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 5128E50254F; Wed, 30 Sep 2026 16:38:05 +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=1790786286; cv=none; b=gJBBw1jVoBCluWsRlth+Sl71JjD5cgTyn92cwgztuEB+8zLbxM2ZpBFlUi+rhRdcBdx6EZ4E4YfS+/6TvX72/jCuokbYM2cX1ELXnguTsfRsb6FKZWI5zmJ2g4adD9EgVK64D11SfpR1UqbxfpSG8oY1SYLzfPkAP9VU3hewJdI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790786286; c=relaxed/simple; bh=5iMLWOUSsvXXy2fpux1jdMFma2ixnPfcZgtK2ofndXc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MBWN5aNJitsbydJfnXW2ZUr9qFIvglntLSB/CpQuEbDmHruRDU+M4+ICn9N1NkkBwxAdelNkXT7M/4vnKqlahuF+yw6zO+ZDGX3rXfraYCT9lg8JBm4kQdBgCSizTFwLIlUUVRs219RQqPN70N13dOsCTKPZe7Yc/FcykyE3Jw0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=r+CzjCk6; 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="r+CzjCk6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B318D1F000FF; Wed, 30 Sep 2026 16:38:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790786285; bh=hO4YRhSbP0Kz7+1a5p/MZMcAd5tRnn4QYpq3JBCzD7k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=r+CzjCk6rpMH6zJx7VrgJvFAIkaav2gNfqiMnzIBha6QvqwkVSvOuAB2LYJu18brY gvz2UdshbNA02X0EgzyaoF/2EtjbD5yykMriHz4FYXutWx+rJOOVwVWxB1lYrpmx+Z lcO20XGTAcTkbPM9tZ+GSf+Eku8kvsPKpU0WAgb4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, co+adfca3e91be95776@bugs.sh, Alexei Starovoitov , Weiming Shi , Daniel Borkmann , Emil Tsalapatis , Sasha Levin Subject: [PATCH 6.1 808/982] bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL Date: Wed, 30 Sep 2026 17:25:44 +0200 Message-ID: <20260930152434.113579560@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152416.775402466@linuxfoundation.org> References: <20260930152416.775402466@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Weiming Shi [ Upstream commit e4a62833adff6ef0fe7c0b90393204fe3c26b5c5 ] An LWT_SEG6LOCAL program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter may reallocate skb->head, leaving the per-CPU SRH pointer dangling. Post-program SRH validation then writes through that pointer. Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier rejects this unsafe helper combination. Other LWT program types continue to expose the helper through lwt_out_func_proto(). Fixes: 004d4b274e2a ("ipv6: sr: Add seg6local action End.BPF") Reported-by: co+adfca3e91be95776@bugs.sh Suggested-by: Alexei Starovoitov Signed-off-by: Weiming Shi Signed-off-by: Daniel Borkmann Reviewed-by: Emil Tsalapatis Closes: https://lore.kernel.org/all/GCy0KRM2IcQGoJQTjJEU9D0maBxXzEDHuQpq@bugs.sh/ Link: https://lore.kernel.org/bpf/DL9COXZQXX4V.1FN45QO2Q77ZH@gmail.com/ Link: https://lore.kernel.org/bpf/20260909040807.3885815-2-bestswngs@gmail.com Signed-off-by: Sasha Levin --- net/core/filter.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/core/filter.c b/net/core/filter.c index fe6d963d340bf..bb86d9db3731d 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -8535,6 +8535,8 @@ static const struct bpf_func_proto * lwt_seg6local_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { + case BPF_FUNC_skb_pull_data: + return NULL; #if IS_ENABLED(CONFIG_IPV6_SEG6_BPF) case BPF_FUNC_lwt_seg6_store_bytes: return &bpf_lwt_seg6_store_bytes_proto; -- 2.53.0