From 06b2a76d25d3cfbd14680021c1d356c91be6904e Mon Sep 17 00:00:00 2001 From: Yi Yang Date: Fri, 8 Feb 2008 04:21:57 -0800 Subject: Add new string functions strict_strto* and convert kernel params to use them 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/uul, 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 succesive invalid char and converts prefix part to a numeric although input is acctually invalid. This patch tries to fix the aforementioned issues and implements strict_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 strict_strtox instead of simple_strtox to reject any invalid input. 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 /]# [akpm@linux-foundation.org: fix compiler warnings] [akpm@linux-foundation.org: fix off-by-one found by tiwai@suse.de] Signed-off-by: Yi Yang Cc: Greg KH Cc: "Randy.Dunlap" Cc: Takashi Iwai Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/vsprintf.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) (limited to 'lib') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 7b481cea54a..419993f58c6 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -126,6 +126,129 @@ long long simple_strtoll(const char *cp,char **endp,unsigned int base) return simple_strtoull(cp,endp,base); } + +/** + * strict_strtoul - convert a string to an unsigned long strictly + * @cp: The string to be converted + * @base: The number base to use + * @res: The converted result value + * + * strict_strtoul converts a string to an unsigned long only if the + * string is really an unsigned long string, any string containing + * any invalid char at the tail will be rejected and -EINVAL is returned, + * only a newline char at the tail is acceptible because people generally + * change a module parameter in the following way: + * + * echo 1024 > /sys/module/e1000/parameters/copybreak + * + * echo will append a newline to the tail. + * + * It returns 0 if conversion is successful and *res is set to the converted + * value, otherwise it returns -EINVAL and *res is set to 0. + * + * simple_strtoul just ignores the successive invalid characters and + * return the converted value of prefix part of the string. + */ +int strict_strtoul(const char *cp, unsigned int base, unsigned long *res); + +/** + * strict_strtol - convert a string to a long strictly + * @cp: The string to be converted + * @base: The number base to use + * @res: The converted result value + * + * strict_strtol is similiar to strict_strtoul, but it allows the first + * character of a string is '-'. + * + * It returns 0 if conversion is successful and *res is set to the converted + * value, otherwise it returns -EINVAL and *res is set to 0. + */ +int strict_strtol(const char *cp, unsigned int base, long *res); + +/** + * strict_strtoull - convert a string to an unsigned long long strictly + * @cp: The string to be converted + * @base: The number base to use + * @res: The converted result value + * + * strict_strtoull converts a string to an unsigned long long only if the + * string is really an unsigned long long string, any string containing + * any invalid char at the tail will be rejected and -EINVAL is returned, + * only a newline char at the tail is acceptible because people generally + * change a module parameter in the following way: + * + * echo 1024 > /sys/module/e1000/parameters/copybreak + * + * echo will append a newline to the tail of the string. + * + * It returns 0 if conversion is successful and *res is set to the converted + * value, otherwise it returns -EINVAL and *res is set to 0. + * + * simple_strtoull just ignores the successive invalid characters and + * return the converted value of prefix part of the string. + */ +int strict_strtoull(const char *cp, unsigned int base, unsigned long long *res); + +/** + * strict_strtoll - convert a string to a long long strictly + * @cp: The string to be converted + * @base: The number base to use + * @res: The converted result value + * + * strict_strtoll is similiar to strict_strtoull, but it allows the first + * character of a string is '-'. + * + * It returns 0 if conversion is successful and *res is set to the converted + * value, otherwise it returns -EINVAL and *res is set to 0. + */ +int strict_strtoll(const char *cp, unsigned int base, long long *res); + +#define define_strict_strtoux(type, valtype) \ +int strict_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_strict_strtox(type, valtype) \ +int strict_strto##type(const char *cp, unsigned int base, valtype *res) \ +{ \ + int ret; \ + if (*cp == '-') { \ + ret = strict_strtou##type(cp+1, base, res); \ + if (ret != 0) \ + *res = -(*res); \ + } else \ + ret = strict_strtou##type(cp, base, res); \ + \ + return ret; \ +} \ + +define_strict_strtoux(l, unsigned long) +define_strict_strtox(l, long) +define_strict_strtoux(ll, unsigned long long) +define_strict_strtox(ll, long long) + +EXPORT_SYMBOL(strict_strtoul); +EXPORT_SYMBOL(strict_strtol); +EXPORT_SYMBOL(strict_strtoll); +EXPORT_SYMBOL(strict_strtoull); + static int skip_atoi(const char **s) { int i=0; -- cgit v1.2.3