From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout11.his.huawei.com (frasgout11.his.huawei.com [14.137.139.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EED0715CD74; Fri, 18 Oct 2024 11:23:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=14.137.139.23 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729250592; cv=none; b=M0An7t1iahYkyNb+I1dfqNHUZfEUFBLZNl88rGHs6N3JYN6MScM1lfdspjRfJgFSLzu73qxKu6X3eZn1upgH3Nj3CXCjG6rk7WvDpXIXaij5FDotac9adJITuiVGbFkHsyZBpUUwf2llf+S8vHW0iuX+tGfjRajQli+ugtTsQko= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729250592; c=relaxed/simple; bh=D1I/4ufMNbS+r7m8JyIKgUN6UCBipqdvyYRQ+PuBwU4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=rw/tnYyE5qb+BY2Lpn9olA9iVyfMXA8MkqossL3NdcG0ri7KKRQPtBAJQABqZ3SK+OpnBc7U2zPyx70FKNEQvqsYgU0/v3ScBN2RyEyotYFCSwB5kx8wPVqvNUxwp21gX7BJTK1SyUnjedeoR9SW7sQxMbLHOMThoTORzcPnFq8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=14.137.139.23 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.18.186.29]) by frasgout11.his.huawei.com (SkyGuard) with ESMTP id 4XVMHS1jg7z9v7Hm; Fri, 18 Oct 2024 19:02:44 +0800 (CST) Received: from mail02.huawei.com (unknown [7.182.16.47]) by mail.maildlp.com (Postfix) with ESMTP id 41F851405A1; Fri, 18 Oct 2024 19:22:51 +0800 (CST) Received: from [127.0.0.1] (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwDHWDD+RBJnJOwWAw--.51604S2; Fri, 18 Oct 2024 12:22:50 +0100 (CET) Message-ID: Subject: Re: [PATCH 1/3] ima: Remove inode lock From: Roberto Sassu To: "Kirill A. Shutemov" , Lorenzo Stoakes Cc: Paul Moore , ebpqwerty472123@gmail.com, kirill.shutemov@linux.intel.com, zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, eric.snowberg@oracle.com, jmorris@namei.org, serge@hallyn.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, Roberto Sassu , linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, linux-fsdevel@vger.kernel.org, Liam Howlett , Jann Horn Date: Fri, 18 Oct 2024 13:22:35 +0200 In-Reply-To: References: <20241008165732.2603647-1-roberto.sassu@huaweicloud.com> <7358f12d852964d9209492e337d33b8880234b74.camel@huaweicloud.com> <593282dbc9f48673c8f3b8e0f28e100f34141115.camel@huaweicloud.com> <15bb94a306d3432de55c0a12f29e7ed2b5fa3ba1.camel@huaweicloud.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4-0ubuntu2 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID:LxC2BwDHWDD+RBJnJOwWAw--.51604S2 X-Coremail-Antispam: 1UD129KBjvJXoWxuF13JFWrJw1fuF43Jw4Utwb_yoW5CFyfpr yrJ3WqgFWYqF1xJrn2q3Z0gFn8t34UKFy7WrWrXry8AwnFqF13Cr4rGFy5urs8Ar1kAFyr ZF4UCFZIkay7JFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvjb4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AF wI0_GFv_Wryl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4 xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5 MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I 0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWU JVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUIa 0PDUUUU X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAgAABGcRxH8HrQAEsl On Fri, 2024-10-18 at 14:05 +0300, Kirill A. Shutemov wrote: > On Fri, Oct 18, 2024 at 12:00:22PM +0100, Lorenzo Stoakes wrote: > > + Liam, Jann > >=20 > > On Fri, Oct 18, 2024 at 01:49:06PM +0300, Kirill A. Shutemov wrote: > > > On Fri, Oct 18, 2024 at 11:24:06AM +0200, Roberto Sassu wrote: > > > > Probably it is hard, @Kirill would there be any way to safely move > > > > security_mmap_file() out of the mmap_lock lock? > > >=20 > > > What about something like this (untested): > > >=20 > > > diff --git a/mm/mmap.c b/mm/mmap.c > > > index dd4b35a25aeb..03473e77d356 100644 > > > --- a/mm/mmap.c > > > +++ b/mm/mmap.c > > > @@ -1646,6 +1646,26 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned lon= g, start, unsigned long, size, > > > if (pgoff + (size >> PAGE_SHIFT) < pgoff) > > > return ret; > > >=20 > > > + if (mmap_read_lock_killable(mm)) > > > + return -EINTR; > > > + > > > + vma =3D vma_lookup(mm, start); > > > + > > > + if (!vma || !(vma->vm_flags & VM_SHARED)) { > > > + mmap_read_unlock(mm); > > > + return -EINVAL; > > > + } > > > + > > > + file =3D get_file(vma->vm_file); > > > + > > > + mmap_read_unlock(mm); > > > + > > > + ret =3D security_mmap_file(vma->vm_file, prot, flags); > >=20 > > Accessing VMA fields without any kind of lock is... very much not advis= ed. > >=20 > > I'm guessing you meant to say: > >=20 > > ret =3D security_mmap_file(file, prot, flags); > >=20 > > Here? :) >=20 > Sure. My bad. >=20 > Patch with all fixups: Thanks a lot! Let's wait a bit until the others have a chance to comment. Meanwhile, I will test it. Do you want me to do the final patch, or will you be proposing it? Roberto > diff --git a/mm/mmap.c b/mm/mmap.c > index dd4b35a25aeb..541787d526b6 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1646,14 +1646,41 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, = start, unsigned long, size, > if (pgoff + (size >> PAGE_SHIFT) < pgoff) > return ret; > =20 > - if (mmap_write_lock_killable(mm)) > + if (mmap_read_lock_killable(mm)) > return -EINTR; > =20 > vma =3D vma_lookup(mm, start); > =20 > + if (!vma || !(vma->vm_flags & VM_SHARED)) { > + mmap_read_unlock(mm); > + return -EINVAL; > + } > + > + file =3D get_file(vma->vm_file); > + > + mmap_read_unlock(mm); > + > + ret =3D security_mmap_file(file, prot, flags); > + if (ret) { > + fput(file); > + return ret; > + } > + > + ret =3D -EINVAL; > + > + if (mmap_write_lock_killable(mm)) { > + fput(file); > + return -EINTR; > + } > + > + vma =3D vma_lookup(mm, start); > + > if (!vma || !(vma->vm_flags & VM_SHARED)) > goto out; > =20 > + if (vma->vm_file !=3D file) > + goto out; > + > if (start + size > vma->vm_end) { > VMA_ITERATOR(vmi, mm, vma->vm_end); > struct vm_area_struct *next, *prev =3D vma; > @@ -1688,16 +1715,11 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, = start, unsigned long, size, > if (vma->vm_flags & VM_LOCKED) > flags |=3D MAP_LOCKED; > =20 > - file =3D get_file(vma->vm_file); > - ret =3D security_mmap_file(vma->vm_file, prot, flags); > - if (ret) > - goto out_fput; > ret =3D do_mmap(vma->vm_file, start, size, > prot, flags, 0, pgoff, &populate, NULL); > -out_fput: > - fput(file); > out: > mmap_write_unlock(mm); > + fput(file); > if (populate) > mm_populate(ret, populate); > if (!IS_ERR_VALUE(ret))