[Patch] sysctl: forbid too long numbers

Amerigo Wang
2009-06-19T07:20:33Z

For some file under /proc/sys/kernel, the valid values for them
are < ULONG_MAX if they don't have they own max value defined. Thus,
numbers longer than are invalid.

So use strict_strtoul() instead of simple_strtoul(), and
make strict_strtoul() more strict.

[I don't know whom I should Cc...]
Signed-off-by: WANG Cong <amwang@redhat.com>

---
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ab462b9..bc27e00 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2331,7 +2331,8 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
if (*p < '0' || *p > '9')
break;

- lval = simple_strtoul(p, &p, 0);
+ if (strict_strtoul(p, 0, &lval))
+ return -EINVAL;

len = p-buf;
if ((len < left) && *p && !isspace(*p))
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 756ccaf..ff2ca5c 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -163,11 +163,14 @@ int strict_strtoul(const char *cp, unsigned int base, unsigned long *res)
char *tail;
unsigned long val;
size_t len;
+ char tmp[32];

*res = 0;
len = strlen(cp);
if (len == 0)
return -EINVAL;
+ if (len > snprintf(tmp, "%ld", ULONG_MAX))
+ return -EINVAL;

val = simple_strtoul(cp, &tail, base);
if (tail == cp)