1 files changed, 82 insertions, 52 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index ea61bc73f6d3..5aba82679a0b 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -1,4 +1,4 @@
-/* Common capabilities, needed by capability.o and root_plug.o 
+/* 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
@@ -25,20 +25,6 @@
 #include <linux/mount.h>
 #include <linux/sched.h>
 
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
-/*
- * Because of the reduced scope of CAP_SETPCAP when filesystem
- * capabilities are in effect, it is safe to allow this capability to
- * be available in the default configuration.
- */
-# define CAP_INIT_BSET  CAP_FULL_SET
-#else /* ie. ndef CONFIG_SECURITY_FILE_CAPABILITIES */
-# define CAP_INIT_BSET  CAP_INIT_EFF_SET
-#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
-
-kernel_cap_t cap_bset = CAP_INIT_BSET;    /* systemwide capability bound */
-EXPORT_SYMBOL(cap_bset);
-
 /* Global security state */
 
 unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
@@ -93,9 +79,9 @@ 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);
+        *effective = target->cap_effective;
+        *inheritable = target->cap_inheritable;
+        *permitted = target->cap_permitted;
         return 0;
 }
 
@@ -140,6 +126,12 @@ int cap_capset_check (struct task_struct *target, kernel_cap_t *effective,
                 /* incapable of using this inheritable set */
                 return -EPERM;
         }
+        if (!cap_issubset(*inheritable,
+                           cap_combine(target->cap_inheritable,
+                                       current->cap_bset))) {
+                /* no new pI capabilities outside bounding set */
+                return -EPERM;
+        }
 
         /* verify restrictions on target's new Permitted set */
         if (!cap_issubset (*permitted,
@@ -198,28 +190,50 @@ int cap_inode_killpriv(struct dentry *dentry)
 }
 
 static inline int cap_from_disk(struct vfs_cap_data *caps,
-                                struct linux_binprm *bprm,
-                                int size)
+                                struct linux_binprm *bprm, unsigned size)
 {
         __u32 magic_etc;
+        unsigned tocopy, i;
 
-        if (size != XATTR_CAPS_SZ)
+        if (size < sizeof(magic_etc))
                 return -EINVAL;
 
         magic_etc = le32_to_cpu(caps->magic_etc);
 
         switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
-        case VFS_CAP_REVISION:
-                if (magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
-                        bprm->cap_effective = true;
-                else
-                        bprm->cap_effective = false;
-                bprm->cap_permitted = to_cap_t(le32_to_cpu(caps->permitted));
-                bprm->cap_inheritable = to_cap_t(le32_to_cpu(caps->inheritable));
-                return 0;
+        case VFS_CAP_REVISION_1:
+                if (size != XATTR_CAPS_SZ_1)
+                        return -EINVAL;
+                tocopy = VFS_CAP_U32_1;
+                break;
+        case VFS_CAP_REVISION_2:
+                if (size != XATTR_CAPS_SZ_2)
+                        return -EINVAL;
+                tocopy = VFS_CAP_U32_2;
+                break;
         default:
                 return -EINVAL;
         }
+
+        if (magic_etc & VFS_CAP_FLAGS_EFFECTIVE) {
+                bprm->cap_effective = true;
+        } else {
+                bprm->cap_effective = false;
+        }
+
+        for (i = 0; i < tocopy; ++i) {
+                bprm->cap_permitted.cap[i] =
+                        le32_to_cpu(caps->data[i].permitted);
+                bprm->cap_inheritable.cap[i] =
+                        le32_to_cpu(caps->data[i].inheritable);
+        }
+        while (i < VFS_CAP_U32) {
+                bprm->cap_permitted.cap[i] = 0;
+                bprm->cap_inheritable.cap[i] = 0;
+                i++;
+        }
+
+        return 0;
 }
 
 /* Locate any VFS capabilities: */
@@ -227,7 +241,7 @@ static int get_file_caps(struct linux_binprm *bprm)
 {
         struct dentry *dentry;
         int rc = 0;
-        struct vfs_cap_data incaps;
+        struct vfs_cap_data vcaps;
         struct inode *inode;
 
         if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) {
@@ -240,14 +254,8 @@ static int get_file_caps(struct linux_binprm *bprm)
         if (!inode->i_op || !inode->i_op->getxattr)
                 goto out;
 
-        rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
-        if (rc > 0) {
-                if (rc == XATTR_CAPS_SZ)
-                        rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS,
-                                                &incaps, XATTR_CAPS_SZ);
-                else
-                        rc = -EINVAL;
-        }
+        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;
@@ -256,7 +264,7 @@ static int get_file_caps(struct linux_binprm *bprm)
         if (rc < 0)
                 goto out;
 
-        rc = cap_from_disk(&incaps, bprm, rc);
+        rc = cap_from_disk(&vcaps, bprm, rc);
         if (rc)
                 printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
                         __FUNCTION__, rc, bprm->filename);
@@ -321,10 +329,11 @@ 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,
+        new_permitted = cap_intersect(bprm->cap_permitted,
+                                 current->cap_bset);
+        working = cap_intersect(bprm->cap_inheritable,
                                  current->cap_inheritable);
-        new_permitted = cap_combine (new_permitted, working);
+        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)) {
@@ -351,8 +360,10 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
          * capability rules */
         if (!is_global_init(current)) {
                 current->cap_permitted = new_permitted;
-                current->cap_effective = bprm->cap_effective ?
-                                new_permitted : 0;
+                if (bprm->cap_effective)
+                        current->cap_effective = new_permitted;
+                else
+                        cap_clear(current->cap_effective);
         }
 
         /* AUD: Audit candidate if current->cap_effective is set */
@@ -474,13 +485,15 @@ int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
 
                         if (!issecure (SECURE_NO_SETUID_FIXUP)) {
                                 if (old_fsuid == 0 && current->fsuid != 0) {
-                                        cap_t (current->cap_effective) &=
-                                            ~CAP_FS_MASK;
+                                        current->cap_effective =
+                                                cap_drop_fs_set(
+                                                    current->cap_effective);
                                 }
                                 if (old_fsuid != 0 && current->fsuid == 0) {
-                                        cap_t (current->cap_effective) |=
-                                            (cap_t (current->cap_permitted) &
-                                             CAP_FS_MASK);
+                                        current->cap_effective =
+                                                cap_raise_fs_set(
+                                                    current->cap_effective,
+                                                    current->cap_permitted);
                                 }
                         }
                         break;
@@ -561,6 +574,23 @@ int cap_task_kill(struct task_struct *p, struct siginfo *info,
 
         return -EPERM;
 }
+
+/*
+ * 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.
+ */
+long cap_prctl_drop(unsigned long cap)
+{
+        if (!capable(CAP_SETPCAP))
+                return -EPERM;
+        if (!cap_valid(cap))
+                return -EINVAL;
+        cap_lower(current->cap_bset, cap);
+        return 0;
+}
 #else
 int cap_task_setscheduler (struct task_struct *p, int policy,
                            struct sched_param *lp)
@@ -584,9 +614,9 @@ int cap_task_kill(struct task_struct *p, struct siginfo *info,
 
 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;
+        cap_set_init_eff(p->cap_effective);
+        cap_clear(p->cap_inheritable);
+        cap_set_full(p->cap_permitted);
         p->keep_capabilities = 0;
         return;
 }