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binder: fix potential UAF of target_{proc,thread}

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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 <dan.carpenter@oracle.com>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220517185817.598872-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Carlos Llamas 2022-05-17 18:58:17 +00:00 committed by Greg Kroah-Hartman
parent da4864962d
commit dafa5e9ab8
1 changed files with 5 additions and 4 deletions
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9
drivers/android/binder.c
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@ -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;