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 E16F63FB05A; Wed, 20 May 2026 18:16:47 +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=1779301010; cv=none; b=FOmhgJc5tbD6Uix9z3QSwUzlWlDNsKS0TUYQHr1MmdpmqH1vq4WaeXJOG+nJUNYyQ6L9pHE/mBAgjTVuzFuFSYRXpJR6JlpQn97JwYWzx9CINJBCU1LbtLEitYFquIx+mubwdWkR086S38Kp1AIksPj0KsHi6nHAjJaJOGqPR4E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301010; c=relaxed/simple; bh=n0U1z1GIo2iGgj9tcTtSXtf8A5TZIcaYUpbE19CUQYI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Xz1lQidSK+5u7TqjgM1RhqqhKqr3fKOEbmfCJnBGAK+VuUT3EFcYBlfwFwqOpn/IEqXt2vKqbaZJxDbkjxDQ9k2WHK11v/GfY28MEe/s5JpZEedAboXnfboHJMImniiiLn0oSiIHVl7GWoXzOAb5/zzkcLsBxPDQlZojAhNprK4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KK0fQML0; 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="KK0fQML0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6327B1F000E9; Wed, 20 May 2026 18:16:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779301006; bh=TJ5OLgsKv68g8mPsQUgfhPvUO5l7CJ+aI3UrouNsUgY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KK0fQML0VuO+78fqJvMFcOGDnCXKDKvIEdevuJELLYR91iUr3emLzWRPgQAEI3EeT uA4hzD8wPoQTWIpeIiusuMTMnpCSU50QptVsNk345UMIMCbPjlCYft6Vzwsskp8hEJ UbQx6ri/8HddzLztJBHJJdHVyPNZDOLgTp7LmbFA= 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 6.12 350/666] bpf: Fix precedence bug in convert_bpf_ld_abs alignment check Date: Wed, 20 May 2026 18:19:21 +0200 Message-ID: <20260520162118.815569655@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162111.222830634@linuxfoundation.org> References: <20260520162111.222830634@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: 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 795e558155c6d..1d7467601a32c 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -499,7 +499,7 @@ 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