binder: Address corner cases in deferred copy and fixup
stable inclusion from stable-v5.10.157 commit 017de842533f4334d646f1d480f591f4ca9f5c7a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6DKVG CVE: CVE-2023-20938 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=017de842533f4334d646f1d480f591f4ca9f5c7a -------------------------------- commit 2d1746e3 upstream. When handling BINDER_TYPE_FDA object we are pushing a parent fixup with a certain skip_size but no scatter-gather copy object, since the copy is handled standalone. If BINDER_TYPE_FDA is the last children the scatter-gather copy loop will never stop to skip it, thus we are left with an item in the parent fixup list. This will trigger the BUG_ON(). This is reproducible in android when playing a video. We receive a transaction that looks like this: obj[0] BINDER_TYPE_PTR, parent obj[1] BINDER_TYPE_PTR, child obj[2] BINDER_TYPE_PTR, child obj[3] BINDER_TYPE_FDA, child Fixes: 09184ae9 ("binder: defer copies of pre-patched txn data") Acked-by: NTodd Kjos <tkjos@google.com> Cc: stable <stable@kernel.org> Signed-off-by: NAlessandro Astone <ales.astone@gmail.com> Link: https://lore.kernel.org/r/20220415120015.52684-2-ales.astone@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: NCarlos Llamas <cmllamas@google.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: NLi Huafei <lihuafei1@huawei.com> Reviewed-by: NZheng Yejian <zhengyejian1@huawei.com> Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
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