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-rw-r--r--kernel/capability.c338
1 files changed, 221 insertions, 117 deletions
diff --git a/kernel/capability.c b/kernel/capability.c
index 901e0fdc3ff..0101e847603 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -115,11 +115,208 @@ static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
return 0;
}
+#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
+
+/*
+ * Without filesystem capability support, we nominally support one process
+ * setting the capabilities of another
+ */
+static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
+ kernel_cap_t *pIp, kernel_cap_t *pPp)
+{
+ struct task_struct *target;
+ int ret;
+
+ spin_lock(&task_capability_lock);
+ read_lock(&tasklist_lock);
+
+ if (pid && pid != task_pid_vnr(current)) {
+ target = find_task_by_vpid(pid);
+ if (!target) {
+ ret = -ESRCH;
+ goto out;
+ }
+ } else
+ target = current;
+
+ ret = security_capget(target, pEp, pIp, pPp);
+
+out:
+ read_unlock(&tasklist_lock);
+ spin_unlock(&task_capability_lock);
+
+ return ret;
+}
+
+/*
+ * cap_set_pg - set capabilities for all processes in a given process
+ * group. We call this holding task_capability_lock and tasklist_lock.
+ */
+static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
+ kernel_cap_t *inheritable,
+ kernel_cap_t *permitted)
+{
+ struct task_struct *g, *target;
+ int ret = -EPERM;
+ int found = 0;
+ struct pid *pgrp;
+
+ spin_lock(&task_capability_lock);
+ read_lock(&tasklist_lock);
+
+ pgrp = find_vpid(pgrp_nr);
+ do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
+ target = g;
+ while_each_thread(g, target) {
+ if (!security_capset_check(target, effective,
+ inheritable, permitted)) {
+ security_capset_set(target, effective,
+ inheritable, permitted);
+ ret = 0;
+ }
+ found = 1;
+ }
+ } while_each_pid_task(pgrp, PIDTYPE_PGID, g);
+
+ read_unlock(&tasklist_lock);
+ spin_unlock(&task_capability_lock);
+
+ if (!found)
+ ret = 0;
+ return ret;
+}
+
/*
- * For sys_getproccap() and sys_setproccap(), any of the three
- * capability set pointers may be NULL -- indicating that that set is
- * uninteresting and/or not to be changed.
+ * cap_set_all - set capabilities for all processes other than init
+ * and self. We call this holding task_capability_lock and tasklist_lock.
*/
+static inline int cap_set_all(kernel_cap_t *effective,
+ kernel_cap_t *inheritable,
+ kernel_cap_t *permitted)
+{
+ struct task_struct *g, *target;
+ int ret = -EPERM;
+ int found = 0;
+
+ spin_lock(&task_capability_lock);
+ read_lock(&tasklist_lock);
+
+ do_each_thread(g, target) {
+ if (target == current
+ || is_container_init(target->group_leader))
+ continue;
+ found = 1;
+ if (security_capset_check(target, effective, inheritable,
+ permitted))
+ continue;
+ ret = 0;
+ security_capset_set(target, effective, inheritable, permitted);
+ } while_each_thread(g, target);
+
+ read_unlock(&tasklist_lock);
+ spin_unlock(&task_capability_lock);
+
+ if (!found)
+ ret = 0;
+
+ return ret;
+}
+
+/*
+ * Given the target pid does not refer to the current process we
+ * need more elaborate support... (This support is not present when
+ * filesystem capabilities are configured.)
+ */
+static inline int do_sys_capset_other_tasks(pid_t pid, kernel_cap_t *effective,
+ kernel_cap_t *inheritable,
+ kernel_cap_t *permitted)
+{
+ struct task_struct *target;
+ int ret;
+
+ if (!capable(CAP_SETPCAP))
+ return -EPERM;
+
+ if (pid == -1) /* all procs other than current and init */
+ return cap_set_all(effective, inheritable, permitted);
+
+ else if (pid < 0) /* all procs in process group */
+ return cap_set_pg(-pid, effective, inheritable, permitted);
+
+ /* target != current */
+ spin_lock(&task_capability_lock);
+ read_lock(&tasklist_lock);
+
+ target = find_task_by_vpid(pid);
+ if (!target)
+ ret = -ESRCH;
+ else {
+ ret = security_capset_check(target, effective, inheritable,
+ permitted);
+
+ /* having verified that the proposed changes are legal,
+ we now put them into effect. */
+ if (!ret)
+ security_capset_set(target, effective, inheritable,
+ permitted);
+ }
+
+ read_unlock(&tasklist_lock);
+ spin_unlock(&task_capability_lock);
+
+ return ret;
+}
+
+#else /* ie., def CONFIG_SECURITY_FILE_CAPABILITIES */
+
+/*
+ * If we have configured with filesystem capability support, then the
+ * only thing that can change the capabilities of the current process
+ * is the current process. As such, we can't be in this code at the
+ * same time as we are in the process of setting capabilities in this
+ * process. The net result is that we can limit our use of locks to
+ * when we are reading the caps of another process.
+ */
+static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
+ kernel_cap_t *pIp, kernel_cap_t *pPp)
+{
+ int ret;
+
+ if (pid && (pid != task_pid_vnr(current))) {
+ struct task_struct *target;
+
+ spin_lock(&task_capability_lock);
+ read_lock(&tasklist_lock);
+
+ target = find_task_by_vpid(pid);
+ if (!target)
+ ret = -ESRCH;
+ else
+ ret = security_capget(target, pEp, pIp, pPp);
+
+ read_unlock(&tasklist_lock);
+ spin_unlock(&task_capability_lock);
+ } else
+ ret = security_capget(current, pEp, pIp, pPp);
+
+ return ret;
+}
+
+/*
+ * With filesystem capability support configured, the kernel does not
+ * permit the changing of capabilities in one process by another
+ * process. (CAP_SETPCAP has much less broad semantics when configured
+ * this way.)
+ */
+static inline int do_sys_capset_other_tasks(pid_t pid,
+ kernel_cap_t *effective,
+ kernel_cap_t *inheritable,
+ kernel_cap_t *permitted)
+{
+ return -EPERM;
+}
+
+#endif /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
/*
* Atomically modify the effective capabilities returning the original
@@ -155,7 +352,6 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
{
int ret = 0;
pid_t pid;
- struct task_struct *target;
unsigned tocopy;
kernel_cap_t pE, pI, pP;
@@ -169,23 +365,7 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
if (pid < 0)
return -EINVAL;
- spin_lock(&task_capability_lock);
- read_lock(&tasklist_lock);
-
- if (pid && pid != task_pid_vnr(current)) {
- target = find_task_by_vpid(pid);
- if (!target) {
- ret = -ESRCH;
- goto out;
- }
- } else
- target = current;
-
- ret = security_capget(target, &pE, &pI, &pP);
-
-out:
- read_unlock(&tasklist_lock);
- spin_unlock(&task_capability_lock);
+ ret = cap_get_target_pid(pid, &pE, &pI, &pP);
if (!ret) {
struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
@@ -216,7 +396,6 @@ out:
* before modification is attempted and the application
* fails.
*/
-
if (copy_to_user(dataptr, kdata, tocopy
* sizeof(struct __user_cap_data_struct))) {
return -EFAULT;
@@ -226,70 +405,8 @@ out:
return ret;
}
-/*
- * cap_set_pg - set capabilities for all processes in a given process
- * group. We call this holding task_capability_lock and tasklist_lock.
- */
-static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
- kernel_cap_t *inheritable,
- kernel_cap_t *permitted)
-{
- struct task_struct *g, *target;
- int ret = -EPERM;
- int found = 0;
- struct pid *pgrp;
-
- pgrp = find_vpid(pgrp_nr);
- do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
- target = g;
- while_each_thread(g, target) {
- if (!security_capset_check(target, effective,
- inheritable,
- permitted)) {
- security_capset_set(target, effective,
- inheritable,
- permitted);
- ret = 0;
- }
- found = 1;
- }
- } while_each_pid_task(pgrp, PIDTYPE_PGID, g);
-
- if (!found)
- ret = 0;
- return ret;
-}
-
-/*
- * cap_set_all - set capabilities for all processes other than init
- * and self. We call this holding task_capability_lock and tasklist_lock.
- */
-static inline int cap_set_all(kernel_cap_t *effective,
- kernel_cap_t *inheritable,
- kernel_cap_t *permitted)
-{
- struct task_struct *g, *target;
- int ret = -EPERM;
- int found = 0;
-
- do_each_thread(g, target) {
- if (target == current || is_container_init(target->group_leader))
- continue;
- found = 1;
- if (security_capset_check(target, effective, inheritable,
- permitted))
- continue;
- ret = 0;
- security_capset_set(target, effective, inheritable, permitted);
- } while_each_thread(g, target);
-
- if (!found)
- ret = 0;
- return ret;
-}
-
/**
- * sys_capset - set capabilities for a process or a group of processes
+ * sys_capset - set capabilities for a process or (*) a group of processes
* @header: pointer to struct that contains capability version and
* target pid data
* @data: pointer to struct that contains the effective, permitted,
@@ -313,7 +430,6 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
unsigned i, tocopy;
kernel_cap_t inheritable, permitted, effective;
- struct task_struct *target;
int ret;
pid_t pid;
@@ -324,9 +440,6 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
if (get_user(pid, &header->pid))
return -EFAULT;
- if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
- return -EPERM;
-
if (copy_from_user(&kdata, data, tocopy
* sizeof(struct __user_cap_data_struct))) {
return -EFAULT;
@@ -344,40 +457,31 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
i++;
}
- spin_lock(&task_capability_lock);
- read_lock(&tasklist_lock);
-
- if (pid > 0 && pid != task_pid_vnr(current)) {
- target = find_task_by_vpid(pid);
- if (!target) {
- ret = -ESRCH;
- goto out;
- }
- } else
- target = current;
-
- ret = 0;
-
- /* having verified that the proposed changes are legal,
- we now put them into effect. */
- if (pid < 0) {
- if (pid == -1) /* all procs other than current and init */
- ret = cap_set_all(&effective, &inheritable, &permitted);
+ if (pid && (pid != task_pid_vnr(current)))
+ ret = do_sys_capset_other_tasks(pid, &effective, &inheritable,
+ &permitted);
+ else {
+ /*
+ * This lock is required even when filesystem
+ * capability support is configured - it protects the
+ * sys_capget() call from returning incorrect data in
+ * the case that the targeted process is not the
+ * current one.
+ */
+ spin_lock(&task_capability_lock);
- else /* all procs in process group */
- ret = cap_set_pg(-pid, &effective, &inheritable,
- &permitted);
- } else {
- ret = security_capset_check(target, &effective, &inheritable,
+ ret = security_capset_check(current, &effective, &inheritable,
&permitted);
+ /*
+ * Having verified that the proposed changes are
+ * legal, we now put them into effect.
+ */
if (!ret)
- security_capset_set(target, &effective, &inheritable,
+ security_capset_set(current, &effective, &inheritable,
&permitted);
+ spin_unlock(&task_capability_lock);
}
-out:
- read_unlock(&tasklist_lock);
- spin_unlock(&task_capability_lock);
return ret;
}