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 688A839A7FE; Sat, 30 May 2026 18:41:01 +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=1780166462; cv=none; b=nMKfp7BK1zzraNcNwKN0IJ4yiVQJ8TBYEMQGIjEEkRUhiUlCyPSjUGRR+2cNYc4a2GHn4n6y5BntCcmJUutIGytJoMNCvat2mI5ZOJ3+yowlDt6HQBFtVndaAO964hXDhipX2G0J8oyrBRxRSlI4YhkHn2Y/aM2FBD5DGOf3w2Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780166462; c=relaxed/simple; bh=1i53uHVP/MHVz35horkNTyi6Uvr+h2fBSdZnk0/H+u8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k//s8GFhAMCokEXgoBa74vkZY6qJDbzgGlAPwssk+CkQo8oEfc/q+PTh8zZVDrq3yvLSiYMBIz28G209twAJtDNm9nBOz4g9X+BYa6RWyjd6m1UI2kooImEnfyryO1wNez8XuV2DSjnUIL3vFjbyqra/NXSSSgHKHvds62Tsmus= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BSDRRGJl; 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="BSDRRGJl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A87DB1F00893; Sat, 30 May 2026 18:41:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780166461; bh=5uFzvdOXJfGc0YxH1RltStvmry72pqHYrpgV/AjCxtU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BSDRRGJl3GQkTaIdSDquGldOMm5/KvrrfA0brInRa2G2VzJIS97yB1K63QCs9Ldp0 9gV0oeWV/aT9MfCMiw0ZMF0ornywuI8MyAYuUGcLLqGuivESn6xUnNxSIvDXry4Tee FX5FLNrHnfRZx5uTXXjnYZB8mpgzogIId257lVJI= 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 5.10 380/589] bpf: Fix precedence bug in convert_bpf_ld_abs alignment check Date: Sat, 30 May 2026 18:04:21 +0200 Message-ID: <20260530160234.788688564@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160224.570625122@linuxfoundation.org> References: <20260530160224.570625122@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 5.10-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 7002368d1592a..b8d891f79b983 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -489,7 +489,7 @@ 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