From: Julien Thierry <jthierry@redhat.com>
To: Petr Mladek <pmladek@suse.com>, Jiri Kosina <jikos@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Miroslav Benes <mbenes@suse.cz>
Cc: Joe Lawrence <joe.lawrence@redhat.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Nicolai Stange <nstange@suse.de>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [POC 03/23] livepatch: Better checks of struct klp_object definition
Date: Tue, 21 Jan 2020 11:27:17 +0000 [thread overview]
Message-ID: <a5327513-a208-a3c1-cbff-5e978a21b230@redhat.com> (raw)
In-Reply-To: <20200117150323.21801-4-pmladek@suse.com>
Hi Petr,
On 1/17/20 3:03 PM, Petr Mladek wrote:
> The number of user defined fields increased in struct klp_object after
> spliting per-object livepatches. It was sometimes unclear why exactly
> the module could not get loded when returned -EINVAL.
>
> Add more checks for the split modules and write useful error
> messages on particular errors.
>
> Signed-off-by: Petr Mladek <pmladek@suse.com>
> ---
> kernel/livepatch/core.c | 91 ++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 82 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index bb62c5407b75..ec7ffc7db3a7 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -756,9 +756,6 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
> int ret;
> const char *name;
>
> - if (klp_is_module(obj) && strlen(obj->name) >= MODULE_NAME_LEN)
> - return -EINVAL;
> -
> obj->patched = false;
>
> name = obj->name ? obj->name : "vmlinux";
> @@ -851,8 +848,86 @@ static int klp_init_patch(struct klp_patch *patch)
> return 0;
> }
>
> +static int klp_check_module_name(struct klp_object *obj, bool is_module)
> +{
> + char mod_name[MODULE_NAME_LEN];
> + const char *expected_name;
> +
> + if (is_module) {
> + snprintf(mod_name, sizeof(mod_name), "%s__%s",
> + obj->patch_name, obj->name);
> + expected_name = mod_name;
> + } else {
> + expected_name = obj->patch_name;
> + }
> +
> + if (strcmp(expected_name, obj->mod->name)) {
I'm not sure I understand the point of enforcing this.
> + pr_err("The module name %s does not match with obj->patch_name and obj->name. The expected name is: %s\n",
> + obj->mod->name, expected_name);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int klp_check_object(struct klp_object *obj, bool is_module)
> +{
> +
> + if (!obj->mod)
> + return -EINVAL;
> +
> + if (!is_livepatch_module(obj->mod)) {
> + pr_err("module %s is not marked as a livepatch module\n",
> + obj->mod->name);
> + return -EINVAL;
> + }
> +
> + if (!obj->patch_name) {
> + pr_err("module %s does not have set obj->patch_name\n",
> + obj->mod->name);
> + return -EINVAL;
> + }
> +
> + if (strlen(obj->patch_name) >= MODULE_NAME_LEN) {
> + pr_err("module %s has too long obj->patch_name\n",
> + obj->mod->name);
> + return -EINVAL;
> + }
> +
> + if (is_module) {
> + if (!obj->name) {
> + pr_err("module %s does not have set obj->name\n",
> + obj->mod->name);
> + return -EINVAL;
> + }
> + if (strlen(obj->name) >= MODULE_NAME_LEN) {
> + pr_err("module %s has too long obj->name\n",
> + obj->mod->name);
> + return -EINVAL;
> + }
> + } else if (obj->name) {
> + pr_err("module %s for vmlinux must not have set obj->name\n",
> + obj->mod->name);
> + return -EINVAL;
> + }
> +
> + if (!obj->funcs) {
> + pr_err("module %s does not have set obj->funcs\n",
> + obj->mod->name);
> + return -EINVAL;
> + }
> +
> + return klp_check_module_name(obj, is_module);
> +}
> +
> int klp_add_object(struct klp_object *obj)
> {
> + int ret;
> +
> + ret = klp_check_object(obj, true);
> + if (ret)
> + return ret;
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(klp_add_object);
> @@ -958,14 +1033,12 @@ int klp_enable_patch(struct klp_patch *patch)
> {
> int ret;
>
> - if (!patch || !patch->obj || !patch->obj->mod)
> + if (!patch || !patch->obj)
> return -EINVAL;
>
> - if (!is_livepatch_module(patch->obj->mod)) {
> - pr_err("module %s is not marked as a livepatch module\n",
> - patch->obj->patch_name);
> - return -EINVAL;
> - }
> + ret = klp_check_object(patch->obj, false);
> + if (ret)
> + return ret;
>
> if (!klp_initialized())
> return -ENODEV;
>
Otherwise this looks good to me.
Cheers,
--
Julien Thierry
next prev parent reply other threads:[~2020-01-21 11:27 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-17 15:03 [POC 00/23] livepatch: Split livepatch module per-object Petr Mladek
2020-01-17 15:03 ` [POC 01/23] module: Allow to delete module also from inside kernel Petr Mladek
2020-01-21 11:11 ` Julien Thierry
2020-01-17 15:03 ` [POC 02/23] livepatch: Split livepatch modules per livepatched object Petr Mladek
2020-01-21 11:11 ` Julien Thierry
2020-01-28 12:16 ` Petr Mladek
2020-01-17 15:03 ` [POC 03/23] livepatch: Better checks of struct klp_object definition Petr Mladek
2020-01-21 11:27 ` Julien Thierry [this message]
2020-01-17 15:03 ` [POC 04/23] livepatch: Prevent loading livepatch sub-module unintentionally Petr Mladek
2020-04-03 17:54 ` Joe Lawrence
2020-01-17 15:03 ` [POC 05/23] livepatch: Initialize and free livepatch submodule Petr Mladek
2020-01-21 11:58 ` Julien Thierry
2020-01-17 15:03 ` [POC 06/23] livepatch: Enable the " Petr Mladek
2020-01-17 15:03 ` [POC 07/23] livepatch: Remove obsolete functionality from klp_module_coming() Petr Mladek
2020-01-17 15:03 ` [POC 08/23] livepatch: Automatically load livepatch module when the patch module is loaded Petr Mladek
2020-01-17 15:03 ` [POC 09/23] livepatch: Handle race when livepatches are reloaded during a module load Petr Mladek
2020-01-22 18:51 ` Julien Thierry
2020-01-17 15:03 ` [POC 10/23] livepatch: Handle modprobe exit code Petr Mladek
2020-01-17 15:03 ` [POC 11/23] livepatch: Safely detect forced transition when removing split livepatch modules Petr Mladek
2020-01-22 10:15 ` Julien Thierry
2020-01-17 15:03 ` [POC 12/23] livepatch: Automatically remove livepatch module when the object is freed Petr Mladek
2020-01-17 15:03 ` [POC 13/23] livepatch: Remove livepatch module when the livepatched module is unloaded Petr Mladek
2020-01-17 15:03 ` [POC 14/23] livepatch: Never block livepatch modules when the related module is being removed Petr Mladek
2020-01-17 15:03 ` [POC 15/23] livepatch: Prevent infinite loop when loading livepatch module Petr Mladek
2020-01-17 15:03 ` [POC 16/23] livepatch: Add patch into the global list early Petr Mladek
2020-01-17 15:03 ` [POC 17/23] livepatch: Load livepatches for modules when loading the main livepatch Petr Mladek
2020-01-17 15:03 ` [POC 18/23] module: Refactor add_unformed_module() Petr Mladek
2020-01-17 15:03 ` [POC 19/23] module/livepatch: Allow to use exported symbols from livepatch module for "vmlinux" Petr Mladek
2020-04-06 18:48 ` Joe Lawrence
2020-04-07 7:33 ` Miroslav Benes
2020-04-07 20:57 ` Joe Lawrence
2020-01-17 15:03 ` [POC 20/23] module/livepatch: Relocate local variables in the module loaded when the livepatch is being loaded Petr Mladek
2020-01-18 10:29 ` kbuild test robot
2020-04-03 18:00 ` Joe Lawrence
2020-01-17 15:03 ` [POC 21/23] livepatch: Remove obsolete arch_klp_init_object_loaded() Petr Mladek
2020-01-17 15:03 ` [POC 22/23] livepatch/module: Remove obsolete copy_module_elf() Petr Mladek
2020-04-03 18:03 ` Joe Lawrence
2020-01-17 15:03 ` [POC 23/23] module: Remove obsolete module_disable_ro() Petr Mladek
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