From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 BCB0C3E9299; Thu, 21 May 2026 13:33:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779370412; cv=none; b=ZQqw0O0Qhekez2lfzJrddNsBMiJZHjcHJ8QiHMi1hl+8aNxD1g27BBsbY4Ttbo1/lNvQxUdCgqPl9JwCNsgAhJrBWsXrQUnWAyHeWQBAr0Pg4gRfsocr5jnOHLfANn4QqlIqOt3vdxNsA9znq65vqDEKXaEoha4KS508Chq5l08= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779370412; c=relaxed/simple; bh=cZc+JELjQTK8ycLqZtLTkP9aHNuVqrWgrD/YlzSeCsM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=F4dV8Pgo7JmVbJ/omKSam9fMN9KFzg+AEuQj2J8pVEuo5r3K+wAPtGUMl6fOzEobqBKfp0nLO/Y55LwMIHztvgZ3/Rm7nFHTmkvF7BpcuTheBOn7KTvvtovAZyV1nYPhQ9ukfR7L+H0VynC7VpKgDXhIWYj9riX7Avk6K66lVzM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=faqBkEGM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="faqBkEGM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FC0C1F01579; Thu, 21 May 2026 13:33:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779370407; bh=xwIDnz4Pf2a/0Wouv4cV1Bk8/fwt1/yHjZ8WyMRsm0E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=faqBkEGM4aU15rBNkXIkUKRG5AsCe1S2Aewj2Tv1k/O0IFENHWQB9BDl0qYlYUXx1 yoSYnXrOdkYgaAvt93OzOSpjQt1HbLSZILUsO+WwAhtrliX5J0FzgX8CuujFmAl5jz X8uTF9W4laMnV0lw73DuAepv0e1Z18zWI5AlF6sh7C8rwcqpQzvp1cimaV2in+YUgi OE4BwyWmDWxhcTmmdjqIRpFm9oVrWPKzXOPW22NTkxkdTVTWD9EOmYqsfX8zmiSFqR Z0nWrODWYXeXSYKufMtwTaK1WxYbFWleRdtaUyw1XtWk0UguQM98XV3sxBpbdWcKqK 7ltRkG3vLauMQ== From: Kees Cook To: Luis Chamberlain Cc: Kees Cook , Pengpeng Hou , Petr Pavlu , Richard Weinberger , Anton Ivanov , Johannes Berg , "Rafael J. Wysocki" , Len Brown , Corey Minyard , Gabriel Somlo , "Michael S. Tsirkin" , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Bart Van Assche , Jason Gunthorpe , Leon Romanovsky , Laurent Pinchart , Hans de Goede , Mauro Carvalho Chehab , Bjorn Helgaas , Hannes Reinecke , "James E.J. Bottomley" , "Martin K. Petersen" , Daniel Lezcano , Zhang Rui , Lukasz Luba , Greg Kroah-Hartman , Jiri Slaby , Alan Stern , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Jason Baron , Jim Cromie , Tiwei Bie , Benjamin Berg , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , "David E. Box" , "Maciej W. Rozycki" , Srinivas Pandruvada , Peter Zijlstra , Heiko Carstens , Vasily Gorbik , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Vinod Koul , Frank Li , Daniel Gomez , Sami Tolvanen , Aaron Tomlin , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , John Johansen , Paul Moore , James Morris , "Serge E. Hallyn" , Andy Shevchenko , Georgia Garcia , kvm@vger.kernel.org, dmaengine@vger.kernel.org, linux-modules@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org, linux-um@lists.infradead.org, linux-acpi@vger.kernel.org, openipmi-developer@lists.sourceforge.net, qemu-devel@nongnu.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, usb-storage@lists.one-eyed-alien.net, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH 11/11] moduleparam: Drop legacy kernel_param_ops .get_str field and dispatch logic Date: Thu, 21 May 2026 06:33:24 -0700 Message-Id: <20260521133326.2465264-11-kees@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260521133315.work.845-kees@kernel.org> References: <20260521133315.work.845-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6078; i=kees@kernel.org; h=from:subject; bh=cZc+JELjQTK8ycLqZtLTkP9aHNuVqrWgrD/YlzSeCsM=; b=owGbwMvMwCVmps19z/KJym7G02pJDFn8nEvufDYVreO77zyVZ9nKv/dmtn67mvlTQuv4kafPq puKFFykO0pZGMS4GGTFFFmC7NzjXDzetoe7z1WEmcPKBDKEgYtTACZyUpThn+GuD2261nV35Y9v WCSkdjztcECEh/yOmilbnsu+Me2RqGb4X3Y7PuFYwqXlesy7khtcFv4xWB144Q33rOMlXKUF6Yq CDAA= X-Developer-Key: i=kees@kernel.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit All struct kernel_param_ops .get callbacks have been migrated to using struct seq_buf. Drop the migration scaffolding. Signed-off-by: Kees Cook --- include/linux/moduleparam.h | 37 ++-------------------- kernel/params.c | 62 ++++++++++--------------------------- 2 files changed, 20 insertions(+), 79 deletions(-) diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 38acb5aef56b..e6af6f051c93 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -66,15 +66,8 @@ struct kernel_param_ops { /* * Format the parameter's value into @s. Return 0 on success * (length derived from seq_buf_used()) or -errno on error. - * Exactly one of .get and .get_str should be set; the dispatcher - * WARNs and prefers .get if both are. */ int (*get)(struct seq_buf *s, const struct kernel_param *kp); - /* - * Returns length written or -errno. Buffer is 4k (ie. be short!). - * Deprecated: callbacks should implement .get instead. - */ - int (*get_str)(char *buffer, const struct kernel_param *kp); /* Optional function to free kp->arg when module unloaded. */ void (*free)(void *arg); }; @@ -84,33 +77,11 @@ struct kernel_param_ops { * any required visibility qualifiers (typically "static"): * * static DEFINE_KERNEL_PARAM_OPS(my_ops, my_set, my_get); - * - * @_get may be either of: - * int (*)(struct seq_buf *, const struct kernel_param *) (seq_buf) - * int (*)(char *, const struct kernel_param *) (legacy) - * - * The macro uses _Generic to route the function pointer to the - * matching field (.get or .get_str) at compile time, leaving the - * other field NULL. Each helper matches the wrong prototype signature - * and returns NULL, falling through to the default branch otherwise; - * if @_get has neither expected signature the assignment to the - * fields gets a normal compile-time type-mismatch error. */ -#define _KERNEL_PARAM_OPS_GET(_get) \ - _Generic((_get), \ - int (*)(char *, const struct kernel_param *): NULL, \ - default: (_get)) - -#define _KERNEL_PARAM_OPS_GET_STR(_get) \ - _Generic((_get), \ - int (*)(struct seq_buf *, const struct kernel_param *): NULL, \ - default: (_get)) - #define DEFINE_KERNEL_PARAM_OPS(_name, _set, _get) \ const struct kernel_param_ops _name = { \ .set = (_set), \ - .get = _KERNEL_PARAM_OPS_GET(_get), \ - .get_str = _KERNEL_PARAM_OPS_GET_STR(_get), \ + .get = (_get), \ } /* As DEFINE_KERNEL_PARAM_OPS, with KERNEL_PARAM_OPS_FL_NOARG set. */ @@ -118,16 +89,14 @@ struct kernel_param_ops { const struct kernel_param_ops _name = { \ .flags = KERNEL_PARAM_OPS_FL_NOARG, \ .set = (_set), \ - .get = _KERNEL_PARAM_OPS_GET(_get), \ - .get_str = _KERNEL_PARAM_OPS_GET_STR(_get), \ + .get = (_get), \ } /* As DEFINE_KERNEL_PARAM_OPS, with an additional .free callback. */ #define DEFINE_KERNEL_PARAM_OPS_FREE(_name, _set, _get, _free) \ const struct kernel_param_ops _name = { \ .set = (_set), \ - .get = _KERNEL_PARAM_OPS_GET(_get), \ - .get_str = _KERNEL_PARAM_OPS_GET_STR(_get), \ + .get = (_get), \ .free = (_free), \ } diff --git a/kernel/params.c b/kernel/params.c index 25f0c8d5d19f..6b410189297b 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -461,8 +461,7 @@ static int param_array_get(struct seq_buf *s, const struct kernel_param *kp) { const struct kparam_array *arr = kp->arr; struct kernel_param p = *kp; - char *elem_buf = NULL; - int i, ret = 0; + int i, ret; for (i = 0; i < (arr->num ? *arr->num : arr->max); i++) { size_t before = s->len; @@ -470,23 +469,9 @@ static int param_array_get(struct seq_buf *s, const struct kernel_param *kp) p.arg = arr->elem + arr->elemsize * i; check_kparam_locked(p.mod); - if (arr->ops->get) { - ret = arr->ops->get(s, &p); - if (ret < 0) - goto out; - } else { - if (!elem_buf) { - elem_buf = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!elem_buf) { - ret = -ENOMEM; - goto out; - } - } - ret = arr->ops->get_str(elem_buf, &p); - if (ret < 0) - goto out; - seq_buf_putmem(s, elem_buf, ret); - } + ret = arr->ops->get(s, &p); + if (ret < 0) + return ret; /* Nothing got written (e.g. overflow) — stop. */ if (s->len == before) @@ -496,10 +481,7 @@ static int param_array_get(struct seq_buf *s, const struct kernel_param *kp) if (i && s->buffer[before - 1] == '\n') s->buffer[before - 1] = ','; } - ret = 0; -out: - kfree(elem_buf); - return ret; + return 0; } static void param_array_free(void *arg) @@ -570,32 +552,22 @@ static ssize_t param_attr_show(const struct module_attribute *mattr, int count; const struct param_attribute *attribute = to_param_attr(mattr); const struct kernel_param_ops *ops = attribute->param->ops; + struct seq_buf s; - if (!ops->get && !ops->get_str) + if (!ops->get) return -EPERM; - WARN_ON_ONCE(ops->get && ops->get_str); - kernel_param_lock(mk->mod); - if (ops->get) { - struct seq_buf s; - - seq_buf_init(&s, buf, PAGE_SIZE); - count = ops->get(&s, attribute->param); - if (count >= 0) { - WARN_ON_ONCE(count > 0); - count = seq_buf_used(&s); - /* Make sure string is terminated. */ - seq_buf_str(&s); - /* - * If overflowed, reduce count by 1 for trailing - * NUL byte. - */ - if (seq_buf_has_overflowed(&s)) - count--; - } - } else { - count = ops->get_str(buf, attribute->param); + seq_buf_init(&s, buf, PAGE_SIZE); + count = ops->get(&s, attribute->param); + if (count >= 0) { + WARN_ON_ONCE(count > 0); + count = seq_buf_used(&s); + /* Make sure string is terminated. */ + seq_buf_str(&s); + /* If overflowed, reduce count by 1 for trailing NUL byte. */ + if (seq_buf_has_overflowed(&s)) + count--; } kernel_param_unlock(mk->mod); return count; -- 2.34.1