linux-kernel - [PATCH] lib/kstrtox.c break if overflow is detected

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Date:	Wed, 21 Jan 2015 11:26:26 -0800
From:	Anshul Garg <aksgarg1989@...il.com>
To:	akpm@...ux-foundation.org, levex@...ux.com,
	felipe.contreras@...il.com, linux-kernel@...r.kernel.org
Cc:	aksgarg1989@...il.com, anshul.g@...sung.com
Subject: [PATCH] lib/kstrtox.c break if overflow is detected

From: Anshul Garg <aksgarg1989@...il.com>

1. While converting string representation to integer
break the loop if overflow is detected.
2. Clean kstrtoll function

Signed-off-by: Anshul Garg <aksgarg1989@...il.com>
---
 lib/kstrtox.c |   28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/lib/kstrtox.c b/lib/kstrtox.c
index ec8da78..8cbe5ca 100644
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -70,8 +70,10 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
 		 * it in the max base we support (16)
 		 */
 		if (unlikely(res & (~0ull << 60))) {
-			if (res > div_u64(ULLONG_MAX - val, base))
+			if (res > div_u64(ULLONG_MAX - val, base)) {
 				overflow = 1;
+				break;
+			}
 		}
 		res = res * base + val;
 		rv++;
@@ -146,23 +148,19 @@ EXPORT_SYMBOL(kstrtoull);
 int kstrtoll(const char *s, unsigned int base, long long *res)
 {
 	unsigned long long tmp;
-	int rv;
+	int rv, sign = 1;
 
 	if (s[0] == '-') {
-		rv = _kstrtoull(s + 1, base, &tmp);
-		if (rv < 0)
-			return rv;
-		if ((long long)(-tmp) >= 0)
-			return -ERANGE;
-		*res = -tmp;
-	} else {
-		rv = kstrtoull(s, base, &tmp);
-		if (rv < 0)
-			return rv;
-		if ((long long)tmp < 0)
-			return -ERANGE;
-		*res = tmp;
+		sign = -1;
+		s++;
 	}
+
+	rv = kstrtoull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if ((long long)tmp < 0)
+		return -ERANGE;
+	*res = sign * tmp;
 	return 0;
 }
 EXPORT_SYMBOL(kstrtoll);
-- 
1.7.9.5


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