Prev: [PATCH]: improved strnicmp in lib/string.c
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From: Harvey Harrison on 7 May 2008 14:30
Directly code the strict string conversion functions rather than using
defining macros. Pull out a small helper to check the strict conditions
required at the end of a string (nul-terminated or newline).

Add additional checks in strict_strtol and strict_strtoll for numeric
overflow of the signed types.

Signed-off-by: Harvey Harrison <harvey.harrison(a)gmail.com>
---
lib/vsprintf.c | 144 +++++++++++++++++++++++++++++++++++++-------------------
1 files changed, 96 insertions(+), 48 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 0b39c34..ff0c93d 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -128,6 +128,18 @@ long long simple_strtoll(const char *cp, char **endp, unsigned int base)
return simple_strtoull(cp, endp, base);
}

+/*
+ * Strictly check that the string is nul terminated or has a newline
+ * immediately following len chars.
+ */
+static int strict_checktail(size_t len, const char *cp, const char *tail)
+{
+ if ((*tail == '\0') ||
+ ((len == (size_t)(tail - cp) + 1) && (*tail == '\n')))
+ return 1;
+ else
+ return 0;
+}

/**
* strict_strtoul - convert a string to an unsigned long strictly
@@ -151,7 +163,26 @@ long long simple_strtoll(const char *cp, char **endp, unsigned int base)
* 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);
+int strict_strtoul(const char *cp, unsigned int base, unsigned long *res)
+{
+ char *tail;
+ unsigned long val;
+ size_t len;
+
+ *res = 0;
+ len = strlen(cp);
+ if (len == 0)
+ return -EINVAL;
+
+ val = simple_strtoul(cp, &tail, base);
+ if (strict_checktail(len, cp, tail)) {
+ *res = val;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL(strict_strtoul);

/**
* strict_strtol - convert a string to a long strictly
@@ -165,7 +196,29 @@ int strict_strtoul(const char *cp, unsigned int base, unsigned long *res);
* 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);
+int strict_strtol(const char *cp, unsigned int base, long *res)
+{
+ int ret;
+ unsigned long tmp;
+
+ if (*cp == '-')
+ ret = strict_strtoul(cp + 1, base, &tmp);
+ else
+ ret = strict_strtoul(cp, base, &tmp);
+
+ if (!ret || tmp > LONG_MAX) {
+ *res = 0;
+ return -EINVAL;
+ }
+
+ if (*cp == '-')
+ *res = -tmp;
+ else
+ *res = tmp;
+
+ return 0;
+}
+EXPORT_SYMBOL(strict_strtol);

/**
* strict_strtoull - convert a string to an unsigned long long strictly
@@ -189,7 +242,26 @@ int strict_strtol(const char *cp, unsigned int base, long *res);
* 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);
+int strict_strtoull(const char *cp, unsigned int base, unsigned long long *res)
+{
+ char *tail;
+ unsigned long long val;
+ size_t len;
+
+ *res = 0;
+ len = strlen(cp);
+ if (len == 0)
+ return -EINVAL;
+
+ val = simple_strtoull(cp, &tail, base);
+ if (strict_checktail(len, cp, tail)) {
+ *res = val;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL(strict_strtoull);

/**
* strict_strtoll - convert a string to a long long strictly
@@ -203,53 +275,29 @@ int strict_strtoull(const char *cp, unsigned int base, unsigned long long *res);
* 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) \
- *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)
+int strict_strtoll(const char *cp, unsigned int base, long long *res)
+{
+ int ret;
+ unsigned long long tmp;

-EXPORT_SYMBOL(strict_strtoul);
-EXPORT_SYMBOL(strict_strtol);
+ if (*cp == '-')
+ ret = strict_strtoull(cp + 1, base, &tmp);
+ else
+ ret = strict_strtoull(cp, base, &tmp);
+
+ if (!ret || tmp > LLONG_MAX) {
+ *res = 0;
+ return -EINVAL;
+ }
+
+ if (*cp == '-')
+ *res = -tmp;
+ else
+ *res = tmp;
+
+ return 0;
+}
EXPORT_SYMBOL(strict_strtoll);
-EXPORT_SYMBOL(strict_strtoull);

static int skip_atoi(const char **s)
{
--
1.5.5.1.350.gbbbf

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Prev: [PATCH]: improved strnicmp in lib/string.c
Next: [BUG] 2.6.26-rc1 lost half the RAM on UltraSPARC 5