From nobody Fri Jul 24 23:30:20 2026 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [4.193.249.245]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DDDE231715D; Wed, 22 Jul 2026 05:28:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=4.193.249.245 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784698099; cv=none; b=tnJl1cUPto5EaqPxH0h1kCXxuVh4lTNDBvPa7Cp5ibCcr2Bd17G+8RSR8ZdvWSACDr1sNhdH8ol8LHWG6wEORwXL5SU19jU/EB+lPDRvJUMeTjXernIkRPixGormQRPVajDCg5pVNrI3qLwo1MUiy9qiesIODBez4fK9ia+vMWs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784698099; c=relaxed/simple; bh=xGhxK7DdoYgEgPczWOg20FJ0P83ccyHQFsCVYJuxmgs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hiW4YD14KOft0RW41K9SfZgfNoqu5q4S/gMO4NSn46rXS7wTwpufo1qs1OAXwlYB/kUxLklrGW5EbK3vu29uaGY3QJxihbZpXsktB6blF2fCPG4v+9/a6hbnQIl/oHH3ZBtEMbH6deObyuLSPTYVc+CY+qc/8Nplk40oYy8+G5Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b=WZgPddpX; arc=none smtp.client-ip=4.193.249.245 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b="WZgPddpX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mails.tsinghua.edu.cn; s=dkim; h=Received:From:To:Cc:Subject: Date:Message-Id:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=QSpZaUMg805BhWsPOR9AdS3pqyeG1IUi6N G3nKZSDO0=; b=WZgPddpXHgCYp9d6yTQTSO3PTHsKL52ioL12udwzeSmgd5byjp +YiVhxpNsiGwuVrtrKIj6wzwMJpTsRn/0tPN8SWcof7wiOwrgt9i58F6nBhgCBdd 8S0IiccGxs8wBOzVFP0U99F0cXkUv8GHpfpeDM7j+VeqFaUg1nZ1DwRHU= Received: from c9a6c405b3f2.. (unknown [202.112.238.121]) by web3 (Coremail) with SMTP id ygQGZQCHWRjYVGBqhCwkAA--.51860S3; Wed, 22 Jul 2026 13:27:58 +0800 (CST) From: Yiyang Chen To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi Cc: Yiyang Chen , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Shuah Khan , Emil Tsalapatis , Ihor Solodrai , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v3 1/3] bpf: Preserve pointer state for commuted arithmetic Date: Wed, 22 Jul 2026 05:27:31 +0000 Message-Id: <004a83de52a36e9f3acd6c3fa2d0dfd0a013460d.1784696372.git.chenyy23@mails.tsinghua.edu.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: ygQGZQCHWRjYVGBqhCwkAA--.51860S3 X-Coremail-Antispam: 1UD129KBjvJXoWxZw43Zw4rKw4rJFyfWF1DAwb_yoW5Zry8pw s7W3s3tr4kG3y7uw17ZF4qyr90kw4vqw1xCrykA34xCFW7JFyYqFWxKFyay3ySkrWvk34I kw4j9343ua4xXFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUd0b7Iv0xC_Cr1lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUGwA2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVWxJr0_GcWl84ACjcxK6I8E87Iv 6xkF7I0E14v26rxl6s0DM2vYz4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEnc xIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E 87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c 0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS14v26r4a 6rW5MxkIecxEwVAFwVW8WwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8Jw C20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAF wI0_GFv_WrylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjx v20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2 jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0x ZFpf9x0p_fHUOUUUUU= X-CM-SenderInfo: xfkh05r1stqzpdlo2hxwvl0wxkxdhvlgxou0/ Content-Type: text/plain; charset="utf-8" When scalar +=3D pointer is handled in adjust_ptr_min_max_vals(), the destination register inherits the pointer state from the source pointer. Copying only selected fields is fragile because pointer provenance is tracked by several bpf_reg_state fields. Use verifier-env scratch storage to preserve the scalar operand while replacing the destination with the full pointer state. This preserves the frame number for PTR_TO_STACK registers and keeps parent identity fields consistent. Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Signed-off-by: Yiyang Chen Tested-by: Daniel Wade --- kernel/bpf/verifier.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 52be0a118cce0..085cbd5222737 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -13726,11 +13726,14 @@ static int adjust_ptr_min_max_vals(struct bpf_ver= ifier_env *env, s64 smin_val =3D reg_smin(off_reg), smax_val =3D reg_smax(off_reg); u64 umin_val =3D reg_umin(off_reg), umax_val =3D reg_umax(off_reg); struct bpf_sanitize_info info =3D {}; + const struct bpf_reg_state *orig_off_reg =3D off_reg; + bool ptr_is_dst_reg; u8 opcode =3D BPF_OP(insn->code); u32 dst =3D insn->dst_reg; int ret, bounds_ret; =20 dst_reg =3D ®s[dst]; + ptr_is_dst_reg =3D ptr_reg =3D=3D dst_reg; =20 if ((known && (smin_val !=3D smax_val || umin_val !=3D umax_val)) || smin_val > smax_val || umin_val > umax_val) { @@ -13796,11 +13799,15 @@ static int adjust_ptr_min_max_vals(struct bpf_ver= ifier_env *env, return -EACCES; } =20 - /* In case of 'scalar +=3D pointer', dst_reg inherits pointer type and id. - * The id may be overwritten later if we create a new variable offset. + /* For 'scalar +=3D pointer', dst_reg inherits the complete pointer + * register state. Individual fields may be adjusted later by pointer + * arithmetic. */ - dst_reg->type =3D ptr_reg->type; - dst_reg->id =3D ptr_reg->id; + if (!ptr_is_dst_reg) { + env->fake_reg[0] =3D *off_reg; + off_reg =3D &env->fake_reg[0]; + *dst_reg =3D *ptr_reg; + } =20 if (!check_reg_sane_offset_scalar(env, off_reg, ptr_reg->type) || !check_reg_sane_offset_ptr(env, ptr_reg, ptr_reg->type)) @@ -13813,7 +13820,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verif= ier_env *env, ret =3D sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg, &info, false); if (ret < 0) - return sanitize_err(env, insn, ret, off_reg, dst_reg); + return sanitize_err(env, insn, ret, orig_off_reg, dst_reg); } =20 switch (opcode) { @@ -13843,7 +13850,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verif= ier_env *env, } break; case BPF_SUB: - if (dst_reg =3D=3D off_reg) { + if (!ptr_is_dst_reg) { /* scalar -=3D pointer. Creates an unknown scalar */ verbose(env, "R%d tried to subtract pointer from scalar\n", dst); @@ -13906,7 +13913,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verif= ier_env *env, return -EFAULT; } if (ret < 0) - return sanitize_err(env, insn, ret, off_reg, dst_reg); + return sanitize_err(env, insn, ret, orig_off_reg, dst_reg); } =20 return 0; --=20 2.34.1 From nobody Fri Jul 24 23:30:20 2026 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [13.75.44.102]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B130A2EC09B; Wed, 22 Jul 2026 05:28:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.75.44.102 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784698096; cv=none; b=qUqIwAD9wNyAy5AgPjUaaCWrprHMu3vQ0OSfpSMeGaraeM0VXMzjppw77bxXrIyaISKg1kOUSn0ZncpRY4HEJ99KmaWXEPYm/q5HE/nO8d90LjCYyvxEfMYNopnZo1Pmf4wXyJUfoYbN6mG/WKudZWRe/M2NYxXG1B/BIaQgbRI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784698096; c=relaxed/simple; bh=2QdqK/6JOVi6skltdXH0fm1cc101NyyBzB7amGUEtpA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OGxBW26W5qZ6Fuf761iAe9DA2o4ft1MUkH7kBtv5OSBoqdVYEm15qiGJVeG2duZWEC54okwn/3j7nSjz/Hs62tOKuF66W8z3MVG2xyXK3c777Y8Dbv9KPjXiAZO6GQv2IG8GVmxOGrNxoKBA1I0iVQBBr9zNfzD/f+2mGWLvdzo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b=XS6TV5/C; arc=none smtp.client-ip=13.75.44.102 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b="XS6TV5/C" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mails.tsinghua.edu.cn; s=dkim; h=Received:From:To:Cc:Subject: Date:Message-Id:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=DZBLtyaloC6tsS8hH7wA7itFZIqQj/vsKR OJLJZXlQQ=; b=XS6TV5/CiUbTuaGBxVOjlS5O2gJRaq1Ry8dmYIqUfSU0OiSAxI a54AnzAZD3BHDJl7Opd3X9oem67sdfGwDYn8MV20KqwTIqUTa0VvN5lB6za4ZB9N WJ7uybg0BxoLcu995UiBGKPvYookHjKoT8dIRe1/FrhiC39rvxV0fG+e8= Received: from c9a6c405b3f2.. (unknown [202.112.238.121]) by web3 (Coremail) with SMTP id ygQGZQCHWRjYVGBqhCwkAA--.51860S4; Wed, 22 Jul 2026 13:28:00 +0800 (CST) From: Yiyang Chen To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi Cc: Yiyang Chen , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Shuah Khan , Emil Tsalapatis , Ihor Solodrai , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v3 2/3] bpf: Propagate untrusted pointer state in commuted arithmetic Date: Wed, 22 Jul 2026 05:27:32 +0000 Message-Id: <127ac07203a79eee325c0d3b8d912e2da7ab3c45.1784696372.git.chenyy23@mails.tsinghua.edu.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: ygQGZQCHWRjYVGBqhCwkAA--.51860S4 X-Coremail-Antispam: 1UD129KBjvJXoW7KF1UKw1kZFWxJw4kKrWktFb_yoW8WF1Upr WxGF9rtr48trW29asrZF4kAryrKan5t3yxCrWUZ34fCFn8XF4jgFWUKFyUZrZakFW0y34r tr1jv34Yg3W2vrDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUH014x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UM2 8EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAa c4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzV Aqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S 6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxw ACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVW8ZVWrXwCY02Avz4vE14v_GrWl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r 4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAI cVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7sRE_HUPUUUUU== X-CM-SenderInfo: xfkh05r1stqzpdlo2hxwvl0wxkxdhvlgxou0/ Content-Type: text/plain; charset="utf-8" The untrusted PTR_TO_MEM early return skips pointer offset tracking because accesses go through probe-read handling. Moving it after full pointer-state propagation ensures scalar +=3D untrusted_pointer leaves the destination as PTR_TO_MEM instead of an unrelated scalar. Fixes: f2362a57aeff ("bpf: allow void* cast using bpf_rdonly_cast()") Signed-off-by: Yiyang Chen Tested-by: Daniel Wade --- kernel/bpf/verifier.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 085cbd5222737..18fb6267692c5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -13763,13 +13763,6 @@ static int adjust_ptr_min_max_vals(struct bpf_veri= fier_env *env, return -EACCES; } =20 - /* - * Accesses to untrusted PTR_TO_MEM are done through probe - * instructions, hence no need to track offsets. - */ - if (base_type(ptr_reg->type) =3D=3D PTR_TO_MEM && (ptr_reg->type & PTR_UN= TRUSTED)) - return 0; - switch (base_type(ptr_reg->type)) { case PTR_TO_CTX: case PTR_TO_MAP_VALUE: @@ -13809,6 +13802,13 @@ static int adjust_ptr_min_max_vals(struct bpf_veri= fier_env *env, *dst_reg =3D *ptr_reg; } =20 + /* + * Accesses to untrusted PTR_TO_MEM are done through probe + * instructions, hence no need to track offsets. + */ + if (base_type(ptr_reg->type) =3D=3D PTR_TO_MEM && (ptr_reg->type & PTR_UN= TRUSTED)) + return 0; + if (!check_reg_sane_offset_scalar(env, off_reg, ptr_reg->type) || !check_reg_sane_offset_ptr(env, ptr_reg, ptr_reg->type)) return -EINVAL; --=20 2.34.1 From nobody Fri Jul 24 23:30:20 2026 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [4.193.249.245]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DDED7317163; Wed, 22 Jul 2026 05:28:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=4.193.249.245 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784698100; cv=none; b=GEzE6CKfbelT0Gav8MVIbwJyNjqFStSVaJyna4Hy0gyFuYOoKUdEtOY++LuQy/WrRDkrX4nxfgIHRWn2WIcOa8tkEhtIrfXRe5ZmcTwWqEZV63Z0TgqUKfA+iQceOpo8ftHp0DEKD1khSzL1pvL3kyD4pr/rjEbQE+DrlNVg6e4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784698100; c=relaxed/simple; bh=sJwUV4c68aV79UpjZxmUlGcUzwp8jye+tMF9s33rbw0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=rpMFal9KwJPgjuUSvvv31oZVbNIr4Sz7OuOuLYecLpQMCnMdwhjDvxQW4h8lnRraKfEkpPu0wrmAnPY/ulSCZMHlmfte2wA0AWjCzPqbkElNwBPvYrhKT97YgQvMwTe5YrfU3rit2JlTid5GDUXAzcoqmqcDYl16gsRaj3sm9Yw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b=IfY6r6NM; arc=none smtp.client-ip=4.193.249.245 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b="IfY6r6NM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mails.tsinghua.edu.cn; s=dkim; h=Received:From:To:Cc:Subject: Date:Message-Id:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=IYyKVj4+V1uChN5v0vRokVyhFYp0ttNjnZ /959qYKVs=; b=IfY6r6NMKdGbsE6O9vOsnLnUHXKUuHmW5fKOSE5hTgx68PYxio Xz0Hl1X2ps14eTZVQonVcS1o3Ttgdy29/4eEIl3/5CNYr8zh6tFy7H/5mZajCasn bepr92cJYcJcro89ZBhzypm+nppKzl06iepgnGStqFyuj47dXFKQcIpYU= Received: from c9a6c405b3f2.. (unknown [202.112.238.121]) by web3 (Coremail) with SMTP id ygQGZQCHWRjYVGBqhCwkAA--.51860S5; Wed, 22 Jul 2026 13:28:02 +0800 (CST) From: Yiyang Chen To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi Cc: Yiyang Chen , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Shuah Khan , Emil Tsalapatis , Ihor Solodrai , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v3 3/3] selftests/bpf: Cover commuted pointer state propagation Date: Wed, 22 Jul 2026 05:27:33 +0000 Message-Id: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: ygQGZQCHWRjYVGBqhCwkAA--.51860S5 X-Coremail-Antispam: 1UD129KBjvJXoWxuF4ruFW8Xr4furW5ur45KFg_yoWrGr1kpa ykua9aqr1IqF17Xa1xAFZ7XF45Cr4vqrWY9rWIyryUZF17Jr93Xr4xKFyjqrnxCrs8u390 vFyaqasxuF48X3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUH014x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UM2 8EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAa c4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzV Aqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S 6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxw ACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVW8ZVWrXwCY02Avz4vE14v_GrWl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r 4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAI cVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7sRi8ucPUUUUU== X-CM-SenderInfo: xfkh05r1stqzpdlo2hxwvl0wxkxdhvlgxou0/ Content-Type: text/plain; charset="utf-8" Add verifier coverage for the three cases affected by preserving the full pointer state across scalar +=3D pointer: stack frame number inheritance, readonly-untrusted memory access, and dynptr data-slice invalidation. Signed-off-by: Yiyang Chen Acked-by: Eduard Zingerman Tested-by: Daniel Wade --- .../testing/selftests/bpf/progs/dynptr_fail.c | 31 ++++++++++++++ .../bpf/progs/mem_rdonly_untrusted.c | 17 ++++++++ .../bpf/progs/verifier_basic_stack.c | 41 +++++++++++++++++++ 3 files changed, 89 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testin= g/selftests/bpf/progs/dynptr_fail.c index 94489ac64da8e..7da4266bae09b 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_fail.c +++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c @@ -1635,6 +1635,37 @@ static int callback(__u32 index, void *data) return 0; } =20 +/* A commuted add should preserve the parent id of a dynptr data slice. + */ +SEC("?raw_tp") +__failure __msg("invalid mem access 'scalar'") +int dynptr_slice_commuted_invalidate(void *ctx) +{ + struct bpf_dynptr ptr; + __u32 *slice, *derived; + + bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(__u32), 0, &ptr); + + slice =3D bpf_dynptr_data(&ptr, 0, sizeof(__u32)); + if (!slice) + goto done; + + asm volatile ("%[dst] =3D 0;" + "%[dst] +=3D %[src];" + "%[src] =3D 0;" + : [dst]"=3D&r"(derived), [src]"+r"(slice) + : + : "memory"); + + bpf_ringbuf_discard_dynptr(&ptr, 0); + val =3D *derived; + return 0; + +done: + bpf_ringbuf_discard_dynptr(&ptr, 0); + return 0; +} + /* If the dynptr is written into in a callback function, its data * slices should be invalidated as well. */ diff --git a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c b/too= ls/testing/selftests/bpf/progs/mem_rdonly_untrusted.c index 5b4453747c230..f166fff8f2176 100644 --- a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c +++ b/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c @@ -226,4 +226,21 @@ int null_check(void *ctx) return 0; } =20 +SEC("socket") +__success +__retval(1) +int ldx_is_ok_commuted_addr(void *ctx) +{ + int v, *p, *derived; + + v =3D 1; + p =3D bpf_rdonly_cast(&v, 0); + asm volatile ("%[dst] =3D 0;" + "%[dst] +=3D %[src];" + : [dst]"=3D&r"(derived) + : [src]"r"(p) + : "memory"); + return *derived; +} + char _license[] SEC("license") =3D "GPL"; diff --git a/tools/testing/selftests/bpf/progs/verifier_basic_stack.c b/too= ls/testing/selftests/bpf/progs/verifier_basic_stack.c index fb62e09f21146..d3df7a9f1d8c8 100644 --- a/tools/testing/selftests/bpf/progs/verifier_basic_stack.c +++ b/tools/testing/selftests/bpf/progs/verifier_basic_stack.c @@ -97,4 +97,45 @@ __naked void misaligned_read_from_stack(void) " ::: __clobber_all); } =20 +SEC("socket") +__description("stack pointer arithmetic preserves frame number") +__failure __msg("R7 invalid mem access 'scalar'") +__naked void stack_ptr_arith_preserves_frameno(void) +{ + asm volatile ("\ + r3 =3D 0; \ + *(u64 *)(r10 - 8) =3D r3; \ + r1 =3D %[map_hash_8b] ll; \ + r2 =3D r10; \ + r2 +=3D -8; \ + call %[bpf_map_lookup_elem]; \ + if r0 !=3D 0 goto +2; \ + r0 =3D 0; \ + exit; \ + r1 =3D r0; \ + r2 =3D 0; \ + r3 =3D 0; \ + call stack_ptr_arith_preserves_frameno_subprog;\ + r0 =3D 0; \ + exit; \ + ": + : __imm(bpf_map_lookup_elem), + __imm_addr(map_hash_8b) + : __clobber_all); +} + +static __used __naked void stack_ptr_arith_preserves_frameno_subprog(void) +{ + asm volatile ("\ + *(u64 *)(r10 - 8) =3D r1; \ + r6 =3D -8; \ + r6 +=3D r10; \ + *(u64 *)(r6 + 0) =3D r2; \ + r7 =3D *(u64 *)(r10 - 8); \ + *(u64 *)(r7 + 0) =3D r3; \ + r0 =3D 0; \ + exit; \ + "::: __clobber_all); +} + char _license[] SEC("license") =3D "GPL"; --=20 2.34.1