| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <28a942f860ccdee05751dcccc74b70e9d64f2b94.1652113087.git.mchehab@kernel.org>
Date: Mon, 9 May 2022 18:23:37 +0200
From: Mauro Carvalho Chehab <mchehab@...nel.org>
To: Luis Chamberlain <mcgrof@...nel.org>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
"Daniel Vetter" <daniel@...ll.ch>,
"David Airlie" <airlied@...ux.ie>,
"Greg KH" <gregkh@...uxfoundation.org>,
"Jaroslav Kysela" <perex@...ex.cz>,
"Kai Vehmanen" <kai.vehmanen@...el.com>,
"Lucas De Marchi" <lucas.demarchi@...el.com>,
"Pierre-Louis Bossart" <pierre-louis.bossart@...el.com>,
"Takashi Iwai" <tiwai@...e.com>, alsa-devel@...a-project.org,
dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
linux-kernel@...r.kernel.org, linux-modules@...r.kernel.org,
mauro.chehab@...ux.intel.com,
Dan Williams <dan.j.williams@...el.com>
Subject: [PATCH v6 2/4] module: update dependencies at try_module_get()
Sometimes, device drivers are bound into each other via try_module_get(),
making such references invisible when looking at /proc/modules or lsmod.
Add a function to allow setting up module references for such
cases, and call it when try_module_get() is used.
Reviewed-by: Dan Williams <dan.j.williams@...el.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
---
See [PATCH v6 0/4] at: https://lore.kernel.org/all/cover.1652113087.git.mchehab@kernel.org/
include/linux/module.h | 8 +++--
kernel/module/main.c | 73 ++++++++++++++++++++++++++++++++++--------
2 files changed, 64 insertions(+), 17 deletions(-)
diff --git a/include/linux/module.h b/include/linux/module.h
index 77961f5773b6..a66b9be92ef5 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -618,12 +618,12 @@ extern void __module_get(struct module *module);
/* This is the Right Way to get a module: if it fails, it's being removed,
* so pretend it's not there. */
-extern bool try_module_get(struct module *module);
+extern bool try_module_get_owner(struct module *module, struct module *this);
extern void module_put(struct module *module);
#else /*!CONFIG_MODULE_UNLOAD*/
-static inline bool try_module_get(struct module *module)
+static inline bool try_module_get_owner(struct module *module, struct module *this)
{
return !module || module_is_live(module);
}
@@ -752,7 +752,7 @@ static inline void __module_get(struct module *module)
{
}
-static inline bool try_module_get(struct module *module)
+static inline bool try_module_get_owner(struct module *module, struct module *this)
{
return true;
}
@@ -893,6 +893,8 @@ static inline bool module_sig_ok(struct module *module)
}
#endif /* CONFIG_MODULE_SIG */
+#define try_module_get(mod) try_module_get_owner(mod, THIS_MODULE)
+
int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
struct module *, unsigned long),
void *data);
diff --git a/kernel/module/main.c b/kernel/module/main.c
index fe44d46c378b..6044aeba0f18 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -139,6 +139,24 @@ int unregister_module_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL(unregister_module_notifier);
+static bool __try_module_get(struct module *module)
+{
+ bool ret = true;
+
+ if (module) {
+ preempt_disable();
+ /* Note: here, we can fail to get a reference */
+ if (likely(module_is_live(module) &&
+ atomic_inc_not_zero(&module->refcnt) != 0))
+ trace_module_get(module, _RET_IP_);
+ else
+ ret = false;
+
+ preempt_enable();
+ }
+ return ret;
+}
+
/*
* We require a truly strong try_module_get(): 0 means success.
* Otherwise an error is returned due to ongoing or failed
@@ -149,7 +167,7 @@ static inline int strong_try_module_get(struct module *mod)
BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
if (mod && mod->state == MODULE_STATE_COMING)
return -EBUSY;
- if (try_module_get(mod))
+ if (__try_module_get(mod))
return 0;
else
return -ENOENT;
@@ -620,6 +638,41 @@ static int ref_module(struct module *a, struct module *b)
return 0;
}
+static int ref_module_dependency(struct module *mod, struct module *this)
+{
+ int ret = 0;
+
+ if (!this || !mod || !this->name || !mod->holders_dir)
+ return -EINVAL;
+
+ if (mod == this)
+ return 0;
+
+ mutex_lock(&module_mutex);
+
+ if (already_uses(this, mod))
+ goto ret;
+
+ ret = strong_try_module_get(mod);
+ if (ret)
+ goto ret;
+
+ ret = add_module_usage(this, mod);
+ if (ret) {
+ module_put(mod);
+ goto ret;
+ }
+
+#ifdef CONFIG_MODULE_UNLOAD
+ ret = sysfs_create_link(mod->holders_dir,
+ &this->mkobj.kobj, this->name);
+#endif
+
+ret:
+ mutex_unlock(&module_mutex);
+ return ret;
+}
+
/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
@@ -830,24 +883,16 @@ void __module_get(struct module *module)
}
EXPORT_SYMBOL(__module_get);
-bool try_module_get(struct module *module)
+bool try_module_get_owner(struct module *module, struct module *this)
{
- bool ret = true;
+ int ret = __try_module_get(module);
- if (module) {
- preempt_disable();
- /* Note: here, we can fail to get a reference */
- if (likely(module_is_live(module) &&
- atomic_inc_not_zero(&module->refcnt) != 0))
- trace_module_get(module, _RET_IP_);
- else
- ret = false;
+ if (ret)
+ ref_module_dependency(module, this);
- preempt_enable();
- }
return ret;
}
-EXPORT_SYMBOL(try_module_get);
+EXPORT_SYMBOL(try_module_get_owner);
void module_put(struct module *module)
{
--
2.35.3
Powered by blists - more mailing lists