Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F031538655A; Sat, 12 Sep 2026 13:09:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789218591; cv=none; b=RFJ9D1qHKmYVlVuAd2bzxzec/qekCJCeqd6mtEq1jnS6h6YN51xDR74Ets7xECcN5MCUES2X2wv26V7HGzp1scAHhyAhwCFoJT1shYPKhfTViEI5H/L2vPXeNlbMWT6k/jScvW9IUhUUw9/OpF6H36OLFb3oqHa0/s+WvaU5hGI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789218591; c=relaxed/simple; bh=yFadao9T+1L5AxvCGm3noJgqWmuzh89/spvC7pb5pvA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hUFqaWCVqg/cbVt/v36Y4nsMx/IkqPvB22oMOZ9zBvHNNZkUNCCUe0+6LRgkciQt6hNkCflwV6cccD5PwuDvflDtrBgPETFxzAqL9mjTA8cRMXTQBeLxt6RQHtEPsWZUBqj1M0h1Bz6sfYsfKrDasHxA2IrXjPEcM1dOIGkqL44= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=U+l0ezL5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="U+l0ezL5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC6FE1F000FF; Sat, 12 Sep 2026 13:09:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789218589; bh=REMIpLYTsaV205XiUgQUwgUsRiBZ5j3oh1gcN41PlMo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=U+l0ezL5lYVddd6zousyzYSsCQV6M7PEskFVL8krwM2x3RzPM8vuC3HVHqyGmjdiX W5CnD9eyzOqrBS1moDkJHzwUJGWFdilQe7pT0CZaQTADlYA//Vq0GWTUhUlteFfFdM mni6OJz+lpa4TnUfoaOIZeCJPpy4N/fmEVOLVQPw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sechang Lim , Junseo Lim , Daniel Borkmann , Emil Tsalapatis , Sasha Levin Subject: [PATCH 6.12 1176/1376] bpf: Reject negative optlen in cgroup getsockopt hook Date: Sat, 12 Sep 2026 09:00:02 +0200 Message-ID: <20260912065633.761715790@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Junseo Lim [ Upstream commit 1b5aacd5b2419b0790e955e466d389a61c79b4b1 ] A cgroup getsockopt BPF program can shrink ctx->optlen after the kernel getsockopt handler has run. The kernel-buffer variant, used by TCP_ZEROCOPY_RECEIVE, only rejects values larger than the original length. If BPF writes a negative optlen, that value is accepted and propagated back to the TCP getsockopt code. It can then be passed to copy_to_sockptr() as a size_t and trigger the hardened usercopy bytes > INT_MAX warning. Reject negative ctx.optlen in __cgroup_bpf_run_filter_getsockopt_kern(), matching the lower-bound validation already present in the sockptr-based getsockopt hook. Fixes: 9cacf81f8161 ("bpf: Remove extra lock_sock for TCP_ZEROCOPY_RECEIVE") Reported-by: Sechang Lim Signed-off-by: Junseo Lim Signed-off-by: Daniel Borkmann Reviewed-by: Emil Tsalapatis Link: https://lore.kernel.org/bpf/187a4d756275aaaee5d65eecb63c1477b3b66554.1786448307.git.zirajs7@gmail.com Signed-off-by: Sasha Levin --- kernel/bpf/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index e2d352251bb71..fa2b9f033d84e 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -2214,7 +2214,7 @@ int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level, if (ret < 0) return ret; - if (ctx.optlen > *optlen) + if (ctx.optlen > *optlen || ctx.optlen < 0) return -EFAULT; /* BPF programs can shrink the buffer, export the modifications. -- 2.53.0