From 3bd7fa12e146c6051490d048a4acbfba974eeb04 Mon Sep 17 00:00:00 2001 From: Christian Brabandt Date: Mon, 2 Oct 2023 20:59:08 +0200 Subject: [PATCH 2156/2205] patch 9.0.1969: [security] buffer-overflow in trunc_string() Problem: buffer-overflow in trunc_string() Solution: Add NULL at end of buffer Currently trunc_string() assumes that when the string is too long, buf[e-1] will always be writeable. But that assumption may not always be true. The condition currently looks like this else if (e + 3 < buflen) [...] else { // can't fit in the "...", just truncate it buf[e - 1] = NUL; } but this means, we may run into the last else clause with e still being larger than buflen. So a buffer overflow occurs. So instead of using `buf[e - 1]`, let's just always truncate at `buf[buflen - 1]` which should always be writable. Signed-off-by: Christian Brabandt --- src/message.c | 2 +- 1 files changed, 1 insertions(+), 1 deletion(-) diff --git a/src/message.c b/src/message.c index 2fc6cefa9..83c8b4f4a 100644 --- a/src/message.c +++ b/src/message.c @@ -349,7 +349,7 @@ trunc_string( else { // can't fit in the "...", just truncate it - buf[e - 1] = NUL; + buf[buflen - 1] = NUL; } } -- 2.27.0