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 3FB461519AF; Wed, 5 Feb 2025 14:31:34 +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=1738765894; cv=none; b=G7DFMamsUzOK6NY6nd4NgM7UHRyTaWqNw/bOuAaEUUsVTl0YeF8STZ8GH71MEaTYxhkoJYFDk4Rf6/P43sN/1ntLNqsCD5LA339vsI12Y9SnROie/Rf2Gy0Kvfmo6xx+TDv9KGMKGQ11Rx1J20OGwoX02oO/1t7gbMhHaegylk4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738765894; c=relaxed/simple; bh=87FxbpYxF7EXFR2mUGpS0x6PdP1BKPxOzZnoAGn8nBI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nOnbK1rAZSsaYIj6G0gOHVsfbS/gRAQJlDXnEQurBDUTs5PCwucwRBrhK56XSEgfEaP6v+C+vUIdV9cwYq7RgpTHvJAlpAU2qwTN0czoiBmBSjUYid6WvGBumtXaO7qFwK7s3C9vwb9C5QR9DYkF8y4pTHiNEzuo8wvFgYCpl1Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tmcHjZn4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tmcHjZn4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A128EC4CED6; Wed, 5 Feb 2025 14:31:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738765894; bh=87FxbpYxF7EXFR2mUGpS0x6PdP1BKPxOzZnoAGn8nBI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tmcHjZn4G7DmhhzW5hDk8i/h0K9cJa0+8JHw+Gz5E8IfR8mJY8zcDtKpJhCx4ufle /0U/yn3yVMeqGraOHsxgrIxs2wcbAh2clHPD9Nmm6bnMr+xJ0uBCpbqynhTfkbTHaW sAMtXMHkCQdoSvccYz85n8+w95kHq8tpuhxTfWqc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Robert Morris , Martin KaFai Lau , Eduard Zingerman , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.12 265/590] bpf: Reject struct_ops registration that uses module ptr and the module btf_id is missing Date: Wed, 5 Feb 2025 14:40:20 +0100 Message-ID: <20250205134505.415062602@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250205134455.220373560@linuxfoundation.org> References: <20250205134455.220373560@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin KaFai Lau [ Upstream commit 96ea081ed52bf077cad6d00153b6fba68e510767 ] There is a UAF report in the bpf_struct_ops when CONFIG_MODULES=n. In particular, the report is on tcp_congestion_ops that has a "struct module *owner" member. For struct_ops that has a "struct module *owner" member, it can be extended either by the regular kernel module or by the bpf_struct_ops. bpf_try_module_get() will be used to do the refcounting and different refcount is done based on the owner pointer. When CONFIG_MODULES=n, the btf_id of the "struct module" is missing: WARN: resolve_btfids: unresolved symbol module Thus, the bpf_try_module_get() cannot do the correct refcounting. Not all subsystem's struct_ops requires the "struct module *owner" member. e.g. the recent sched_ext_ops. This patch is to disable bpf_struct_ops registration if the struct_ops has the "struct module *" member and the "struct module" btf_id is missing. The btf_type_is_fwd() helper is moved to the btf.h header file for this test. This has happened since the beginning of bpf_struct_ops which has gone through many changes. The Fixes tag is set to a recent commit that this patch can apply cleanly. Considering CONFIG_MODULES=n is not common and the age of the issue, targeting for bpf-next also. Fixes: 1611603537a4 ("bpf: Create argument information for nullable arguments.") Reported-by: Robert Morris Closes: https://lore.kernel.org/bpf/74665.1733669976@localhost/ Signed-off-by: Martin KaFai Lau Tested-by: Eduard Zingerman Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20241220201818.127152-1-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- include/linux/btf.h | 5 +++++ kernel/bpf/bpf_struct_ops.c | 21 +++++++++++++++++++++ kernel/bpf/btf.c | 5 ----- 3 files changed, 26 insertions(+), 5 deletions(-) diff --git a/include/linux/btf.h b/include/linux/btf.h index b8a583194c4a9..d99178ce01d21 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -352,6 +352,11 @@ static inline bool btf_type_is_scalar(const struct btf_type *t) return btf_type_is_int(t) || btf_type_is_enum(t); } +static inline bool btf_type_is_fwd(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_FWD; +} + static inline bool btf_type_is_typedef(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF; diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index b3a2ce1e5e22e..b70d0eef8a284 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -311,6 +311,20 @@ void bpf_struct_ops_desc_release(struct bpf_struct_ops_desc *st_ops_desc) kfree(arg_info); } +static bool is_module_member(const struct btf *btf, u32 id) +{ + const struct btf_type *t; + + t = btf_type_resolve_ptr(btf, id, NULL); + if (!t) + return false; + + if (!__btf_type_is_struct(t) && !btf_type_is_fwd(t)) + return false; + + return !strcmp(btf_name_by_offset(btf, t->name_off), "module"); +} + int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, struct btf *btf, struct bpf_verifier_log *log) @@ -390,6 +404,13 @@ int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, goto errout; } + if (!st_ops_ids[IDX_MODULE_ID] && is_module_member(btf, member->type)) { + pr_warn("'struct module' btf id not found. Is CONFIG_MODULES enabled? bpf_struct_ops '%s' needs module support.\n", + st_ops->name); + err = -EOPNOTSUPP; + goto errout; + } + func_proto = btf_type_resolve_func_ptr(btf, member->type, NULL); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 41d20b7199c4a..a44f4be592be7 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -498,11 +498,6 @@ bool btf_type_is_void(const struct btf_type *t) return t == &btf_void; } -static bool btf_type_is_fwd(const struct btf_type *t) -{ - return BTF_INFO_KIND(t->info) == BTF_KIND_FWD; -} - static bool btf_type_is_datasec(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC; -- 2.39.5