diff options
| -rw-r--r-- | kernel/sysctl.c | 40 |
1 files changed, 39 insertions, 1 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 14f30b4a1b64..1877ebe85c95 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -67,6 +67,8 @@ #include <linux/bpf.h> #include <linux/mount.h> +#include "../lib/kstrtox.h" + #include <linux/uaccess.h> #include <asm/processor.h> @@ -2117,6 +2119,41 @@ static void proc_skip_char(char **buf, size_t *size, const char v) } } +/** + * strtoul_lenient - parse an ASCII formatted integer from a buffer and only + * fail on overflow + * + * @cp: kernel buffer containing the string to parse + * @endp: pointer to store the trailing characters + * @base: the base to use + * @res: where the parsed integer will be stored + * + * In case of success 0 is returned and @res will contain the parsed integer, + * @endp will hold any trailing characters. + * This function will fail the parse on overflow. If there wasn't an overflow + * the function will defer the decision what characters count as invalid to the + * caller. + */ +static int strtoul_lenient(const char *cp, char **endp, unsigned int base, + unsigned long *res) +{ + unsigned long long result; + unsigned int rv; + + cp = _parse_integer_fixup_radix(cp, &base); + rv = _parse_integer(cp, base, &result); + if ((rv & KSTRTOX_OVERFLOW) || (result != (unsigned long)result)) + return -ERANGE; + + cp += rv; + + if (endp) + *endp = (char *)cp; + + *res = (unsigned long)result; + return 0; +} + #define TMPBUFLEN 22 /** * proc_get_long - reads an ASCII formatted integer from a user buffer @@ -2160,7 +2197,8 @@ static int proc_get_long(char **buf, size_t *size, if (!isdigit(*p)) return -EINVAL; - *val = simple_strtoul(p, &p, 0); + if (strtoul_lenient(p, &p, 0, val)) + return -EINVAL; len = p - tmp; |