[PATCH 2.6.24] Add new string functions real_strtoul and changekernel params to use them
From: Yi Yang
Date: Thu Jan 31 2008 - 05:34:31 EST
Currently, for every sysfs node, the callers will be responsible for
implementing store operation, so many many callers are doing duplicate
things to validate input, they have the same mistakes because they are
calling simple_strtol/ul/ll/ull, especially for module params, they are
just numeric, but you can echo such values as 0x1234xxx, 07777888 and
1234aaa, for these cases, module params store operation just ignores
successive invalid char and converts prefix part to a numeric although
input is actually invalid.
This patch tries to fix the aforementioned issues and implements real_strtox
serial functions, kernel/params.c uses them to strictly validate input,
so module params will reject such values as 0x1234xxxx and returns an error:
write error: Invalid argument
Any modules which export numeric sysfs node can use real_strtox instead of
simple_strtox to reject any invalid input. Please consider to merge to -mm tree
in order to test.
Here are some test results:
Before applying this patch:
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000g > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000gggggggg > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 010000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0100008 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 010000aaaaa > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]#
After applying this patch:
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000g > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000gggggggg > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# echo 010000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# echo 0100008 > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# echo 010000aaaaa > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo -n 4096 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]#
Signed-off-by: Yi Yang <yi.y.yang@xxxxxxxxx>
---
include/linux/kernel.h | 4 ++++
kernel/params.c | 20 ++++++++++----------
lib/vsprintf.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 60 insertions(+), 10 deletions(-)
--- a/include/linux/kernel.h 2008-01-31 00:41:46.000000000 +0800
+++ b/include/linux/kernel.h 2008-01-31 01:12:33.000000000 +0800
@@ -141,6 +141,10 @@ extern unsigned long simple_strtoul(cons
extern long simple_strtol(const char *,char **,unsigned int);
extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
extern long long simple_strtoll(const char *,char **,unsigned int);
+extern int real_strtoul(const char *, unsigned int, unsigned long *);
+extern int real_strtol(const char *, unsigned int, long *);
+extern int real_strtoull(const char *, unsigned int, unsigned long long *);
+extern int real_strtoll(const char *, unsigned int, long long *);
extern int sprintf(char * buf, const char * fmt, ...)
__attribute__ ((format (printf, 2, 3)));
extern int vsprintf(char *buf, const char *, va_list)
--- a/lib/vsprintf.c 2008-01-30 08:13:03.000000000 +0800
+++ b/lib/vsprintf.c 2008-01-31 05:19:31.000000000 +0800
@@ -126,6 +126,52 @@ long long simple_strtoll(const char *cp,
return simple_strtoull(cp,endp,base);
}
+#define define_real_strtoux(type, valtype) \
+int real_strtou##type(const char *cp, unsigned int base, valtype *res) \
+{ \
+ char *tail; \
+ valtype val; \
+ size_t len; \
+ \
+ *res = 0; \
+ len = strlen(cp); \
+ if (len == 0) \
+ return -EINVAL; \
+ \
+ val = simple_strtoul(cp, &tail, base); \
+ if ((*tail == '\0') || \
+ (len == (size_t)(tail - cp) + 1) && (*tail == '\n')) { \
+ *res = val; \
+ return 0; \
+ } \
+ \
+ return -EINVAL; \
+} \
+
+#define define_real_strtox(type, valtype) \
+int real_strto##type(const char *cp, unsigned int base, valtype *res) \
+{ \
+ int ret; \
+ if (*cp == '-') { \
+ ret = real_strtou##type(cp+1, base, res); \
+ if (ret != 0) \
+ *res = -(*res); \
+ } else \
+ ret = real_strtou##type(cp+1, base, res); \
+ \
+ return ret; \
+} \
+
+define_real_strtoux(l, unsigned long)
+define_real_strtox(l, long)
+define_real_strtoux(ll, unsigned long long)
+define_real_strtox(ll, long long)
+
+EXPORT_SYMBOL(real_strtoul);
+EXPORT_SYMBOL(real_strtol);
+EXPORT_SYMBOL(real_strtoll);
+EXPORT_SYMBOL(real_strtoull);
+
static int skip_atoi(const char **s)
{
int i=0;
--- a/kernel/params.c 2008-01-31 00:44:44.000000000 +0800
+++ b/kernel/params.c 2008-01-31 01:11:51.000000000 +0800
@@ -180,12 +180,12 @@ int parse_args(const char *name,
#define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn) \
int param_set_##name(const char *val, struct kernel_param *kp) \
{ \
- char *endp; \
tmptype l; \
+ int ret; \
\
if (!val) return -EINVAL; \
- l = strtolfn(val, &endp, 0); \
- if (endp == val || ((type)l != l)) \
+ ret = strtolfn(val, 0, &l); \
+ if (ret == -EINVAL || ((type)l != l)) \
return -EINVAL; \
*((type *)kp->arg) = l; \
return 0; \
@@ -195,13 +195,13 @@ int parse_args(const char *name,
return sprintf(buffer, format, *((type *)kp->arg)); \
}
-STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, simple_strtoul);
-STANDARD_PARAM_DEF(short, short, "%hi", long, simple_strtol);
-STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, simple_strtoul);
-STANDARD_PARAM_DEF(int, int, "%i", long, simple_strtol);
-STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, simple_strtoul);
-STANDARD_PARAM_DEF(long, long, "%li", long, simple_strtol);
-STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, simple_strtoul);
+STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, real_strtoul);
+STANDARD_PARAM_DEF(short, short, "%hi", long, real_strtol);
+STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, real_strtoul);
+STANDARD_PARAM_DEF(int, int, "%i", long, real_strtol);
+STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, real_strtoul);
+STANDARD_PARAM_DEF(long, long, "%li", long, real_strtol);
+STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, real_strtoul);
int param_set_charp(const char *val, struct kernel_param *kp)
{
--
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