From nobody Tue Dec 16 14:52:41 2025 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AAF3A3278E2 for ; Mon, 5 May 2025 22:34:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746484487; cv=none; b=P1WjI9uI8HTS0ipERhAZuuBm8NSZNNymS6Yx2Iitv6blsFSjZTBsl7IMXZYzaB/vmbJAOrgD+0UOaTu2qrkwBfzHuTjtuCVeGkr3MIE05DOf+dU7gyMYSr98GAV1WNJEnHrFYuMg/sRr7ssMhe7s1Ht6IXF5fn8BQDOoptJE3lg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746484487; c=relaxed/simple; bh=XrFF3q8OIdWbIbgL5KEcKR7w3M0aeaM2dGRoWCTQ0Bo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=EQyveE4P1IKWz1zkQgP9HfK16947omzmlPdF7HneKtEMxlYEGfutlvgMMiHkU5wvHblxBzLK+vVT5hSVevt7IYTeNHEmBZqTEvuhfMojjc0GF/40kv2GzF5TiEBXv84xYQj8RhpfgVdhJHG2q7aglrc9gSpFAUzUVXrZtn4fQis= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--samitolvanen.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=BOEDVx7a; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--samitolvanen.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="BOEDVx7a" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-afd1e7f52f7so2602240a12.1 for ; Mon, 05 May 2025 15:34:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1746484485; x=1747089285; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=7UG6GYoDYUvSTCJXNbhcTCy+rTclDma5rPa6bv6GcMw=; b=BOEDVx7afTopZwemKnnNK77BZmTnv4adxC7u0Bwj3DRFVvziBcuuywB/DTryIUWQMe 5nS6r9wcCL1aD61rrj5N8nkbDje/zpR2NOYoq0fYbErxuRgxZ4Ck6Dh998PaqyC8DHUh 1Z2akJ0yj1cGXwdm4LHjzss2dQ15xKis50tiTmfmszSbr05QsEQ+CFaO+j3IR0Wpzvil 5HBaKcAD9RVgc0+EDkWs7Bf65ezknRiTbhEJAuVXFHLI6mHalCwj93w7rdGtdZfXyjS6 b3JdeYSnceZxul9Xy0hKAvTR3zBDoM4YJhztKaq3xS3INsYxSKzxdtw5WaaSCsNJb1Yr JdzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1746484485; x=1747089285; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7UG6GYoDYUvSTCJXNbhcTCy+rTclDma5rPa6bv6GcMw=; b=My8YNbibEZz7/eAfTOQdP8RA7wSQmsUHlU1IHwwWknqAZC9CkZ3AfFkLTz3LQM4XBt qLTyiu9aY43rmDc9XWFTnccbQzXVtMRJx5FBEdncmLScFUof8XnX1ao9GQcR941DlQ9N E+4mxU2UtHNQEvUYm9kUviV7j2MLmjONv7TEnmlA4IxxoIbBytrfM1HfVGi/0YR+hHGp zoHoE3r7ga2pqWoZHaAvqlKubqu5l22Sh+Cq4vDd46xRqLGx+qbMO43Emky/CQSIPVDk QKRjl5SAP2IyNmhQcm5ey7F1n+B2cO1HX5Y1LXD0RO3dVYcCUq69FNN//WYp5IXkWjm/ m/Ag== X-Forwarded-Encrypted: i=1; AJvYcCXA4/VuxSVnCevKDuxFEDOmUtvSUgw3068ruD0PoPii/LzpzQamOLzwc/svbB4YTK4qWt0aIaaRlGXHjgw=@vger.kernel.org X-Gm-Message-State: AOJu0Yw1ZqDCEvh3PUinAQsmUFiHfri5AcPXB6Kyg6md1B4p+oCS/6zJ yrybnurWYwbVilTc8R0I4noWXd1FTH64S5WFQKNY/4Gi/5bghLgGANNm0STSFfGx0r19F5EK4So zPgKRXnLEtt97yvIuoo0h41pTlw== X-Google-Smtp-Source: AGHT+IG9/bqquqZo0+5ekAmT9vTMi2AWIW4fPAq3lK8wl6/RiTTEb6BBW0o8BycH8+xREXoGfTl4Z8+v6d38vWKGCxA= X-Received: from pgar26.prod.google.com ([2002:a05:6a02:2e9a:b0:af0:e359:c50a]) (user=samitolvanen job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:43a3:b0:1f5:6c7b:8920 with SMTP id adf61e73a8af0-2118076ae4dmr1028201637.9.1746484484997; Mon, 05 May 2025 15:34:44 -0700 (PDT) Date: Mon, 5 May 2025 22:34:40 +0000 In-Reply-To: <20250505223437.3722164-4-samitolvanen@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250505223437.3722164-4-samitolvanen@google.com> X-Developer-Key: i=samitolvanen@google.com; a=openpgp; fpr=35CCFB63B283D6D3AEB783944CB5F6848BBC56EE X-Developer-Signature: v=1; a=openpgp-sha256; l=5846; i=samitolvanen@google.com; h=from:subject; bh=7DbjnHH5VAkImXf9y6kWO2Cpd7OKLAKDbR8A6OUcpSo=; b=owGbwMvMwCEWxa662nLh8irG02pJDBmSNv+n70wW3Td999qDnluU1h/qaZRrv6XgbvBB9fe9j n2HrxUxdJSyMIhxMMiKKbK0fF29dfd3p9RXn4skYOawMoEMYeDiFICJ3PVg+Kcseq1CSHzW1a6c rZ4n9e4dPmdvfbpob7XIB/7NkjLOEkcZGdbeDuLtcTvWJBP+IZHFKOjdccWdfaFpL+7dCbLplng aygEA X-Mailer: git-send-email 2.49.0.967.g6a0df3ecc3-goog Message-ID: <20250505223437.3722164-6-samitolvanen@google.com> Subject: [PATCH bpf-next v9 2/2] arm64/cfi,bpf: Support kCFI + BPF on arm64 From: Sami Tolvanen To: bpf@vger.kernel.org, Puranjay Mohan , Alexei Starovoitov , Daniel Borkmann Cc: Catalin Marinas , Will Deacon , Andrii Nakryiko , Mark Rutland , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Maxwell Bland , Puranjay Mohan , Sami Tolvanen , Dao Huang Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Puranjay Mohan Currently, bpf_dispatcher_*_func() is marked with `__nocfi` therefore calling BPF programs from this interface doesn't cause CFI warnings. When BPF programs are called directly from C: from BPF helpers or struct_ops, CFI warnings are generated. Implement proper CFI prologues for the BPF programs and callbacks and drop __nocfi for arm64. Fix the trampoline generation code to emit kCFI prologue when a struct_ops trampoline is being prepared. Signed-off-by: Puranjay Mohan Co-developed-by: Maxwell Bland Signed-off-by: Maxwell Bland Co-developed-by: Sami Tolvanen Signed-off-by: Sami Tolvanen Tested-by: Dao Huang --- arch/arm64/include/asm/cfi.h | 23 +++++++++++++++++++++++ arch/arm64/kernel/alternative.c | 25 +++++++++++++++++++++++++ arch/arm64/net/bpf_jit_comp.c | 22 +++++++++++++++++++--- 3 files changed, 67 insertions(+), 3 deletions(-) create mode 100644 arch/arm64/include/asm/cfi.h diff --git a/arch/arm64/include/asm/cfi.h b/arch/arm64/include/asm/cfi.h new file mode 100644 index 000000000000..670e191f8628 --- /dev/null +++ b/arch/arm64/include/asm/cfi.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_ARM64_CFI_H +#define _ASM_ARM64_CFI_H + +#ifdef CONFIG_CFI_CLANG +#define __bpfcall +static inline int cfi_get_offset(void) +{ + return 4; +} +#define cfi_get_offset cfi_get_offset +extern u32 cfi_bpf_hash; +extern u32 cfi_bpf_subprog_hash; +extern u32 cfi_get_func_hash(void *func); +#else +#define cfi_bpf_hash 0U +#define cfi_bpf_subprog_hash 0U +static inline u32 cfi_get_func_hash(void *func) +{ + return 0; +} +#endif /* CONFIG_CFI_CLANG */ +#endif /* _ASM_ARM64_CFI_H */ diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternativ= e.c index 8ff6610af496..71c153488dad 100644 --- a/arch/arm64/kernel/alternative.c +++ b/arch/arm64/kernel/alternative.c @@ -8,11 +8,13 @@ =20 #define pr_fmt(fmt) "alternatives: " fmt =20 +#include #include #include #include #include #include +#include #include #include #include @@ -298,3 +300,26 @@ noinstr void alt_cb_patch_nops(struct alt_instr *alt, = __le32 *origptr, updptr[i] =3D cpu_to_le32(aarch64_insn_gen_nop()); } EXPORT_SYMBOL(alt_cb_patch_nops); + +#ifdef CONFIG_CFI_CLANG +struct bpf_insn; + +/* Must match bpf_func_t / DEFINE_BPF_PROG_RUN() */ +extern unsigned int __bpf_prog_runX(const void *ctx, + const struct bpf_insn *insn); +DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX); + +/* Must match bpf_callback_t */ +extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64); +DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn); + +u32 cfi_get_func_hash(void *func) +{ + u32 hash; + + if (get_kernel_nofault(hash, func - cfi_get_offset())) + return 0; + + return hash; +} +#endif /* CONFIG_CFI_CLANG */ diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 70d7c89d3ac9..3b3691e88dd5 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -9,6 +9,7 @@ =20 #include #include +#include #include #include #include @@ -164,6 +165,12 @@ static inline void emit_bti(u32 insn, struct jit_ctx *= ctx) emit(insn, ctx); } =20 +static inline void emit_kcfi(u32 hash, struct jit_ctx *ctx) +{ + if (IS_ENABLED(CONFIG_CFI_CLANG)) + emit(hash, ctx); +} + /* * Kernel addresses in the vmalloc space use at most 48 bits, and the * remaining bits are guaranteed to be 0x1. So we can compose the address @@ -474,7 +481,6 @@ static int build_prologue(struct jit_ctx *ctx, bool ebp= f_from_cbpf) const bool is_main_prog =3D !bpf_is_subprog(prog); const u8 fp =3D bpf2a64[BPF_REG_FP]; const u8 arena_vm_base =3D bpf2a64[ARENA_VM_START]; - const int idx0 =3D ctx->idx; int cur_offset; =20 /* @@ -500,6 +506,9 @@ static int build_prologue(struct jit_ctx *ctx, bool ebp= f_from_cbpf) * */ =20 + emit_kcfi(is_main_prog ? cfi_bpf_hash : cfi_bpf_subprog_hash, ctx); + const int idx0 =3D ctx->idx; + /* bpf function may be invoked by 3 instruction types: * 1. bl, attached via freplace to bpf prog via short jump * 2. br, attached via freplace to bpf prog via long jump @@ -2009,9 +2018,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog = *prog) jit_data->ro_header =3D ro_header; } =20 - prog->bpf_func =3D (void *)ctx.ro_image; + prog->bpf_func =3D (void *)ctx.ro_image + cfi_get_offset(); prog->jited =3D 1; - prog->jited_len =3D prog_size; + prog->jited_len =3D prog_size - cfi_get_offset(); =20 if (!prog->is_func || extra_pass) { int i; @@ -2271,6 +2280,12 @@ static int prepare_trampoline(struct jit_ctx *ctx, s= truct bpf_tramp_image *im, /* return address locates above FP */ retaddr_off =3D stack_size + 8; =20 + if (flags & BPF_TRAMP_F_INDIRECT) { + /* + * Indirect call for bpf_struct_ops + */ + emit_kcfi(cfi_get_func_hash(func_addr), ctx); + } /* bpf trampoline may be invoked by 3 instruction types: * 1. bl, attached to bpf prog or kernel function via short jump * 2. br, attached to bpf prog or kernel function via long jump @@ -2790,6 +2805,7 @@ void bpf_jit_free(struct bpf_prog *prog) sizeof(jit_data->header->size)); kfree(jit_data); } + prog->bpf_func -=3D cfi_get_offset(); hdr =3D bpf_jit_binary_pack_hdr(prog); bpf_jit_binary_pack_free(hdr, NULL); WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog)); --=20 2.49.0.967.g6a0df3ecc3-goog