From nobody Mon Jun 8 08:28:03 2026 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (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 A6DA22D592D for ; Thu, 4 Jun 2026 15:05:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.174 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585544; cv=none; b=W5HrIT1YBLuJWzkDuNL4YYKUahXRtTzMcPXlCktwsU1bZ4snTBmK8YD/5ll2ddAnAVjBSCXNIZuAzOTeG/RvPzonT60bFkdGi3f36O1OsOVpmDZlqPQaTVyfsWoYu1JfIIdHzdMP+KmF3lWy490UhaSdzWgrNdDfLO/K8GnJ7xg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585544; c=relaxed/simple; bh=cOu2Zf/scBr0msyOIEfMjOqnF2tQW/6bFHLnESgrAwc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ij3xoHqI5WCpeI2XZEJVaxC2h9lOtOwnUFtnhjn7ao+NAfh7ndi8CYzsFgJGIc9MTRCrgiSkafCdKO5ocbnjxCdwqfARl3gc5z74xbKMvA81c/SqW4wXYdDHpjllUMgpepVvDWVR41JsihJ7tjqPvdWiuIBFspbGbibehaGHb3I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Qjyu+Qlc; arc=none smtp.client-ip=91.218.175.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Qjyu+Qlc" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1780585539; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Rz2F6zrsu2suhD7OyTfzNyj4hxYQQ9GfxAsxAAQXUkM=; b=Qjyu+QlcjNXdoYeRZ/fdbsRQF2dtRo2AFvkQHJ0S0kvZxb4w5m/XGAVkjM8eIRsLSRn3i2 6BkHQoUG2HXJg0jzaggTJYEfKlKi1CIWTYye3U6jRMdkPTWSR+9Gzasm7ARw1PdWt6uHFQ xkkxXsycuJXbs0YipC/gMFt9hQlZz1k= From: Leon Hwang To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , Shuah Khan , Yuyang Huang , Leon Hwang , KP Singh , Dave Marchevsky , Stanislav Fomichev , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-patches-bot@fb.com, Mykyta Yatsenko Subject: [PATCH bpf-next v2 1/3] bpf: Check tail zero of bpf_map_info Date: Thu, 4 Jun 2026 23:05:03 +0800 Message-ID: <20260604150505.99129-2-leon.hwang@linux.dev> In-Reply-To: <20260604150505.99129-1-leon.hwang@linux.dev> References: <20260604150505.99129-1-leon.hwang@linux.dev> 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-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" Since there're 4 bytes padding at the end of struct bpf_map_info, they won't be checked by bpf_check_uarg_tail_zero(). pahole -C bpf_map_info ./vmlinux struct bpf_map_info { ... __u64 hash __attribute__((__aligned__(8))); /* 88 = 8 */ __u32 hash_size; /* 96 4 */ /* size: 104, cachelines: 2, members: 18 */ /* padding: 4 */ /* forced alignments: 1 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); If a future kernel extension adds a new 4-byte field, older userspace programs allocating this structure on the stack might inadvertently pass uninitialized stack garbage into the new field, permanently breaking backward compatibility. -- sashiko [1] Fix it by changing sizeof(info) to offsetofend(struct bpf_map_info, hash_size). [1] https://lore.kernel.org/bpf/20260513224823.6494FC19425@smtp.kernel.org/ Fixes: ea2e6467ac36 ("bpf: Return hashes of maps in BPF_OBJ_GET_INFO_BY_FD") Acked-by: Mykyta Yatsenko Signed-off-by: Leon Hwang --- kernel/bpf/syscall.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 625a4366fe6d..1007fb7c87e9 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5400,10 +5400,11 @@ static int bpf_map_get_info_by_fd(struct file *file, { struct bpf_map_info __user *uinfo =3D u64_to_user_ptr(attr->info.info); struct bpf_map_info info; - u32 info_len =3D attr->info.info_len; + u32 info_len =3D attr->info.info_len, len; int err; =20 - err =3D bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_l= en); + len =3D offsetofend(struct bpf_map_info, hash_size); + err =3D bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), len, info_len); if (err) return err; info_len =3D min_t(u32, sizeof(info), info_len); --=20 2.54.0 From nobody Mon Jun 8 08:28:03 2026 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (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 38DD63101A6 for ; Thu, 4 Jun 2026 15:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585554; cv=none; b=mLc5LWgHPKwDQgutFgGZbqdoFuiEINWIrXWPaxe1tKj8TNEiE7a7rBNTAaFJQ/qBNUkkDdT3Y0ADIg8BecNu1+JvKx3zwQ4Zwd+ATVacVA45cAmrBEZuHAhrPrMkvNgdo3t1TCiGRUgwcjuVEz3yE0ncynwnZ/80nqwT9HvNEHM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585554; c=relaxed/simple; bh=wlQ5x8dSF1J8/MWUD61qF9vPDOGbwB90oG5UbESi4eU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TCnifJBPsR08aJyG/rK6UXAiFyq7LEtkpEkX+dSpYAAeKocJHJZsNI8J6S8lQui7Qgfu986CYs0DGzWgvLpMQHnLPq2mIK7iGwGX6giHlrKIJJCSeOaoL4peMAlnuT+3Z/s8PcPUKZ0kEHP2SNaU1+TUBErDLfF+MW17kdYZtnc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=qkIGHWuL; arc=none smtp.client-ip=91.218.175.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="qkIGHWuL" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1780585548; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JcExdXGWFg882mqgHkmP35ZC5fLdpc+f8+br0xZGCsI=; b=qkIGHWuL2lNixjZMb8gNJpLuN1IgJ1EypHMce5HaQ6Bw3viYER+UYszWnrLE0jI6PakzNw FS+bAg4AlZTZJ5ee1UU5/EXsM1LvtEBJOlaxcUvpXjYM1h+2OCNLkEts1qccdi6zvWKaWV nn+9zdEQff/DbppHbBpAcVpnbkfewrs= From: Leon Hwang To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , Shuah Khan , Yuyang Huang , Leon Hwang , KP Singh , Dave Marchevsky , Stanislav Fomichev , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-patches-bot@fb.com, Mykyta Yatsenko Subject: [PATCH bpf-next v2 2/3] bpf: Check tail zero of bpf_prog_info Date: Thu, 4 Jun 2026 23:05:04 +0800 Message-ID: <20260604150505.99129-3-leon.hwang@linux.dev> In-Reply-To: <20260604150505.99129-1-leon.hwang@linux.dev> References: <20260604150505.99129-1-leon.hwang@linux.dev> 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-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" Since there're 4 bytes padding at the end of struct bpf_prog_info, they won't be checked by bpf_check_uarg_tail_zero(). pahole -C bpf_prog_info ./vmlinux struct bpf_prog_info { ... __u32 attach_btf_obj_id; /* 220 4 */ __u32 attach_btf_id; /* 224 4 */ /* size: 232, cachelines: 4, members: 38 */ /* sum members: 224 */ /* sum bitfield members: 1 bits, bit holes: 1, sum bit holes: 31 bits */ /* padding: 4 */ /* forced alignments: 9 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); If a future kernel extension adds a new 4-byte field, older userspace programs allocating this structure on the stack might inadvertently pass uninitialized stack garbage into the new field, permanently breaking backward compatibility. -- sashiko [1] Fix it by changing sizeof(info) to offsetofend(struct bpf_prog_info, attach_btf_id). [1] https://lore.kernel.org/bpf/20260513224823.6494FC19425@smtp.kernel.org/ Fixes: aba64c7da983 ("bpf: Add verified_insns to bpf_prog_info and fdinfo") Acked-by: Mykyta Yatsenko Signed-off-by: Leon Hwang --- kernel/bpf/syscall.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 1007fb7c87e9..0c86a70d31c1 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5115,10 +5115,11 @@ static int bpf_prog_get_info_by_fd(struct file *fil= e, u32 info_len =3D attr->info.info_len; struct bpf_prog_kstats stats; char __user *uinsns; - u32 ulen; + u32 ulen, len; int err; =20 - err =3D bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_l= en); + len =3D offsetofend(struct bpf_prog_info, attach_btf_id); + err =3D bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), len, info_len); if (err) return err; info_len =3D min_t(u32, sizeof(info), info_len); --=20 2.54.0 From nobody Mon Jun 8 08:28:03 2026 Received: from out-173.mta0.migadu.com (out-173.mta0.migadu.com [91.218.175.173]) (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 5F9DF3233E8 for ; Thu, 4 Jun 2026 15:05:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585560; cv=none; b=qf+hozkKDIJJGRVgz8F01gOnBDZ8m1UxMUCu1D9NGhzGsZj4/UdHsVToPvNDxefmBLradMtZ6ryQ3DcMPiUxz5hQqB49CxZNyln2Z3bxflKD0xF1zWppOqQa9YRIKSMZPnQFEcULesqaNz1Xivf1KN0V9Dbp9GlYbUAdZpcZNZg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585560; c=relaxed/simple; bh=EgYgMVfqv6njLLBjyrAbnScrviM62jNC88o3hzWGWuE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f5BnDUcZXr0A1P38QbgqswKE8kdPg4tH9YOUPmUyzYdNKrA5RRERFHeXm9vrb4J5CB3Orjw1bakK+CetCfwfDwLpGJF7V3FKx25tit9/7I0Iwo7G//jMSQrGd89UHbvDOUZwF9mlkXeU7qvHsLB1DX34Smy5nNBVHlFYmrFMpM0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=j5B0PCUc; arc=none smtp.client-ip=91.218.175.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="j5B0PCUc" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1780585556; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N4OrGRrkkmGvIx1F20YwZyuqT7Zri8Jmo/WTZI/HFMg=; b=j5B0PCUc51zvZUfyt9pimoMunkMfXhd+Z+6qD07yWr9N2h52l7L4/tPyQvlqNCiSimcziN acFd0/0/znbRmT8lkvc9N+ppC/F3Yu1XpPZpVT0OrPvD7LBjLMy9RXVYjC4IOas1QW1sUM h+hhnm+f+JnHWIqClwtx/yFJlGm3920= From: Leon Hwang To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , Shuah Khan , Yuyang Huang , Leon Hwang , KP Singh , Dave Marchevsky , Stanislav Fomichev , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-patches-bot@fb.com Subject: [PATCH bpf-next v2 3/3] selftests/bpf: Add tests to verify checking padding bytes for bpf_[map,prog]_info Date: Thu, 4 Jun 2026 23:05:05 +0800 Message-ID: <20260604150505.99129-4-leon.hwang@linux.dev> In-Reply-To: <20260604150505.99129-1-leon.hwang@linux.dev> References: <20260604150505.99129-1-leon.hwang@linux.dev> 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-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" Add two tests to verify that the tail padding 4 bytes of struct bpf_map_info and bpf_prog_info are checked in syscall.c using bpf_check_uarg_tail_zero(). Signed-off-by: Leon Hwang --- .../selftests/bpf/prog_tests/bpf_attr_size.c | 55 +++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_attr_size.c b/tools= /testing/selftests/bpf/prog_tests/bpf_attr_size.c index 32159dc64da8..87842c4347a6 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_attr_size.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_attr_size.c @@ -62,8 +62,63 @@ static void test_query_size_boundaries(void) cgroup_skb_direct_packet_access__destroy(skel); } =20 +static void test_map_info_tail_zero(void) +{ + LIBBPF_OPTS(bpf_map_create_opts, map_opts); + struct bpf_map_info_fake { + __u8 info[offsetofend(struct bpf_map_info, hash_size)]; + __u32 pad; + } info =3D { + .pad =3D 1, + }; + int map_fd, err; + __u32 info_len; + + map_fd =3D bpf_map_create(BPF_MAP_TYPE_ARRAY, "arr", sizeof(int), 1, 1, &= map_opts); + if (!ASSERT_GE(map_fd, 0, "bpf_map_create")) + return; + + info_len =3D sizeof(info); + err =3D bpf_obj_get_info_by_fd(map_fd, &info, &info_len); + ASSERT_EQ(err, -E2BIG, "bpf_obj_get_info_by_fd"); + + close(map_fd); +} + +static void test_prog_info_tail_zero(void) +{ + LIBBPF_OPTS(bpf_prog_load_opts, prog_opts); + struct bpf_insn insns[] =3D { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + struct bpf_prog_info_fake { + __u8 info[offsetofend(struct bpf_prog_info, attach_btf_id)]; + __u32 pad; + } info =3D { + .pad =3D 1, + }; + int prog_fd, err; + __u32 info_len; + + prog_fd =3D bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "test_prog", "GPL"= , insns, + ARRAY_SIZE(insns), &prog_opts); + if (!ASSERT_GE(prog_fd, 0, "bpf_prog_load")) + return; + + info_len =3D sizeof(info); + err =3D bpf_obj_get_info_by_fd(prog_fd, &info, &info_len); + ASSERT_EQ(err, -E2BIG, "bpf_obj_get_info_by_fd"); + + close(prog_fd); +} + void test_bpf_attr_size(void) { if (test__start_subtest("query_size_boundaries")) test_query_size_boundaries(); + if (test__start_subtest("map_info_tail_zero")) + test_map_info_tail_zero(); + if (test__start_subtest("prog_info_tail_zero")) + test_prog_info_tail_zero(); } --=20 2.54.0