UPSTREAM: binder: check for overflow when alloc for security context
commit 0b0509508beff65c1d50541861bc0d4973487dc5 upstream.
When allocating space in the target buffer for the security context,
make sure the extra_buffers_size doesn't overflow. This can only
happen if the given size is invalid, but an overflow can turn it
into a valid size. Fail the transaction if an overflow is detected.
Bug: 130571081
Change-Id: Ibaec652d2073491cc426a4a24004a848348316bf
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 64824dc..20f15b8 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3228,6 +3228,7 @@
if (target_node && target_node->txn_security_ctx) {
u32 secid;
+ size_t added_size;
security_task_getsecid(proc->tsk, &secid);
ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
@@ -3237,7 +3238,15 @@
return_error_line = __LINE__;
goto err_get_secctx_failed;
}
- extra_buffers_size += ALIGN(secctx_sz, sizeof(u64));
+ added_size = ALIGN(secctx_sz, sizeof(u64));
+ extra_buffers_size += added_size;
+ if (extra_buffers_size < added_size) {
+ /* integer overflow of extra_buffers_size */
+ return_error = BR_FAILED_REPLY;
+ return_error_param = EINVAL;
+ return_error_line = __LINE__;
+ goto err_bad_extra_size;
+ }
}
trace_binder_transaction(reply, t, target_node);
@@ -3586,6 +3595,7 @@
t->buffer->transaction = NULL;
binder_alloc_free_buf(&target_proc->alloc, t->buffer);
err_binder_alloc_buf_failed:
+err_bad_extra_size:
if (secctx)
security_release_secctx(secctx, secctx_sz);
err_get_secctx_failed: