From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (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 BF02EFC0B for ; Thu, 3 Jul 2025 15:36:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751556963; cv=none; b=m+M3Z6SrAWhCOdmX3+rMgU0uegrMHZrQ594cHhMJ6bE0rP4VYxkQw/j1tgT6vXD5WGihV7XiUxypPgq5mvBWa6kVZl7BhIOstzrQEDIYxElZoOVTOk3pOTuVFtP9I+MEPnuPgHjvuB/RXztAkqx3k4dHopnbvP9mR1D6zKfQEnE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751556963; c=relaxed/simple; bh=+oQfP1Bds2NStfrSIzwtMkBJ7FoMmRtjt5wrpXL9d3Q=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=K1sahp/TV628358GODYNeeFVoEmI9BQlsV25tpzt+pTTMhiTevXmo4cqimhi/oNdIkRlyfOhgJ8J9Hnn3Fh78RFMn4I40BQuQNpqJw9/YecVXQ92OB+Xpef4jwTqM5CGFzTvfzrSDnBZLMhMqgBwKu2e4jOfnvs2qvNHEhE7PAo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=GACBzkMs; arc=none smtp.client-ip=91.218.175.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="GACBzkMs" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1751556958; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3eRVsX60PZyYuNbYRScH64M22xCUcDp+0crN+OJ6Ra4=; b=GACBzkMsaqWE1QUIRDa0I+YZATjc4bnBA0JsEmS4WRXa+o9tyjSx3wxSx+hQp+wZWsc3tc iE0f59L/CLG/8xpbC3B4Leen32Ruip8FrWE+mRvgxnYdwLeYBIPLTy0t61qMuB8+mWYnsQ wW9x6gUh88pwU2/DSjV3n5gQZtWnoho= Date: Thu, 3 Jul 2025 08:35:51 -0700 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next] bpf: Clean code with bpf_copy_to_user Content-Language: en-GB To: Tao Chen , ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250703124336.672416-1-chen.dylane@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yonghong Song In-Reply-To: <20250703124336.672416-1-chen.dylane@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 7/3/25 5:43 AM, Tao Chen wrote: > No logic change, just use bpf_copy_to_user to clean code. > > Signed-off-by: Tao Chen > --- > kernel/bpf/syscall.c | 17 +++-------------- > 1 file changed, 3 insertions(+), 14 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index e6eea594f1c..ca152d36312 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -5208,21 +5208,10 @@ static int bpf_task_fd_query_copy(const union bpf_attr *attr, > > if (put_user(zero, ubuf)) > return -EFAULT; > - } else if (input_len >= len + 1) { > - /* ubuf can hold the string with NULL terminator */ > - if (copy_to_user(ubuf, buf, len + 1)) > - return -EFAULT; > } else { > - /* ubuf cannot hold the string with NULL terminator, > - * do a partial copy with NULL terminator. > - */ > - char zero = '\0'; > - > - err = -ENOSPC; > - if (copy_to_user(ubuf, buf, input_len - 1)) > - return -EFAULT; > - if (put_user(zero, ubuf + input_len - 1)) > - return -EFAULT; > + err = bpf_copy_to_user(ubuf, buf, input_len, len); > + if (err) > + return err; > } > } Actually, there is a return value change with this patch. bpf_copy_to_user() return returns -ENOSPC while the original implementation may return -EFAULT due to following code. if (put_user(prog_id, &uattr->task_fd_query.prog_id) || put_user(fd_type, &uattr->task_fd_query.fd_type) || put_user(probe_offset, &uattr->task_fd_query.probe_offset) || put_user(probe_addr, &uattr->task_fd_query.probe_addr)) return -EFAULT; return err;