linux-kernel - strict_strto* is not strict enough

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Message-ID: <20081122203341.GA1895@elf.ucw.cz>
Date:	Sat, 22 Nov 2008 21:33:41 +0100
From:	Pavel Machek <pavel@...e.cz>
To:	kernel list <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...l.org>
Subject: strict_strto* is not strict enough


It decodes "\n" as 0, which is bad, because stray echo into backlight
will turn your backlight off, etc...

Signed-off-by: Pavel Machek <pavel@...e.cz>

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index a013bbc..87d12a7 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -170,6 +170,8 @@ int strict_strtoul(const char *cp, unsig
 		return -EINVAL;
 
 	val = simple_strtoul(cp, &tail, base);
+	if (tail == cp)
+		return -EINVAL;
 	if ((*tail == '\0') ||
 		((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
 		*res = val;
@@ -241,6 +243,8 @@ int strict_strtoull(const char *cp, unsi
 		return -EINVAL;
 
 	val = simple_strtoull(cp, &tail, base);
+	if (tail == cp)
+		return -EINVAL;
 	if ((*tail == '\0') ||
 		((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
 		*res = val;

-- 
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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