From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F06F6144D39; Sun, 24 Mar 2024 22:51:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711320688; cv=none; b=fR1oRe3T+aFs9Eaaxt9GfGx4SFRVeGtrk3VxPvKvdcfHtPSyWB4EpOJmy1cL9fJvZxaqukFFDZk70vK1c3s9ORkTTKZAbrql2c4yQvCYDGjWxlxVegn2RE260KdeCRyvVAGwAydNXWggt1yqHy3EyfvQhQRKrdWL6q4qJrx0P0s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711320688; c=relaxed/simple; bh=isTZTY2eL+mHyIWUYTdw55y79VDbuWALPvivaY3weT8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X0hRt/S9cAwIvT0/fqRS+YX0J4nkRM6kKNBKzh9Xxo2q7Hf5pUl9xw9O5iDZXtbI5vgVbZmrxwiqVI5xOxVmvu/Ml+dO03PxZp7IIle40eGiMraswKe7mRUL+sOpE8hL5/L1LZpSg0+LngdfBMfUqvNMndgz/w51o2ysii438ZI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Kn4yMWVZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Kn4yMWVZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37FF8C43390; Sun, 24 Mar 2024 22:51:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711320687; bh=isTZTY2eL+mHyIWUYTdw55y79VDbuWALPvivaY3weT8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kn4yMWVZaB1Idi1FDj520tWdKMZWqgnkqMTtWYRt+mI9R9fN8F+6KnoRY4d2/2QCN /OYg/fjNhmhedtFkRn1+JC3BgZYn4PSWcxQ6pPWgQqMBiCskZfzmP+9M2T5Wi0AY++ rCfgwF2y9bqE2vP6ajsaEouiDETwuoInYahkND8iuUGlQF5CaSThshEq2xBJlCMEVt Qb7UiUH+eONEpe/RtKnk5OiTKh4+J+1Of+sj4QPiD9blg7dIZgfm1VGRzZRrVlrMJ9 LWHBNDJr6ORVL8pv4jmyi75XU5qGUJhlm5lasxLdb36ty8aVs+a9YxDm/O9UjcibVU FWZVCbl7lXOHQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrii Nakryiko , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.7 250/713] bpf: don't infer PTR_TO_CTX for programs with unnamed context type Date: Sun, 24 Mar 2024 18:39:36 -0400 Message-ID: <20240324224720.1345309-251-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324224720.1345309-1-sashal@kernel.org> References: <20240324224720.1345309-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Andrii Nakryiko [ Upstream commit 879bbe7aa4afa80acf72a1cad7f52416ea78c52d ] For program types that don't have named context type name (e.g., BPF iterator programs or tracepoint programs), ctx_tname will be a non-NULL empty string. For such programs it shouldn't be possible to have PTR_TO_CTX argument for global subprogs based on type name alone. arg:ctx tag is the only way to have PTR_TO_CTX passed into global subprog for such program types. Fix this loophole, which currently would assume PTR_TO_CTX whenever user uses a pointer to anonymous struct as an argument to their global subprogs. This happens in practice with the following (quite common, in practice) approach: typedef struct { /* anonymous */ int x; } my_type_t; int my_subprog(my_type_t *arg) { ... } User's intent is to have PTR_TO_MEM argument for `arg`, but verifier will complain about expecting PTR_TO_CTX. This fix also closes unintended s390x-specific KPROBE handling of PTR_TO_CTX case. Selftest change is necessary to accommodate this. Fixes: 91cc1a99740e ("bpf: Annotate context types") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240212233221.2575350-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/btf.c | 3 +++ .../bpf/progs/test_global_func_ctx_args.c | 19 +++++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 15d71d2986d3a..a17da40f65d31 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5665,6 +5665,9 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n"); return NULL; } + /* program types without named context types work only with arg:ctx tag */ + if (ctx_tname[0] == '\0') + return false; /* only compare that prog's ctx type name is the same as * kernel expects. No need to compare field by field. * It's ok for bpf prog to do: diff --git a/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c b/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c index 7faa8eef0598b..144d30e654ad2 100644 --- a/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c +++ b/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c @@ -26,6 +26,23 @@ int kprobe_typedef_ctx(void *ctx) return kprobe_typedef_ctx_subprog(ctx); } +/* s390x defines: + * + * typedef user_pt_regs bpf_user_pt_regs_t; + * typedef struct { ... } user_pt_regs; + * + * And so "canonical" underlying struct type is anonymous. + * So on s390x only valid ways to have PTR_TO_CTX argument in global subprogs + * are: + * - bpf_user_pt_regs_t *ctx (typedef); + * - struct bpf_user_pt_regs_t *ctx (backwards compatible struct hack); + * - void *ctx __arg_ctx (arg:ctx tag) + * + * Other architectures also allow using underlying struct types (e.g., + * `struct pt_regs *ctx` for x86-64) + */ +#ifndef bpf_target_s390 + #define pt_regs_struct_t typeof(*(__PT_REGS_CAST((struct pt_regs *)NULL))) __weak int kprobe_struct_ctx_subprog(pt_regs_struct_t *ctx) @@ -40,6 +57,8 @@ int kprobe_resolved_ctx(void *ctx) return kprobe_struct_ctx_subprog(ctx); } +#endif + /* this is current hack to make this work on old kernels */ struct bpf_user_pt_regs_t {}; -- 2.43.0