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authorAndrew Morgan <morgan@kernel.org>2008-02-04 22:29:42 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 09:44:20 -0800
commite338d263a76af78fe8f38a72131188b58fceb591 (patch)
treef3f046fc6fd66de43de7191830f0daf3bc4ec8eb /security
parent8f6936f4d29aa14e54a2470b954a2e1f96322988 (diff)
downloadlinux-linaro-e338d263a76af78fe8f38a72131188b58fceb591.tar.gz
Add 64-bit capability support to the kernel
The patch supports legacy (32-bit) capability userspace, and where possible translates 32-bit capabilities to/from userspace and the VFS to 64-bit kernel space capabilities. If a capability set cannot be compressed into 32-bits for consumption by user space, the system call fails, with -ERANGE. FWIW libcap-2.00 supports this change (and earlier capability formats) http://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/ [akpm@linux-foundation.org: coding-syle fixes] [akpm@linux-foundation.org: use get_task_comm()] [ezk@cs.sunysb.edu: build fix] [akpm@linux-foundation.org: do not initialise statics to 0 or NULL] [akpm@linux-foundation.org: unused var] [serue@us.ibm.com: export __cap_ symbols] Signed-off-by: Andrew G. Morgan <morgan@kernel.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security')
-rw-r--r--security/commoncap.c87
-rw-r--r--security/dummy.c17
2 files changed, 68 insertions, 36 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index b06617b35b9..01ab47845dc 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
@@ -93,9 +93,9 @@ 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;
}
@@ -197,28 +197,51 @@ int cap_inode_killpriv(struct dentry *dentry)
return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
}
-static inline int cap_from_disk(__le32 *caps, struct linux_binprm *bprm,
- int size)
+static inline int cap_from_disk(struct vfs_cap_data *caps,
+ 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[0]);
+ 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[1]));
- bprm->cap_inheritable = to_cap_t(le32_to_cpu(caps[2]));
- 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: */
@@ -226,7 +249,7 @@ static int get_file_caps(struct linux_binprm *bprm)
{
struct dentry *dentry;
int rc = 0;
- __le32 v1caps[XATTR_CAPS_SZ];
+ struct vfs_cap_data vcaps;
struct inode *inode;
if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) {
@@ -239,8 +262,8 @@ 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, &v1caps,
- XATTR_CAPS_SZ);
+ 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;
@@ -249,7 +272,7 @@ static int get_file_caps(struct linux_binprm *bprm)
if (rc < 0)
goto out;
- rc = cap_from_disk(v1caps, 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);
@@ -344,8 +367,10 @@ 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 */
@@ -467,13 +492,15 @@ 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;
@@ -577,9 +604,9 @@ 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;
}
diff --git a/security/dummy.c b/security/dummy.c
index c505122e22d..649326bf64e 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -36,14 +36,19 @@ static int dummy_ptrace (struct task_struct *parent, struct task_struct *child)
static int dummy_capget (struct task_struct *target, kernel_cap_t * effective,
kernel_cap_t * inheritable, kernel_cap_t * permitted)
{
- *effective = *inheritable = *permitted = 0;
if (target->euid == 0) {
- *permitted |= (~0 & ~CAP_FS_MASK);
- *effective |= (~0 & ~CAP_TO_MASK(CAP_SETPCAP) & ~CAP_FS_MASK);
+ cap_set_full(*permitted);
+ cap_set_init_eff(*effective);
+ } else {
+ cap_clear(*permitted);
+ cap_clear(*effective);
}
- if (target->fsuid == 0) {
- *permitted |= CAP_FS_MASK;
- *effective |= CAP_FS_MASK;
+
+ cap_clear(*inheritable);
+
+ if (target->fsuid != 0) {
+ *permitted = cap_drop_fs_set(*permitted);
+ *effective = cap_drop_fs_set(*effective);
}
return 0;
}