CRED: Separate task security context from task_struct
Separate the task security context from task_struct. At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.
Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.
With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/include/linux/cred.h b/include/linux/cred.h
index b69222c..3e65587 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -12,39 +12,150 @@
#ifndef _LINUX_CRED_H
#define _LINUX_CRED_H
-#define get_current_user() (get_uid(current->user))
+#include <linux/capability.h>
+#include <linux/key.h>
+#include <asm/atomic.h>
-#define task_uid(task) ((task)->uid)
-#define task_gid(task) ((task)->gid)
-#define task_euid(task) ((task)->euid)
-#define task_egid(task) ((task)->egid)
+struct user_struct;
+struct cred;
-#define current_uid() (current->uid)
-#define current_gid() (current->gid)
-#define current_euid() (current->euid)
-#define current_egid() (current->egid)
-#define current_suid() (current->suid)
-#define current_sgid() (current->sgid)
-#define current_fsuid() (current->fsuid)
-#define current_fsgid() (current->fsgid)
-#define current_cap() (current->cap_effective)
+/*
+ * COW Supplementary groups list
+ */
+#define NGROUPS_SMALL 32
+#define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(gid_t)))
+
+struct group_info {
+ atomic_t usage;
+ int ngroups;
+ int nblocks;
+ gid_t small_block[NGROUPS_SMALL];
+ gid_t *blocks[0];
+};
+
+/**
+ * get_group_info - Get a reference to a group info structure
+ * @group_info: The group info to reference
+ *
+ * This must be called with the owning task locked (via task_lock()) when task
+ * != current. The reason being that the vast majority of callers are looking
+ * at current->group_info, which can not be changed except by the current task.
+ * Changing current->group_info requires the task lock, too.
+ */
+#define get_group_info(group_info) \
+do { \
+ atomic_inc(&(group_info)->usage); \
+} while (0)
+
+/**
+ * put_group_info - Release a reference to a group info structure
+ * @group_info: The group info to release
+ */
+#define put_group_info(group_info) \
+do { \
+ if (atomic_dec_and_test(&(group_info)->usage)) \
+ groups_free(group_info); \
+} while (0)
+
+extern struct group_info *groups_alloc(int);
+extern void groups_free(struct group_info *);
+extern int set_current_groups(struct group_info *);
+extern int set_groups(struct cred *, struct group_info *);
+extern int groups_search(struct group_info *, gid_t);
+
+/* access the groups "array" with this macro */
+#define GROUP_AT(gi, i) \
+ ((gi)->blocks[(i) / NGROUPS_PER_BLOCK][(i) % NGROUPS_PER_BLOCK])
+
+extern int in_group_p(gid_t);
+extern int in_egroup_p(gid_t);
+
+/*
+ * The security context of a task
+ *
+ * The parts of the context break down into two categories:
+ *
+ * (1) The objective context of a task. These parts are used when some other
+ * task is attempting to affect this one.
+ *
+ * (2) The subjective context. These details are used when the task is acting
+ * upon another object, be that a file, a task, a key or whatever.
+ *
+ * Note that some members of this structure belong to both categories - the
+ * LSM security pointer for instance.
+ *
+ * A task has two security pointers. task->real_cred points to the objective
+ * context that defines that task's actual details. The objective part of this
+ * context is used whenever that task is acted upon.
+ *
+ * task->cred points to the subjective context that defines the details of how
+ * that task is going to act upon another object. This may be overridden
+ * temporarily to point to another security context, but normally points to the
+ * same context as task->real_cred.
+ */
+struct cred {
+ atomic_t usage;
+ uid_t uid; /* real UID of the task */
+ gid_t gid; /* real GID of the task */
+ uid_t suid; /* saved UID of the task */
+ gid_t sgid; /* saved GID of the task */
+ uid_t euid; /* effective UID of the task */
+ gid_t egid; /* effective GID of the task */
+ uid_t fsuid; /* UID for VFS ops */
+ gid_t fsgid; /* GID for VFS ops */
+ unsigned securebits; /* SUID-less security management */
+ kernel_cap_t cap_inheritable; /* caps our children can inherit */
+ kernel_cap_t cap_permitted; /* caps we're permitted */
+ kernel_cap_t cap_effective; /* caps we can actually use */
+ kernel_cap_t cap_bset; /* capability bounding set */
+#ifdef CONFIG_KEYS
+ unsigned char jit_keyring; /* default keyring to attach requested
+ * keys to */
+ struct key *thread_keyring; /* keyring private to this thread */
+ struct key *request_key_auth; /* assumed request_key authority */
+#endif
+#ifdef CONFIG_SECURITY
+ void *security; /* subjective LSM security */
+#endif
+ struct user_struct *user; /* real user ID subscription */
+ struct group_info *group_info; /* supplementary groups for euid/fsgid */
+ struct rcu_head rcu; /* RCU deletion hook */
+ spinlock_t lock; /* lock for pointer changes */
+};
+
+#define get_current_user() (get_uid(current->cred->user))
+
+#define task_uid(task) ((task)->cred->uid)
+#define task_gid(task) ((task)->cred->gid)
+#define task_euid(task) ((task)->cred->euid)
+#define task_egid(task) ((task)->cred->egid)
+
+#define current_uid() (current->cred->uid)
+#define current_gid() (current->cred->gid)
+#define current_euid() (current->cred->euid)
+#define current_egid() (current->cred->egid)
+#define current_suid() (current->cred->suid)
+#define current_sgid() (current->cred->sgid)
+#define current_fsuid() (current->cred->fsuid)
+#define current_fsgid() (current->cred->fsgid)
+#define current_cap() (current->cred->cap_effective)
#define current_uid_gid(_uid, _gid) \
do { \
- *(_uid) = current->uid; \
- *(_gid) = current->gid; \
+ *(_uid) = current->cred->uid; \
+ *(_gid) = current->cred->gid; \
} while(0)
#define current_euid_egid(_uid, _gid) \
do { \
- *(_uid) = current->euid; \
- *(_gid) = current->egid; \
+ *(_uid) = current->cred->euid; \
+ *(_gid) = current->cred->egid; \
} while(0)
#define current_fsuid_fsgid(_uid, _gid) \
do { \
- *(_uid) = current->fsuid; \
- *(_gid) = current->fsgid; \
+ *(_uid) = current->cred->fsuid; \
+ *(_gid) = current->cred->fsgid; \
} while(0)
#endif /* _LINUX_CRED_H */