aboutsummaryrefslogtreecommitdiffstats
path: root/security/commoncap.c
diff options
context:
space:
mode:
Diffstat (limited to 'security/commoncap.c')
-rw-r--r--security/commoncap.c244
1 files changed, 228 insertions, 16 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index 0f8a2ce3f3a..afca6dd4ae6 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -22,6 +22,7 @@
#include <linux/ptrace.h>
#include <linux/xattr.h>
#include <linux/hugetlb.h>
+#include <linux/mount.h>
int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
{
@@ -108,14 +109,130 @@ void cap_capset_set (struct task_struct *target, kernel_cap_t *effective,
target->cap_permitted = *permitted;
}
+static inline void bprm_clear_caps(struct linux_binprm *bprm)
+{
+ cap_clear(bprm->cap_inheritable);
+ cap_clear(bprm->cap_permitted);
+ bprm->cap_effective = false;
+}
+
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
+
+int cap_inode_need_killpriv(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ int error;
+
+ if (!inode->i_op || !inode->i_op->getxattr)
+ return 0;
+
+ error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
+ if (error <= 0)
+ return 0;
+ return 1;
+}
+
+int cap_inode_killpriv(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ if (!inode->i_op || !inode->i_op->removexattr)
+ return 0;
+
+ return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
+}
+
+static inline int cap_from_disk(__le32 *caps, struct linux_binprm *bprm,
+ int size)
+{
+ __u32 magic_etc;
+
+ if (size != XATTR_CAPS_SZ)
+ return -EINVAL;
+
+ magic_etc = le32_to_cpu(caps[0]);
+
+ 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;
+ default:
+ return -EINVAL;
+ }
+}
+
+/* Locate any VFS capabilities: */
+static int get_file_caps(struct linux_binprm *bprm)
+{
+ struct dentry *dentry;
+ int rc = 0;
+ __le32 v1caps[XATTR_CAPS_SZ];
+ struct inode *inode;
+
+ if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) {
+ bprm_clear_caps(bprm);
+ return 0;
+ }
+
+ dentry = dget(bprm->file->f_dentry);
+ inode = dentry->d_inode;
+ if (!inode->i_op || !inode->i_op->getxattr)
+ goto out;
+
+ rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, &v1caps,
+ XATTR_CAPS_SZ);
+ if (rc == -ENODATA || rc == -EOPNOTSUPP) {
+ /* no data, that's ok */
+ rc = 0;
+ goto out;
+ }
+ if (rc < 0)
+ goto out;
+
+ rc = cap_from_disk(v1caps, bprm, rc);
+ if (rc)
+ printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
+ __FUNCTION__, rc, bprm->filename);
+
+out:
+ dput(dentry);
+ if (rc)
+ bprm_clear_caps(bprm);
+
+ return rc;
+}
+
+#else
+int cap_inode_need_killpriv(struct dentry *dentry)
+{
+ return 0;
+}
+
+int cap_inode_killpriv(struct dentry *dentry)
+{
+ return 0;
+}
+
+static inline int get_file_caps(struct linux_binprm *bprm)
+{
+ bprm_clear_caps(bprm);
+ return 0;
+}
+#endif
+
int cap_bprm_set_security (struct linux_binprm *bprm)
{
- /* Copied from fs/exec.c:prepare_binprm. */
+ int ret;
- /* We don't have VFS support for capabilities yet */
- cap_clear (bprm->cap_inheritable);
- cap_clear (bprm->cap_permitted);
- cap_clear (bprm->cap_effective);
+ ret = get_file_caps(bprm);
+ if (ret)
+ printk(KERN_NOTICE "%s: get_file_caps returned %d for %s\n",
+ __FUNCTION__, ret, bprm->filename);
/* To support inheritance of root-permissions and suid-root
* executables under compatibility mode, we raise all three
@@ -131,9 +248,10 @@ int cap_bprm_set_security (struct linux_binprm *bprm)
cap_set_full (bprm->cap_permitted);
}
if (bprm->e_uid == 0)
- cap_set_full (bprm->cap_effective);
+ bprm->cap_effective = true;
}
- return 0;
+
+ return ret;
}
void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
@@ -149,6 +267,7 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
!cap_issubset (new_permitted, current->cap_permitted)) {
set_dumpable(current->mm, suid_dumpable);
+ current->pdeath_signal = 0;
if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
if (!capable(CAP_SETUID)) {
@@ -170,8 +289,8 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
* capability rules */
if (!is_init(current)) {
current->cap_permitted = new_permitted;
- current->cap_effective =
- cap_intersect (new_permitted, bprm->cap_effective);
+ current->cap_effective = bprm->cap_effective ?
+ new_permitted : 0;
}
/* AUD: Audit candidate if current->cap_effective is set */
@@ -181,11 +300,15 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
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. */
+ if (current->uid != 0) {
+ if (bprm->cap_effective)
+ return 1;
+ if (!cap_isclear(bprm->cap_permitted))
+ return 1;
+ if (!cap_isclear(bprm->cap_inheritable))
+ return 1;
+ }
+
return (current->euid != current->uid ||
current->egid != current->gid);
}
@@ -193,7 +316,11 @@ int cap_bprm_secureexec (struct linux_binprm *bprm)
int cap_inode_setxattr(struct dentry *dentry, char *name, void *value,
size_t size, int flags)
{
- if (!strncmp(name, XATTR_SECURITY_PREFIX,
+ if (!strcmp(name, XATTR_NAME_CAPS)) {
+ if (!capable(CAP_SETFCAP))
+ return -EPERM;
+ return 0;
+ } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
sizeof(XATTR_SECURITY_PREFIX) - 1) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -202,7 +329,11 @@ int cap_inode_setxattr(struct dentry *dentry, char *name, void *value,
int cap_inode_removexattr(struct dentry *dentry, char *name)
{
- if (!strncmp(name, XATTR_SECURITY_PREFIX,
+ if (!strcmp(name, XATTR_NAME_CAPS)) {
+ if (!capable(CAP_SETFCAP))
+ return -EPERM;
+ return 0;
+ } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
sizeof(XATTR_SECURITY_PREFIX) - 1) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -299,6 +430,83 @@ int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
return 0;
}
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
+/*
+ * Rationale: code calling task_setscheduler, task_setioprio, and
+ * task_setnice, assumes that
+ * . if capable(cap_sys_nice), then those actions should be allowed
+ * . if not capable(cap_sys_nice), but acting on your own processes,
+ * then those actions should be allowed
+ * This is insufficient now since you can call code without suid, but
+ * yet with increased caps.
+ * So we check for increased caps on the target process.
+ */
+static inline int cap_safe_nice(struct task_struct *p)
+{
+ if (!cap_issubset(p->cap_permitted, current->cap_permitted) &&
+ !__capable(current, CAP_SYS_NICE))
+ return -EPERM;
+ return 0;
+}
+
+int cap_task_setscheduler (struct task_struct *p, int policy,
+ struct sched_param *lp)
+{
+ return cap_safe_nice(p);
+}
+
+int cap_task_setioprio (struct task_struct *p, int ioprio)
+{
+ return cap_safe_nice(p);
+}
+
+int cap_task_setnice (struct task_struct *p, int nice)
+{
+ return cap_safe_nice(p);
+}
+
+int cap_task_kill(struct task_struct *p, struct siginfo *info,
+ int sig, u32 secid)
+{
+ if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
+ return 0;
+
+ if (secid)
+ /*
+ * Signal sent as a particular user.
+ * Capabilities are ignored. May be wrong, but it's the
+ * only thing we can do at the moment.
+ * Used only by usb drivers?
+ */
+ return 0;
+ if (cap_issubset(p->cap_permitted, current->cap_permitted))
+ return 0;
+ if (capable(CAP_KILL))
+ return 0;
+
+ return -EPERM;
+}
+#else
+int cap_task_setscheduler (struct task_struct *p, int policy,
+ struct sched_param *lp)
+{
+ return 0;
+}
+int cap_task_setioprio (struct task_struct *p, int ioprio)
+{
+ return 0;
+}
+int cap_task_setnice (struct task_struct *p, int nice)
+{
+ return 0;
+}
+int cap_task_kill(struct task_struct *p, struct siginfo *info,
+ int sig, u32 secid)
+{
+ return 0;
+}
+#endif
+
void cap_task_reparent_to_init (struct task_struct *p)
{
p->cap_effective = CAP_INIT_EFF_SET;
@@ -336,6 +544,10 @@ 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_kill);
+EXPORT_SYMBOL(cap_task_setscheduler);
+EXPORT_SYMBOL(cap_task_setioprio);
+EXPORT_SYMBOL(cap_task_setnice);
EXPORT_SYMBOL(cap_task_reparent_to_init);
EXPORT_SYMBOL(cap_syslog);
EXPORT_SYMBOL(cap_vm_enough_memory);