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-rw-r--r--security/commoncap.c134
1 files changed, 82 insertions, 52 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index ea61bc73f6d..5aba82679a0 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;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-06 20:41:08 +0000