From nobody Sat Jul 25 22:03:05 2026 Received: from zg8tmtyylji0my4xnjeumjiw.icoremail.net (zg8tmtyylji0my4xnjeumjiw.icoremail.net [162.243.161.220]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5F702343D7B; Mon, 13 Jul 2026 06:16:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.243.161.220 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783923413; cv=none; b=IXtPRvq+y6FzyfNRYtP0e1q6omENE5jxIkbvreJ+N7b7cjtiFQlsNAKl/NCNaMpL0OaSwlCG/EE3S3jF5Yc5Obhmon8pewZ/3VMafrE0JQHBNrY0icEVJlGw1Bg5QvAlUOY61k5FmTCLLBEx2bLCkUw5hFNRjACchQ6bfCu6i4s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783923413; c=relaxed/simple; bh=C3LYPw5QA2fUxSeoU3iHI4rpPZj6wddm2HRV+VJW4ng=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=swq2u9tdOgaNv5OwatUJ5ESDaT2Z+sorquaL0d4qwVovqm/JdvlY7SWShMiy998VCjzdln4GJex/+s5/raOGlq7bUjqNzN7dHXkoeVlYATk3FRPG5nUNcNBwO9XsMj8xF7yVrAB/eynjmnYMuJkkZotDutDjMrVbKDezrxip20A= 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=rdPPPTYp; arc=none smtp.client-ip=162.243.161.220 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="rdPPPTYp" 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=v3vyzA5KROyFR4WnfFCz7eppTlP+IGzMFY 3rNtAafig=; b=rdPPPTYpWPsh1BfWx4C/KoUJAE3zz/WZmW8E4ueYRcevwTVkei ay0cm2mUHVchbLGTfYMhmpSzoF1I/srb8vgufsTwpzXYIZLFhS9/aAdPvsF//lwY ocR6tX6Pkqx8ga2P/DgbqxXuHZUTrj1nBywwXQZramntgnhV76gm33NmA= Received: from c9a6c405b3f2.. (unknown [202.112.238.121]) by web3 (Coremail) with SMTP id ygQGZQBXpJGwglRqEFAjAw--.21425S3; Mon, 13 Jul 2026 14:16:44 +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 , Emil Tsalapatis , Shuah Khan , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next 1/2] bpf: Check byte type when validating helper stack reads Date: Mon, 13 Jul 2026 06:16:11 +0000 Message-Id: <855140e07cebafa6770d577ed107b2541b92f95e.1783920884.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: ygQGZQBXpJGwglRqEFAjAw--.21425S3 X-Coremail-Antispam: 1UD129KBjvdXoW7GrW3uw1xtryxWF4DWw1fXrb_yoWktrX_Ja 1Fv3Wkur4FvF4xA3ZrAa1fXw1xAr48GF4fZw18XryYqrWrZFn8ur93Wry7CFyDGrs5KrWD ZFsI93s0qr1S9jkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbHAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGwA2048vs2IY02 0Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84 ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1lnxkE FVAIw20F6cxK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I 8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jrv_JF1lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCF s4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFI xGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI0_Jw0_GFylc2xSY4AK67AK6r47MxAI w28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr 4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxG rwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJw CI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2 z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUU5Ef7UUUUU== X-CM-SenderInfo: xfkh05r1stqzpdlo2hxwvl0wxkxdhvlgxou0/ Content-Type: text/plain; charset="utf-8" check_stack_range_initialized() validates helper ranges byte by byte, but bpf_is_spilled_reg() only checks the slot-wide spill marker. For a CAP_BPF load, a narrow scalar spill marks only the covered bytes as STACK_SPILL. An untouched sibling remains STACK_INVALID, but the helper still accepts the read when the slot contains a spilled scalar. Require the byte being checked to be STACK_SPILL before accepting the slot-wide scalar spill state. Fixes: 354e8f1970f8 ("bpf: Support <8-byte scalar spill and refill") Signed-off-by: Yiyang Chen --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 03e2202cca13d..c971cf34c760b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6785,7 +6785,8 @@ static int check_stack_range_initialized( goto mark; } =20 - if (bpf_is_spilled_reg(&state->stack[spi]) && + if (*stype =3D=3D STACK_SPILL && + bpf_is_spilled_reg(&state->stack[spi]) && (state->stack[spi].spilled_ptr.type =3D=3D SCALAR_VALUE || env->allow_ptr_leaks)) { if (clobber) { --=20 2.34.1 From nobody Sat Jul 25 22:03:05 2026 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [4.193.249.245]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 141F33655FD; Mon, 13 Jul 2026 06:16:59 +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=1783923424; cv=none; b=hccus6T51hyk7czccsmnr16TaBNGTDc22+sFeWVE5lJxbO7WSMvWlVFjL4iyMXzVEnl7KbEgTUXM+30YGQf5eDKI2uYVtnkPrGK1mn5FF58vt8fXffNaCJDEHV17PHKOVCE8aXQyCeOv48c02wJQXL1sPixHEQ4CbUp1c/DZ1ok= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783923424; c=relaxed/simple; bh=JiKuvEK5TwKlotTplfcewv4m2HSMkRixEVxEm5janGw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=J/llzq6x3i/3lVM+qTLlU0KDzO9P1hbmaeo1Ok5iBu/sBJKLaYpuRBH79Z5q9ivNhKRBb2tmpLKxtGhKrNTDaIclbcTtPsCWCHfJfLWjJyDI45ez73o5WKvUpyXHxmmw3kNJmVIIWfTOBZrNiyp8hp1+1U+EQuqyipT0XQO1MIY= 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=MFL7W4Fi; 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="MFL7W4Fi" 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=YlwYcQQTP50tWS/GKB6PAZ0J5qg1x8sJTR 1dOrjh0R0=; b=MFL7W4Fifk064Tl+crrBr2TWDGWMoTBGsEPr6f1iydGlAYB/Ph X6y3eYRklHSkjo4k/5cEd0IDMbrlA3ixrMnFfhA7cog5YMQ7p+yvTQiNau6NuUdy 58+b5D9/huqZ0DFwVoyGfeZlzIpFD5Ejc2E8eVPyJ3MXSIwzupR2/2X/8= Received: from c9a6c405b3f2.. (unknown [202.112.238.121]) by web3 (Coremail) with SMTP id ygQGZQBXpJGwglRqEFAjAw--.21425S4; Mon, 13 Jul 2026 14:16:45 +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 , Emil Tsalapatis , Shuah Khan , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next 2/2] selftests/bpf: Cover helper reads of invalid spill siblings Date: Mon, 13 Jul 2026 06:16:12 +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: ygQGZQBXpJGwglRqEFAjAw--.21425S4 X-Coremail-Antispam: 1UD129KBjvJXoW7Zw17ZF43ur4UZFyrKr1UGFg_yoW8uF13p3 4DKaya9348Gr1xua43AFW8AFyrJF4kurW5XFs3t3WUurWDJw12qr4Ika17Cr1YkF18Xw4r ZFyaqay8C3WUuFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQE14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UM2 8EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2vY z4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c 02F40Ex7xfMcIj6xIIjxv20xvE14v26r1Y6r17McIj6I8E87Iv67AKxVWUJVW8JwAm72CE 4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4 IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS14v26r1q6r43MxkIecxEwVAFwVW8AwCF 04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r 18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkGc2Ij64vI r41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr 1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvE x4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUaZXrUUUUU= X-CM-SenderInfo: xfkh05r1stqzpdlo2hxwvl0wxkxdhvlgxou0/ Content-Type: text/plain; charset="utf-8" Add a verifier_spill_fill case that passes an untouched byte next to a one-byte scalar spill to bpf_map_update_elem(). The full-capability load retains the existing uninitialized-stack behavior, while the CAP_BPF-only load must reject the STACK_INVALID helper read. Signed-off-by: Yiyang Chen --- .../selftests/bpf/progs/verifier_spill_fill.c | 33 +++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c b/tool= s/testing/selftests/bpf/progs/verifier_spill_fill.c index 8b166c42c4e0e..e686f6d8d5656 100644 --- a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c +++ b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c @@ -11,6 +11,13 @@ struct { __uint(max_entries, 4096); } map_ringbuf SEC(".maps"); =20 +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u8); +} map_partial_spill SEC(".maps"); + SEC("socket") __description("check valid spill/fill") __success __failure_unpriv __msg_unpriv("R0 leaks addr") @@ -1307,6 +1314,32 @@ __naked void stack_noperfmon_spill_32bit_onto_64bit_= slot(void) : __clobber_all); } =20 +SEC("socket") +__description("helper read must reject an invalid sibling of a narrow spil= l") +__success +__caps_unpriv(CAP_BPF) +__failure_unpriv __msg_unpriv("invalid read from stack R3 off -7+0 size 1") +__naked void helper_read_invalid_partial_spill_sibling(void) +{ + asm volatile ("r5 =3D 1;\n\t" + "*(u8 *)(r10 - 8) =3D r5;\n\t" + "r2 =3D 0;\n\t" + "*(u32 *)(r10 - 16) =3D r2;\n\t" + "r1 =3D %[map_partial_spill] ll;\n\t" + "r2 =3D r10;\n\t" + "r2 +=3D -16;\n\t" + "r3 =3D r10;\n\t" + "r3 +=3D -7;\n\t" + "r4 =3D 0;\n\t" + "call %[bpf_map_update_elem];\n\t" + "r0 =3D 0;\n\t" + "exit;\n\t" + : + : __imm(bpf_map_update_elem), + __imm_addr(map_partial_spill) + : __clobber_all); +} + /* * stacksafe(): check if 32-bit scalar spill in old state is considered * equivalent to STACK_MISC in cur state. --=20 2.34.1