1 files changed, 48 insertions, 34 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 4a990f3fd345..83b164707e5c 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -46,6 +46,31 @@
 #include <linux/string_helpers.h>
 #include "kstrtox.h"
 
+static unsigned long long simple_strntoull(const char *startp, size_t max_chars,
+					   char **endp, unsigned int base)
+{
+	const char *cp;
+	unsigned long long result = 0ULL;
+	size_t prefix_chars;
+	unsigned int rv;
+
+	cp = _parse_integer_fixup_radix(startp, &base);
+	prefix_chars = cp - startp;
+	if (prefix_chars < max_chars) {
+		rv = _parse_integer_limit(cp, base, &result, max_chars - prefix_chars);
+		/* FIXME */
+		cp += (rv & ~KSTRTOX_OVERFLOW);
+	} else {
+		/* Field too short for prefix + digit, skip over without converting */
+		cp = startp + max_chars;
+	}
+
+	if (endp)
+		*endp = (char *)cp;
+
+	return result;
+}
+
 /**
  * simple_strtoull - convert a string to an unsigned long long
  * @cp: The start of the string
@@ -56,18 +81,7 @@
  */
 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
 {
-	unsigned long long result;
-	unsigned int rv;
-
-	cp = _parse_integer_fixup_radix(cp, &base);
-	rv = _parse_integer(cp, base, &result);
-	/* FIXME */
-	cp += (rv & ~KSTRTOX_OVERFLOW);
-
-	if (endp)
-		*endp = (char *)cp;
-
-	return result;
+	return simple_strntoull(cp, INT_MAX, endp, base);
 }
 EXPORT_SYMBOL(simple_strtoull);
 
@@ -102,6 +116,21 @@ long simple_strtol(const char *cp, char **endp, unsigned int base)
 }
 EXPORT_SYMBOL(simple_strtol);
 
+static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
+				 unsigned int base)
+{
+	/*
+	 * simple_strntoull() safely handles receiving max_chars==0 in the
+	 * case cp[0] == '-' && max_chars == 1.
+	 * If max_chars == 0 we can drop through and pass it to simple_strntoull()
+	 * and the content of *cp is irrelevant.
+	 */
+	if (*cp == '-' && max_chars > 0)
+		return -simple_strntoull(cp + 1, max_chars - 1, endp, base);
+
+	return simple_strntoull(cp, max_chars, endp, base);
+}
+
 /**
  * simple_strtoll - convert a string to a signed long long
  * @cp: The start of the string
@@ -112,10 +141,7 @@ EXPORT_SYMBOL(simple_strtol);
  */
 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
 {
-	if (*cp == '-')
-		return -simple_strtoull(cp + 1, endp, base);
-
-	return simple_strtoull(cp, endp, base);
+	return simple_strntoll(cp, INT_MAX, endp, base);
 }
 EXPORT_SYMBOL(simple_strtoll);
 
@@ -2943,25 +2969,13 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
 			break;
 
 		if (is_sign)
-			val.s = qualifier != 'L' ?
-				simple_strtol(str, &next, base) :
-				simple_strtoll(str, &next, base);
+			val.s = simple_strntoll(str,
+						field_width >= 0 ? field_width : INT_MAX,
+						&next, base);
 		else
-			val.u = qualifier != 'L' ?
-				simple_strtoul(str, &next, base) :
-				simple_strtoull(str, &next, base);
-
-		if (field_width > 0 && next - str > field_width) {
-			if (base == 0)
-				_parse_integer_fixup_radix(str, &base);
-			while (next - str > field_width) {
-				if (is_sign)
-					val.s = div_s64(val.s, base);
-				else
-					val.u = div_u64(val.u, base);
-				--next;
-			}
-		}
+			val.u = simple_strntoull(str,
+						 field_width >= 0 ? field_width : INT_MAX,
+						 &next, base);
 
 		switch (qualifier) {
 		case 'H':	/* that's 'hh' in format */