linux-kernel - [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210121074959.313333-6-hch@lst.de>
Date:   Thu, 21 Jan 2021 08:49:51 +0100
From:   Christoph Hellwig <hch@....de>
To:     Frederic Barrat <fbarrat@...ux.ibm.com>,
        Andrew Donnellan <ajd@...ux.ibm.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, Jessica Yu <jeyu@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Jiri Kosina <jikos@...nel.org>,
        Miroslav Benes <mbenes@...e.cz>,
        Petr Mladek <pmladek@...e.com>,
        Joe Lawrence <joe.lawrence@...hat.com>
Cc:     Masahiro Yamada <masahiroy@...nel.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        dri-devel@...ts.freedesktop.org, live-patching@...r.kernel.org,
        linux-kbuild@...r.kernel.org
Subject: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol

Require an explicit cll to module_kallsyms_on_each_symbol to look
for symbols in modules instead of the call from kallsyms_on_each_symbol,
and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
of leaving that up to the caller.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 kernel/kallsyms.c       | 6 +++++-
 kernel/livepatch/core.c | 6 +-----
 kernel/module.c         | 8 ++++----
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fe9de067771c34..a0d3f0865916f9 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,10 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data)
@@ -192,7 +196,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 		if (ret != 0)
 			return ret;
 	}
-	return module_kallsyms_on_each_symbol(fn, data);
+	return 0;
 }
 
 static unsigned long get_symbol_pos(unsigned long addr,
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 878759baadd81c..8063b9089bd2f8 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -135,12 +135,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 		.pos = sympos,
 	};
 
-	mutex_lock(&module_mutex);
-	if (objname)
+	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
-	else
-		kallsyms_on_each_symbol(klp_find_callback, &args);
-	mutex_unlock(&module_mutex);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
diff --git a/kernel/module.c b/kernel/module.c
index 299cbac0775cf2..885feec64c1b6f 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4407,8 +4407,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
-	module_assert_mutex();
-
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4424,10 +4423,11 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
 #endif /* CONFIG_KALLSYMS */
 
-- 
2.29.2