Carlos Llamas 3ce00bb7e9 binder: validate alloc->mm in ->mmap() handler ... Since commit 1da52815d5 ("binder: fix alloc->vma_vm_mm null-ptr dereference") binder caches a pointer to the current->mm during open(). This fixes a null-ptr dereference reported by syzkaller. Unfortunately, it also opens the door for a process to update its mm after the open(), (e.g. via execve) making the cached alloc->mm pointer invalid. Things get worse when the process continues to mmap() a vma. From this point forward, binder will attempt to find this vma using an obsolete alloc->mm reference. Such as in binder_update_page_range(), where the wrong vma is obtained via vma_lookup(), yet binder proceeds to happily insert new pages into it. To avoid this issue fail the ->mmap() callback if we detect a mismatch between the vma->vm_mm and the original alloc->mm pointer. This prevents alloc->vm_addr from getting set, so that any subsequent vma_lookup() calls fail as expected. Fixes: 1da52815d5 ("binder: fix alloc->vma_vm_mm null-ptr dereference") Reported-by: Jann Horn <jannh@google.com> Cc: <stable@vger.kernel.org> # 5.15+ Signed-off-by: Carlos Llamas <cmllamas@google.com> Acked-by: Todd Kjos <tkjos@google.com> Link: https://lore.kernel.org/r/20221104231235.348958-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-11-09 15:41:27 +01:00
..
Kconfig	remove CONFIG_ANDROID	2022-07-01 10:41:09 +02:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
binder.c	Scheduler changes for v6.1:	2022-10-10 09:10:28 -07:00
binder_alloc.c	binder: validate alloc->mm in ->mmap() handler	2022-11-09 15:41:27 +01:00
binder_alloc.h	binder: fix binder_alloc kernel-doc warnings	2022-09-06 17:02:06 +02:00
binder_alloc_selftest.c	android: binder: stop saving a pointer to the VMA	2022-07-29 18:07:13 -07:00
binder_internal.h	binder: fix redefinition of seq_file attributes	2022-07-08 15:44:19 +02:00
binder_trace.h	Binder: add TF_UPDATE_TXN to replace outdated txn	2022-06-27 16:16:30 +02:00
binderfs.c	binderfs: rework superblock destruction	2022-09-01 16:18:49 +02:00