *file, unsigned long prot,
+			unsigned long flags)
 {
+	unsigned long reqprot = prot;
 	int ret;
-
+	/*
+	 * Does the application expect PROT_READ to imply PROT_EXEC?
+	 *
+	 * (the exception is when the underlying filesystem is noexec
+	 *  mounted, in which case we dont add PROT_EXEC.)
+	 */
+	if (!(reqprot & PROT_READ))
+		goto out;
+	if (!(current->personality & READ_IMPLIES_EXEC))
+		goto out;
+	if (!file) {
+		prot |= PROT_EXEC;
+	} else if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) {
+#ifndef CONFIG_MMU
+		unsigned long caps = 0;
+		struct address_space *mapping = file->f_mapping;
+		if (mapping && mapping->backing_dev_info)
+			caps = mapping->backing_dev_info->capabilities;
+		if (!(caps & BDI_CAP_EXEC_MAP))
+			goto out;
+#endif
+		prot |= PROT_EXEC;
+	}
+out:
 	ret = security_ops->mmap_file(file, reqprot, prot, flags);
 	if (ret)
 		return ret;
-- 
cgit v1.3-8-gc7d7