From c39bfcc6276d3e2c85fb805e226cc76a5c97573e Mon Sep 17 00:00:00 2001 From: Todd Kjos <tkjos@android.com> Date: Wed, 24 Apr 2019 12:31:18 -0700 Subject: [PATCH] [RAMEN9610-21231]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> --- drivers/android/binder.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index afa11e410d33..12ec925c954e 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3242,6 +3242,7 @@ static void binder_transaction(struct binder_proc *proc, 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); @@ -3251,7 +3252,15 @@ static void binder_transaction(struct binder_proc *proc, 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; + } } #ifdef CONFIG_DEBUG_SNAPSHOT_BINDER @@ -3559,6 +3568,7 @@ err_copy_data_failed: 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: -- 2.20.1