From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D544D1F8680; Tue, 17 Dec 2024 17:45:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734457528; cv=none; b=aenmFtNTBdXCeNXolA/gI04o3jltgRi5SXBPrOpdxWloA28baOLTSQGna4hd7794YOUOQ8PD83bMlZdtK2J5efld6HgGtkZUgBXfyoYCw91UtnJf8zVSQKOhipGtA8eRA4eq6MzmOklgYyLGpIinopKq5uxET+KE8fn36iSjH0Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734457528; c=relaxed/simple; bh=qnQRxzaxQCdy4sbeoonIrpEuwrhmpepXTvIte9AAxn0=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=RkOmmu21XD4SRIjLX0Rw0ZavN+lXgXCSqv2ELfrh0ydaFmdJk8hUI6NELuuXdeFo3VLvnuuuesn5aCCuWAiyGsG0dt0CEmWy/PRYUmV2xDFUOciKYnOhCwJEN3Eq0XN4ZoCJNjwl+iFh3da8HfxShL8EJ9vK/1fvkbCDokHsS/o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 517ECC4CED3; Tue, 17 Dec 2024 17:45:27 +0000 (UTC) Date: Tue, 17 Dec 2024 12:46:02 -0500 From: Steven Rostedt To: Edward Adam Davis Cc: syzbot+345e4443a21200874b18@syzkaller.appspotmail.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [PATCH] ring-buffer: Fix a oob in __rb_map_vma Message-ID: <20241217124602.2d498c3f@gandalf.local.home> In-Reply-To: References: <675fe376.050a0220.37aaf.011e.GAE@google.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 16 Dec 2024 22:07:57 +0800 Edward Adam Davis wrote: > syzbot report a slab-out-of-bounds in __rb_map_vma. [1] > > Overflow occurred when performing the following calculation: > nr_pages = ((nr_subbufs + 1) << subbuf_order) - pgoff; > > Add a check before the calculation to avoid this problem. > > [1] > BUG: KASAN: slab-out-of-bounds in __rb_map_vma+0x9ab/0xae0 kernel/trace/ring_buffer.c:7058 > Read of size 8 at addr ffff8880767dd2b8 by task syz-executor187/5836 > > CPU: 0 UID: 0 PID: 5836 Comm: syz-executor187 Not tainted 6.13.0-rc2-syzkaller-00159-gf932fb9b4074 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 > Call Trace: > > __dump_stack lib/dump_stack.c:94 [inline] > dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 > print_address_description mm/kasan/report.c:378 [inline] > print_report+0xc3/0x620 mm/kasan/report.c:489 > kasan_report+0xd9/0x110 mm/kasan/report.c:602 > __rb_map_vma+0x9ab/0xae0 kernel/trace/ring_buffer.c:7058 > ring_buffer_map+0x56e/0x9b0 kernel/trace/ring_buffer.c:7138 > tracing_buffers_mmap+0xa6/0x120 kernel/trace/trace.c:8482 > call_mmap include/linux/fs.h:2183 [inline] > mmap_file mm/internal.h:124 [inline] > __mmap_new_file_vma mm/vma.c:2291 [inline] > __mmap_new_vma mm/vma.c:2355 [inline] > __mmap_region+0x1786/0x2670 mm/vma.c:2456 > mmap_region+0x127/0x320 mm/mmap.c:1348 > do_mmap+0xc00/0xfc0 mm/mmap.c:496 > vm_mmap_pgoff+0x1ba/0x360 mm/util.c:580 > ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:542 > __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline] > __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline] > __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Reported-by: syzbot+345e4443a21200874b18@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=345e4443a21200874b18 > Tested-by: syzbot+345e4443a21200874b18@syzkaller.appspotmail.com > Signed-off-by: Edward Adam Davis > --- > kernel/trace/ring_buffer.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > index 7e257e855dd1..15c43d7415d5 100644 > --- a/kernel/trace/ring_buffer.c > +++ b/kernel/trace/ring_buffer.c > @@ -7019,6 +7019,9 @@ static int __rb_map_vma(struct ring_buffer_per_cpu *cpu_buffer, > lockdep_assert_held(&cpu_buffer->mapping_lock); > > nr_subbufs = cpu_buffer->nr_pages + 1; /* + reader-subbuf */ > + if (((nr_subbufs + 1) << subbuf_order) < pgoff) > + return -EINVAL; > + A proper fix is being discussed here: https://lore.kernel.org/linux-trace-kernel/20241216164931.57323-1-aha310510@gmail.com/ Thank you, -- Steve > nr_pages = ((nr_subbufs + 1) << subbuf_order) - pgoff; /* + meta-page */ > > nr_vma_pages = vma_pages(vma);