From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0A5CC433EF for ; Mon, 16 May 2022 23:05:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350178AbiEPXFo (ORCPT ); Mon, 16 May 2022 19:05:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350200AbiEPXFf (ORCPT ); Mon, 16 May 2022 19:05:35 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 26A0946B19 for ; Mon, 16 May 2022 16:05:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652742331; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=/PrpIF0lAA7w2fu9g8XdUbK+AXcZafepF1JXwFuF0QE=; b=VXsBsED4kne1ikSBSQH9TFOK83oA0c5aYmO1wIiHhYam9bvkSYbQw0MzFjHsALUlReJuLC 6jvv7c7cztP3kzqiiCdBsNwJgTHQDV/UHpopVXOSzwI9N+kRNWFm48ZccUVWsqIj+nPwHU O7v2Somo9Tjr9csl7TdiHq0uNdB7cDQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-442-ZlOt9hVaPm6IfjLVuzpThA-1; Mon, 16 May 2022 19:05:25 -0400 X-MC-Unique: ZlOt9hVaPm6IfjLVuzpThA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C9BCC801210; Mon, 16 May 2022 23:05:24 +0000 (UTC) Received: from asgard.redhat.com (unknown [10.36.110.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D83CF400E122; Mon, 16 May 2022 23:05:20 +0000 (UTC) Date: Tue, 17 May 2022 01:05:17 +0200 From: Eugene Syromiatnikov To: Jiri Olsa , Masami Hiramatsu , Steven Rostedt , Ingo Molnar , Alexei Starovoitov , Daniel Borkmann Cc: Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Shuah Khan , linux-kselftest@vger.kernel.org Subject: [PATCH bpf v2 3/4] bpf_trace: handle compat in kprobe_multi_resolve_syms Message-ID: <20220516230517.GA25568@asgard.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For compat processes, userspace pointer size is different. Since the copied array is iterated anyway, the simplest fix seems to be copy the user-supplied array as-is and the iterate as an array of native or compat pointers, depending on the in_compat_syscall() value. Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link") Signed-off-by: Eugene Syromiatnikov --- kernel/trace/bpf_trace.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index bf5bcfb..268c92b 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2353,16 +2353,19 @@ kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt, unsigned long *addrs) { unsigned long addr, sym_size; - u32 size; + u32 size, elem_size; const char __user **syms; + compat_uptr_t __user *compat_syms; int err = -ENOMEM; unsigned int i; char *func; - if (check_mul_overflow(cnt, (u32)sizeof(*syms), &size)) + elem_size = in_compat_syscall() ? sizeof(*compat_syms) : sizeof(*syms); + if (check_mul_overflow(cnt, elem_size, &size)) return -EOVERFLOW; - size = cnt * sizeof(*syms); + size = cnt * elem_size; syms = kvzalloc(size, GFP_KERNEL); + compat_syms = (void *)syms; if (!syms) return -ENOMEM; @@ -2376,7 +2379,10 @@ kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt, } for (i = 0; i < cnt; i++) { - err = strncpy_from_user(func, syms[i], KSYM_NAME_LEN); + const char __user *ufunc = in_compat_syscall() + ? (char __user *)(uintptr_t)compat_syms[i] + : syms[i]; + err = strncpy_from_user(func, ufunc, KSYM_NAME_LEN); if (err == KSYM_NAME_LEN) err = -E2BIG; if (err < 0) -- 2.1.4