From mboxrd@z Thu Jan 1 00:00:00 1970 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 6E6593164C3; Wed, 20 May 2026 16:52:32 +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=1779295953; cv=none; b=JUGat/YQfA/Nx62oNjuEHOtgF9VRUedO7TRHJSphvYVL0pLgEDMv31r2FmIpUlPjp5if6uishov1Dena6wPW+Kq4iyyLKA3R4J/07y71axAohQ/fIHQQRMYvDBhucjP2yaYBxe9cxDjtH3UnLB22HyjMbOL9AwTNfNFFbyfxUx8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779295953; c=relaxed/simple; bh=gBed/N+d4kujpxU32M9fgmoMWGoaP6BV0YJp3yLzBtw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jVJJXAu3hJmHScP50gVD5jDTya5DEjInbKgUNPCGoLV5gUl1SQmSsOFiR62b4SPPPGP/qDg4Ean/gnk8xr4LGIZH2YaGtX9KTPLxYUeDQMFW8F9TdVHjFyaEho3uZMkZLGvHEVwVgvxtrvLeSmmtyhytF8ZyLfFb3SaUkxvsndM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=N5aky5f5; 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="N5aky5f5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D35F41F000E9; Wed, 20 May 2026 16:52:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779295952; bh=SEpqY6+gs7JQreNFh2eta5dUSynZ353X86Jk96NLluw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=N5aky5f5J21VV8siYHlFSSpcNvOWMpUvlKZIIWyliQ7My5yzhjLvR7iAMqV178eRI Zfa+YS1N8f1gBhBIHylbzWEfswYdglxH8DeTg5REE51554K/3U2W6BIrnUzPsl5NVN nxbl7njR1lC5ASnAPbEF1hLHGMym8RgASniX8CLU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Daniel Borkmann , Alexei Starovoitov , Sasha Levin Subject: [PATCH 7.0 0616/1146] bpf: Fix precedence bug in convert_bpf_ld_abs alignment check Date: Wed, 20 May 2026 18:14:26 +0200 Message-ID: <20260520162202.124475252@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162148.390695140@linuxfoundation.org> References: <20260520162148.390695140@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 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit e5f635edd393aeaa7cad9e42831d397e6e2e1eed ] Fix an operator precedence issue in convert_bpf_ld_abs() where the expression offset + ip_align % size evaluates as offset + (ip_align % size) due to % having higher precedence than +. That latter evaluation does not make any sense. The intended check is (offset + ip_align) % size == 0 to verify that the packet load offset is properly aligned for direct access. With NET_IP_ALIGN == 2, the bug causes the inline fast-path for direct packet loads to almost never be taken on !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS platforms. This forces nearly all cBPF BPF_LD_ABS packet loads through the bpf_skb_load_helper slow path on the affected archs. Fixes: e0cea7ce988c ("bpf: implement ld_abs/ld_ind in native bpf") Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20260416122719.661033-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- net/core/filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index 90ae4f314b6c3..d4fe9e4a45d11 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -508,7 +508,7 @@ static bool convert_bpf_ld_abs(struct sock_filter *fp, struct bpf_insn **insnp) ((unaligned_ok && offset >= 0) || (!unaligned_ok && offset >= 0 && offset + ip_align >= 0 && - offset + ip_align % size == 0))) { + (offset + ip_align) % size == 0))) { bool ldx_off_ok = offset <= S16_MAX; *insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_H); -- 2.53.0