From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF7E92D6E7A for ; Sat, 25 Oct 2025 10:07:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761386825; cv=none; b=m0Q/WV8jXg/70pwOavuQSEhyp+Se+zEWikA+AxJocpFDsjDFUeIakweU4KzwjUt138KzcHQ8Q82H+ATgxNEEJUekZ1+o1v1Hcw4z+varWybCaidA5baoLRIXW3aeaomnpKZ0xDL3Q0YUR2g6RMOgqhfXDrER2b6/xDYxfLZpK9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761386825; c=relaxed/simple; bh=/nkvwQcQOUseZCfuA5/TaYOK82Tbt6IRGSTD7moFW4A=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OWA5z9H+pfbqlFTzL2TXdgVsIWG7/hKoBf/lmkXnNRNXqxRXNS+LgetDonW2UpYObdfQl9D/1vjYJ3z+6IwcW4bVMlGBZfOj9CvoihJhjlSXHtjk3nwvqCg+znv23hHGyk0HXko/6NbGbfDs+A3Vsw/NAx21UgnYCDFosBgMGIw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=LVY7o8qr; arc=none smtp.client-ip=209.85.128.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="LVY7o8qr" Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-47117f92e32so26569065e9.1 for ; Sat, 25 Oct 2025 03:07:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1761386821; x=1761991621; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=ffKrW4JJrj3VHxVVjDqJDojj1sAYTEf4Ex+dz329C6w=; b=LVY7o8qr8b62fD2ja4wY358UNXMN4lOtWgAfqngfLV6z32Xkum2dJuIcO1oA5ZiJBB Xno1eQ0H9C5uLW/mR4sAfahps/NczNy5NgK4X7jP7zAvDDJ1NSnD1P3EmAooQJF/mX/1 67J/ZLIya0BTnBTztQs7AC7kafcxyXiDkrXMceVpvKb9nVBw/kPbnxVM3s8GF/PxVbLz I+J4f/qPGJ2LJb7E8mYEXeDEbpdlGAv+wCeDbfUN+N6dkafIvSqQmPnRFXCgKedRjk75 cZ8L1cWOoqkYfh2qkj+X2rc8tOa5Of97oGDO1Lr57hZ7LN+5945jqrvcm6Fbum3yyYtT lVpA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761386821; x=1761991621; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=ffKrW4JJrj3VHxVVjDqJDojj1sAYTEf4Ex+dz329C6w=; b=ONk+P+DxplABrYCLEyWgUyA8GbeIENmhtU2ax5w/lXOPxpLq3xnahIDrKKC2L6KMyL 5/ssj06nnHJ0Rqo1bMp1474EAS8sfEUhcCmDdFFEyPM1zNzYRZU6S7qopsNa/3CQ88xc JPf9+2XqlgBepmnb+7FWwY24q9RTmKrwheybbhlPFHFgt5GSPC42Mnrr68dJuPPVZThN axvCx72LJ0GErVnTm6bI13UjZVWmq9M1F85XWCIWgdaCQWI8FopkrWf2Eas7k0sT1+32 k0ujnu4CxxkOwsmEa0X/Zfv43jPh2sxu6Mi/PfHqitYx/5r0AOtm0FDF8wNyTenSpUIj bVig== X-Forwarded-Encrypted: i=1; AJvYcCUDUze3o959OH3w6U3swvd6bnms7fDVVnsfHLJlPmlrB36KbiXVgIpAmT270nvtw9i6wCk/M66p2Ujkjg==@vger.kernel.org X-Gm-Message-State: AOJu0YzBLyfxUrB/ZY3U6kyH4IRqAiEvtozIx6pomxp/vrIcErS/G9vz tOdIq2+j2BaCK9eb81kK2oiTQza2IbWsGJe9cK95GfUTAzJ8bc1aI7yYmvcQPJGN3uE= X-Gm-Gg: ASbGnctMKM6i3jVH0FDjLDLxSwhrXWHFpcPu/IvRTx1z2+ND50ogEgng9V6m3CvtX0A uqBVTL6RrEPSmyExOn8NTW5IktcaOtpMItx5jb4wl9kBavZ/x9yUN5QFSvuVn3KSEhaYdv26OZv atHbKqoCmFn2zmAIDhrFuPFfNEP8uvkEqiZLmc0j/gWTaJvt0TYpuVoTnQvzot4278wtsG0oYcX eHlrdRPEXOLdYbBwiTjITMK0eq2UUXStmH3EXzNxA6v2HEprTZ2TejCF/XohXMB9wFK3O77Z8u7 0HPRMiSJnHYS/+Ipzqepri9XqOhFDt9E19Th3n4ijvFmKsWOMtO5c4tXWmUon6WsJ1sgbV956f2 ROwYD7DeXie3bCet7xsUMWxjnqv9gncwevzVggiVgC+Il+WLnB7hoR6StNRFWHPUncvSpuguQBV 0u1kAm3X8VtyXtZ81UlYIv+54lbudD X-Google-Smtp-Source: AGHT+IHchT8Z4oQ1De1jwRykmWf+L8ypsYopyNQhR9SYSssq2RNZbs9gtAznCWckyDwsQYkLDQzmbw== X-Received: by 2002:a05:600c:8b71:b0:475:f16f:6f44 with SMTP id 5b1f17b1804b1-475f16f737bmr5258505e9.27.1761386820858; Sat, 25 Oct 2025 03:07:00 -0700 (PDT) Received: from ?IPV6:2403:580d:fda1::299? (2403-580d-fda1--299.ip6.aussiebb.net. [2403:580d:fda1::299]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-b7127a0a2f9sm1696657a12.9.2025.10.25.03.06.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 25 Oct 2025 03:07:00 -0700 (PDT) Message-ID: <293c10e8-fa6b-4da2-8d7d-9eaf6b4ecd4b@suse.com> Date: Sat, 25 Oct 2025 20:36:56 +1030 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH fs/btrfs] btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation To: Shardul Bankar , linux-btrfs@vger.kernel.org Cc: clm@fb.com, dsterba@suse.com, linux-kernel@vger.kernel.org References: <20251025092951.2866847-1-shardulsb08@gmail.com> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=wqu@suse.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNGFF1IFdlbnJ1byA8d3F1QHN1c2UuY29tPsLAlAQTAQgAPgIbAwULCQgHAgYVCAkKCwIE FgIDAQIeAQIXgBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXVgBQkQ/lqxAAoJEMI9kfOh Jf6o+jIH/2KhFmyOw4XWAYbnnijuYqb/obGae8HhcJO2KIGcxbsinK+KQFTSZnkFxnbsQ+VY fvtWBHGt8WfHcNmfjdejmy9si2jyy8smQV2jiB60a8iqQXGmsrkuR+AM2V360oEbMF3gVvim 2VSX2IiW9KERuhifjseNV1HLk0SHw5NnXiWh1THTqtvFFY+CwnLN2GqiMaSLF6gATW05/sEd V17MdI1z4+WSk7D57FlLjp50F3ow2WJtXwG8yG8d6S40dytZpH9iFuk12Sbg7lrtQxPPOIEU rpmZLfCNJJoZj603613w/M8EiZw6MohzikTWcFc55RLYJPBWQ+9puZtx1DopW2jOwE0EWdWB rwEIAKpT62HgSzL9zwGe+WIUCMB+nOEjXAfvoUPUwk+YCEDcOdfkkM5FyBoJs8TCEuPXGXBO Cl5P5B8OYYnkHkGWutAVlUTV8KESOIm/KJIA7jJA+Ss9VhMjtePfgWexw+P8itFRSRrrwyUf E+0WcAevblUi45LjWWZgpg3A80tHP0iToOZ5MbdYk7YFBE29cDSleskfV80ZKxFv6koQocq0 vXzTfHvXNDELAuH7Ms/WJcdUzmPyBf3Oq6mKBBH8J6XZc9LjjNZwNbyvsHSrV5bgmu/THX2n g/3be+iqf6OggCiy3I1NSMJ5KtR0q2H2Nx2Vqb1fYPOID8McMV9Ll6rh8S8AEQEAAcLAfAQY AQgAJgIbDBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXWBBQkQ/lrSAAoJEMI9kfOhJf6o cakH+QHwDszsoYvmrNq36MFGgvAHRjdlrHRBa4A1V1kzd4kOUokongcrOOgHY9yfglcvZqlJ qfa4l+1oxs1BvCi29psteQTtw+memmcGruKi+YHD7793zNCMtAtYidDmQ2pWaLfqSaryjlzR /3tBWMyvIeWZKURnZbBzWRREB7iWxEbZ014B3gICqZPDRwwitHpH8Om3eZr7ygZck6bBa4MU o1XgbZcspyCGqu1xF/bMAY2iCDcq6ULKQceuKkbeQ8qxvt9hVxJC2W3lHq8dlK1pkHPDg9wO JoAXek8MF37R8gpLoGWl41FIUb3hFiu3zhDDvslYM4BmzI18QgQTQnotJH8= In-Reply-To: <20251025092951.2866847-1-shardulsb08@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2025/10/25 19:59, Shardul Bankar 写道: > When btrfs_add_qgroup_relation() is called with invalid qgroup levels > (src >= dst), the function returns -EINVAL directly without freeing the > preallocated qgroup_list structure passed by the caller. This causes a > memory leak because the caller unconditionally sets the pointer to NULL > after the call, preventing any cleanup. > > The issue occurs because the level validation check happens before the > mutex is acquired and before any error handling path that would free > the prealloc pointer. On this early return, the cleanup code at the > 'out' label (which includes kfree(prealloc)) is never reached. > > In btrfs_ioctl_qgroup_assign(), the code pattern is: > > prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL); > ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc); > prealloc = NULL; // Always set to NULL regardless of return value > ... > kfree(prealloc); // This becomes kfree(NULL), does nothing > > When the level check fails, 'prealloc' is never freed by either the > callee or the caller, resulting in a 64-byte memory leak per failed > operation. This can be triggered repeatedly by an unprivileged user > with access to a writable btrfs mount, potentially exhausting kernel > memory. > > Fix this by changing the early return to a goto that reaches the > cleanup code, ensuring prealloc is always freed on all error paths. > > Reported-by: BRF (btrfs runtime fuzzer) > Fixes: 8465ecec9611 ("btrfs: Check qgroup level in kernel qgroup assign.") > Signed-off-by: Shardul Bankar > --- > fs/btrfs/qgroup.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c > index 1175b8192cd7..0a25bfdd442f 100644 > --- a/fs/btrfs/qgroup.c > +++ b/fs/btrfs/qgroup.c > @@ -1539,8 +1539,10 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src, u64 dst > ASSERT(prealloc); > > /* Check the level of src and dst first */ > - if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst)) > - return -EINVAL; > + if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst)) { > + ret = -EINVAL; > + goto out; > + } Out will call mutex_unlock(), but we haven't yet even locked the mutex. Please just call kfree(prealloc) then return. Thanks, Qu > > mutex_lock(&fs_info->qgroup_ioctl_lock); > if (!fs_info->quota_root) {