From c8f0723d2b4520bdd6b9eb7c3e7976de726d7ff7 Mon Sep 17 00:00:00 2001 From: Hanno Boeck Date: Wed, 27 Jan 2016 15:10:11 +0100 Subject: Fix heap buffer overflow in fgetwln() In the function fgetwln() there's a 4 byte heap overflow. There is a while loop that has this check to see whether there's still enough space in the buffer: if (!fb->len || wused > fb->len) { If this is true more memory gets allocated. However this test won't be true if wused == fb->len, but at that point wused already points out of the buffer. Some lines later there's a write to the buffer: fb->wbuf[wused++] = wc; This bug was found with the help of address sanitizer. Warned-by: ASAN Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=93881 Signed-off-by: Guillem Jover --- src/fgetwln.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/fgetwln.c b/src/fgetwln.c index 9ee0776..aa3f927 100644 --- a/src/fgetwln.c +++ b/src/fgetwln.c @@ -60,7 +60,7 @@ fgetwln(FILE *stream, size_t *lenp) fb->fp = stream; while ((wc = fgetwc(stream)) != WEOF) { - if (!fb->len || wused > fb->len) { + if (!fb->len || wused >= fb->len) { wchar_t *wp; if (fb->len) -- cgit v1.2.3