Fix vsnprintf off-by-one bug
The recent vsnprintf() fix introduced an off-by-one, and it's now
possible to overrun the target buffer by one byte.
The "end" pointer points to past the end of the buffer, so if we
have to truncate the result, it needs to be done though "end[-1]".
[ This is just an alternate and simpler patch to one proposed by Andrew
and Jeremy, who actually noticed the problem ]
Acked-by: Andrew Morton <akpm@osdl.org>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 797428a..bed7229 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -489,7 +489,7 @@
if (str < end)
*str = '\0';
else
- *end = '\0';
+ end[-1] = '\0';
}
/* the trailing null byte doesn't count towards the total */
return str-buf;