From dafa5e9ab8b5b31d64c0ded188d95f8bb6be9746 Mon Sep 17 00:00:00 2001 From: Carlos Llamas Date: Tue, 17 May 2022 18:58:17 +0000 Subject: binder: fix potential UAF of target_{proc,thread} Commit 9474be34a727 ("binder: add failed transaction logging info") dereferences target_{proc,thread} after they have been potentially freed by binder_proc_dec_tmpref() and binder_thread_dec_tmpref(). This patch delays the release of the two references after their last usage. Fixes the following two errors reported by smatch: drivers/android/binder.c:3562 binder_transaction() error: dereferencing freed memory 'target_proc' drivers/android/binder.c:3563 binder_transaction() error: dereferencing freed memory 'target_thread' Fixes: 9474be34a727 ("binder: add failed transaction logging info") Reported-by: Dan Carpenter Acked-by: Todd Kjos Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20220517185817.598872-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'drivers/android') diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 176bb0463680..9e36608eac6c 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3546,10 +3546,6 @@ err_bad_call_stack: err_empty_call_stack: err_dead_binder: err_invalid_target_handle: - if (target_thread) - binder_thread_dec_tmpref(target_thread); - if (target_proc) - binder_proc_dec_tmpref(target_proc); if (target_node) { binder_dec_node(target_node, 1, 0); binder_dec_node_tmpref(target_node); @@ -3565,6 +3561,11 @@ err_invalid_target_handle: (u64)tr->data_size, (u64)tr->offsets_size, return_error_line); + if (target_thread) + binder_thread_dec_tmpref(target_thread); + if (target_proc) + binder_proc_dec_tmpref(target_proc); + { struct binder_transaction_log_entry *fe; -- cgit v1.2.3