linux-kernel - [PATCH] kernel/module.c: use scnprintf() instead of sprintf()

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Date:	Tue, 20 Aug 2013 11:13:07 +0800
From:	Chen Gang <gang.chen@...anux.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] kernel/module.c: use scnprintf() instead of sprintf()

For some strings, they are permitted to be larger than PAGE_SIZE, so
need use scnprintf() instead of sprintf(), or it will cause issue.

One case is:

  if a module version is crazy defined (length more than PAGE_SIZE),
  'modinfo' command is still OK (print full contents),
  but for "cat /sys/modules/'modname'/version", will cause issue in kernel.


Signed-off-by: Chen Gang <gang.chen@...anux.com>
---
 kernel/module.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 2069158..0618e63 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -603,7 +603,7 @@ static void setup_modinfo_##field(struct module *mod, const char *s)  \
 static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
 			struct module_kobject *mk, char *buffer)      \
 {                                                                     \
-	return sprintf(buffer, "%s\n", mk->mod->field);               \
+	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
 }                                                                     \
 static int modinfo_##field##_exists(struct module *mod)               \
 {                                                                     \
-- 
1.7.7.6
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