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authorLinus Torvalds <torvalds@g5.osdl.org>2006-06-28 17:09:34 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-28 17:09:34 -0700
commit0a6047eef1c465c38aacfbdab193161b3f0cd144 (patch)
tree3347213ad162a9570d6f4c5cffa1f8db7abb7cba
parent27d68a36c4f1ca2fc6be82620843493462c08c51 (diff)
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>
-rw-r--r--lib/vsprintf.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 797428afd11..bed7229378f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -489,7 +489,7 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
if (str < end)
*str = '\0';
else
- *end = '\0';
+ end[-1] = '\0';
}
/* the trailing null byte doesn't count towards the total */
return str-buf;