FROMGIT: binder: create node flag to request sender's security context
To allow servers to verify client identity, allow a node
flag to be set that causes the sender's security context
to be delivered with the transaction. The BR_TRANSACTION
command is extended in BR_TRANSACTION_SEC_CTX to
contain a pointer to the security context string.
Signed-off-by: Todd Kjos <tkjos@google.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit ec74136ded792deed80780a2f8baf3521eeb72f9
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
master)
Change-Id: I44496546e2d0dc0022f818a45cd52feb1c1a92cb
Signed-off-by: Todd Kjos <tkjos@google.com>
diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c
index 6b5543b..311960d 100644
--- a/drivers/staging/android/binder.c
+++ b/drivers/staging/android/binder.c
@@ -356,6 +356,7 @@
* @min_priority: minimum scheduling priority
* (invariant after initialized)
* @inherit_rt: inherit RT scheduling policy from caller
+ * @txn_security_ctx: require sender's security context
* (invariant after initialized)
* @async_todo: list of async work items
* (protected by @proc->inner_lock)
@@ -395,6 +396,7 @@
u8 sched_policy:2;
u8 inherit_rt:1;
u8 accept_fds:1;
+ u8 txn_security_ctx:1;
u8 min_priority;
};
bool has_async_transaction;
@@ -652,6 +654,7 @@
struct binder_priority saved_priority;
bool set_priority_called;
kuid_t sender_euid;
+ binder_uintptr_t security_ctx;
/**
* @lock: protects @from, @to_proc, and @to_thread
*
@@ -1316,6 +1319,7 @@
node->min_priority = to_kernel_prio(node->sched_policy, priority);
node->accept_fds = !!(flags & FLAT_BINDER_FLAG_ACCEPTS_FDS);
node->inherit_rt = !!(flags & FLAT_BINDER_FLAG_INHERIT_RT);
+ node->txn_security_ctx = !!(flags & FLAT_BINDER_FLAG_TXN_SECURITY_CTX);
spin_lock_init(&node->lock);
INIT_LIST_HEAD(&node->work.entry);
INIT_LIST_HEAD(&node->async_todo);
@@ -2776,6 +2780,8 @@
binder_size_t last_fixup_min_off = 0;
struct binder_context *context = proc->context;
int t_debug_id = atomic_inc_return(&binder_last_id);
+ char *secctx = NULL;
+ u32 secctx_sz = 0;
e = binder_transaction_log_add(&binder_transaction_log);
e->debug_id = t_debug_id;
@@ -2999,6 +3005,20 @@
t->priority = target_proc->default_priority;
}
+ if (target_node && target_node->txn_security_ctx) {
+ u32 secid;
+
+ security_task_getsecid(proc->tsk, &secid);
+ ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
+ if (ret) {
+ return_error = BR_FAILED_REPLY;
+ return_error_param = ret;
+ return_error_line = __LINE__;
+ goto err_get_secctx_failed;
+ }
+ extra_buffers_size += ALIGN(secctx_sz, sizeof(u64));
+ }
+
trace_binder_transaction(reply, t, target_node);
t->buffer = binder_alloc_new_buf(&target_proc->alloc, tr->data_size,
@@ -3015,6 +3035,19 @@
t->buffer = NULL;
goto err_binder_alloc_buf_failed;
}
+ if (secctx) {
+ size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) +
+ ALIGN(tr->offsets_size, sizeof(void *)) +
+ ALIGN(extra_buffers_size, sizeof(void *)) -
+ ALIGN(secctx_sz, sizeof(u64));
+ char *kptr = t->buffer->data + buf_offset;
+
+ t->security_ctx = (uintptr_t)kptr +
+ binder_alloc_get_user_buffer_offset(&target_proc->alloc);
+ memcpy(kptr, secctx, secctx_sz);
+ security_release_secctx(secctx, secctx_sz);
+ secctx = NULL;
+ }
t->buffer->debug_id = t->debug_id;
t->buffer->transaction = t;
t->buffer->target_node = target_node;
@@ -3272,6 +3305,9 @@
t->buffer->transaction = NULL;
binder_alloc_free_buf(&target_proc->alloc, t->buffer);
err_binder_alloc_buf_failed:
+ if (secctx)
+ security_release_secctx(secctx, secctx_sz);
+err_get_secctx_failed:
kfree(tcomplete);
binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
err_alloc_tcomplete_failed:
@@ -3922,11 +3958,13 @@
while (1) {
uint32_t cmd;
- struct binder_transaction_data tr;
+ struct binder_transaction_data_secctx tr;
+ struct binder_transaction_data *trd = &tr.transaction_data;
struct binder_work *w = NULL;
struct list_head *list = NULL;
struct binder_transaction *t = NULL;
struct binder_thread *t_from;
+ size_t trsize = sizeof(*trd);
binder_inner_proc_lock(proc);
if (!binder_worklist_empty_ilocked(&thread->todo))
@@ -4119,53 +4157,59 @@
struct binder_node *target_node = t->buffer->target_node;
struct binder_priority node_prio;
- tr.target.ptr = target_node->ptr;
- tr.cookie = target_node->cookie;
+ trd->target.ptr = target_node->ptr;
+ trd->cookie = target_node->cookie;
node_prio.sched_policy = target_node->sched_policy;
node_prio.prio = target_node->min_priority;
binder_transaction_priority(current, t, node_prio,
target_node->inherit_rt);
cmd = BR_TRANSACTION;
} else {
- tr.target.ptr = 0;
- tr.cookie = 0;
+ trd->target.ptr = 0;
+ trd->cookie = 0;
cmd = BR_REPLY;
}
- tr.code = t->code;
- tr.flags = t->flags;
- tr.sender_euid = from_kuid(current_user_ns(), t->sender_euid);
+ trd->code = t->code;
+ trd->flags = t->flags;
+ trd->sender_euid = from_kuid(current_user_ns(), t->sender_euid);
t_from = binder_get_txn_from(t);
if (t_from) {
struct task_struct *sender = t_from->proc->tsk;
- tr.sender_pid = task_tgid_nr_ns(sender,
- task_active_pid_ns(current));
+ trd->sender_pid =
+ task_tgid_nr_ns(sender,
+ task_active_pid_ns(current));
} else {
- tr.sender_pid = 0;
+ trd->sender_pid = 0;
}
- tr.data_size = t->buffer->data_size;
- tr.offsets_size = t->buffer->offsets_size;
- tr.data.ptr.buffer = (binder_uintptr_t)
+ trd->data_size = t->buffer->data_size;
+ trd->offsets_size = t->buffer->offsets_size;
+ trd->data.ptr.buffer = (binder_uintptr_t)
((uintptr_t)t->buffer->data +
binder_alloc_get_user_buffer_offset(&proc->alloc));
- tr.data.ptr.offsets = tr.data.ptr.buffer +
+ trd->data.ptr.offsets = trd->data.ptr.buffer +
ALIGN(t->buffer->data_size,
sizeof(void *));
+ tr.secctx = t->security_ctx;
+ if (t->security_ctx) {
+ cmd = BR_TRANSACTION_SEC_CTX;
+ trsize = sizeof(tr);
+ }
if (put_user(cmd, (uint32_t __user *)ptr)) {
if (t_from)
binder_thread_dec_tmpref(t_from);
return -EFAULT;
}
ptr += sizeof(uint32_t);
- if (copy_to_user(ptr, &tr, sizeof(tr))) {
+ if (copy_to_user(ptr, &tr, trsize)) {
if (t_from)
binder_thread_dec_tmpref(t_from);
return -EFAULT;
}
- ptr += sizeof(tr);
+ ptr += trsize;
trace_binder_transaction_received(t);
binder_stat_br(proc, thread, cmd);
@@ -4173,16 +4217,18 @@
"%d:%d %s %d %d:%d, cmd %d size %zd-%zd ptr %016llx-%016llx\n",
proc->pid, thread->pid,
(cmd == BR_TRANSACTION) ? "BR_TRANSACTION" :
- "BR_REPLY",
+ (cmd == BR_TRANSACTION_SEC_CTX) ?
+ "BR_TRANSACTION_SEC_CTX" : "BR_REPLY",
t->debug_id, t_from ? t_from->proc->pid : 0,
t_from ? t_from->pid : 0, cmd,
t->buffer->data_size, t->buffer->offsets_size,
- (u64)tr.data.ptr.buffer, (u64)tr.data.ptr.offsets);
+ (u64)trd->data.ptr.buffer,
+ (u64)trd->data.ptr.offsets);
if (t_from)
binder_thread_dec_tmpref(t_from);
t->buffer->allow_user_free = 1;
- if (cmd == BR_TRANSACTION && !(t->flags & TF_ONE_WAY)) {
+ if (cmd != BR_REPLY && !(t->flags & TF_ONE_WAY)) {
binder_inner_proc_lock(thread->proc);
t->to_parent = thread->transaction_stack;
t->to_thread = thread;
@@ -4510,7 +4556,8 @@
return ret;
}
-static int binder_ioctl_set_ctx_mgr(struct file *filp)
+static int binder_ioctl_set_ctx_mgr(struct file *filp,
+ struct flat_binder_object *fbo)
{
int ret = 0;
struct binder_proc *proc = filp->private_data;
@@ -4539,7 +4586,7 @@
} else {
context->binder_context_mgr_uid = curr_euid;
}
- new_node = binder_new_node(proc, NULL);
+ new_node = binder_new_node(proc, fbo);
if (!new_node) {
ret = -ENOMEM;
goto out;
@@ -4625,8 +4672,20 @@
binder_inner_proc_unlock(proc);
break;
}
+ case BINDER_SET_CONTEXT_MGR_EXT: {
+ struct flat_binder_object fbo;
+
+ if (copy_from_user(&fbo, ubuf, sizeof(fbo))) {
+ ret = -EINVAL;
+ goto err;
+ }
+ ret = binder_ioctl_set_ctx_mgr(filp, &fbo);
+ if (ret)
+ goto err;
+ break;
+ }
case BINDER_SET_CONTEXT_MGR:
- ret = binder_ioctl_set_ctx_mgr(filp);
+ ret = binder_ioctl_set_ctx_mgr(filp, NULL);
if (ret)
goto err;
break;
diff --git a/drivers/staging/android/uapi/binder.h b/drivers/staging/android/uapi/binder.h
index 712314f..384b824 100644
--- a/drivers/staging/android/uapi/binder.h
+++ b/drivers/staging/android/uapi/binder.h
@@ -86,6 +86,14 @@
* scheduling policy from the caller (for synchronous transactions).
*/
FLAT_BINDER_FLAG_INHERIT_RT = 0x800,
+
+ /**
+ * @FLAT_BINDER_FLAG_TXN_SECURITY_CTX: request security contexts
+ *
+ * Only when set, causes senders to include their security
+ * context
+ */
+ FLAT_BINDER_FLAG_TXN_SECURITY_CTX = 0x1000,
};
#ifdef BINDER_IPC_32BIT
@@ -253,6 +261,7 @@
#define BINDER_THREAD_EXIT _IOW('b', 8, __s32)
#define BINDER_VERSION _IOWR('b', 9, struct binder_version)
#define BINDER_GET_NODE_DEBUG_INFO _IOWR('b', 11, struct binder_node_debug_info)
+#define BINDER_SET_CONTEXT_MGR_EXT _IOW('b', 13, struct flat_binder_object)
/*
* NOTE: Two special error codes you should check for when calling
@@ -311,6 +320,11 @@
} data;
};
+struct binder_transaction_data_secctx {
+ struct binder_transaction_data transaction_data;
+ binder_uintptr_t secctx;
+};
+
struct binder_transaction_data_sg {
struct binder_transaction_data transaction_data;
binder_size_t buffers_size;
@@ -346,6 +360,11 @@
BR_OK = _IO('r', 1),
/* No parameters! */
+ BR_TRANSACTION_SEC_CTX = _IOR('r', 2,
+ struct binder_transaction_data_secctx),
+ /*
+ * binder_transaction_data_secctx: the received command.
+ */
BR_TRANSACTION = _IOR('r', 2, struct binder_transaction_data),
BR_REPLY = _IOR('r', 3, struct binder_transaction_data),
/*
