[PR PATCH] Fix Out-of-Bounds Array Access in parse_parent

[PR PATCH] Fix Out-of-Bounds Array Access in parse_parent

[R3x]

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There is a new pull request by R3x against master on the mblaze repository

https://github.com/R3x/mblaze R3x-patch-1
https://github.com/leahneukirchen/mblaze/pull/269

Fix Out-of-Bounds Array Access in parse_parent
Hello, submitting a patch to a Out-of-Bounds Array Access that I found. 

If the case `while (*s && iswsp(*s)) {`  is not satisfied, the value of the variable `ident` remains 0. 
This will make the access `previndent[ident - 1]` to `previndent[-1]` which will lead to undefined behaviour.

The patch adds a check before the call. 

A patch file from https://github.com/leahneukirchen/mblaze/pull/269.patch is attached

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From 70f0548a256240465f4c9caa29e861861bc86af2 Mon Sep 17 00:00:00 2001
From: Siddharth M <siddharth.muralee@gmail.com>
Date: Sun, 6 Apr 2025 21:56:04 -0400
Subject: [PATCH] Fix bug in seq.c

---
 seq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/seq.c b/seq.c
index 5d982846..e5fa0b17 100644
--- a/seq.c
+++ b/seq.c
@@ -326,7 +326,7 @@ parse_parent(char *map, long *starto, long *stopo)
 			indent = 255;
 		previndent[indent] = line;
 		if (line == *starto) {
-			if (previndent[indent-1]) {
+			if (indent > 0 && previndent[indent-1]) {
 				*starto = *stopo = previndent[indent-1];
 				return 0;
 			} else {

Re: [PR PATCH] [Closed]: Fix Out-of-Bounds Array Access in parse_parent

[leahneukirchen]

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There's a closed pull request on the mblaze repository

Fix Out-of-Bounds Array Access in parse_parent
https://github.com/leahneukirchen/mblaze/pull/269

Description:
Hello, submitting a patch to a Out-of-Bounds Array Access that I found. 

If the case `while (*s && iswsp(*s)) {`  is not satisfied, the value of the variable `ident` remains 0. 
This will make the access `previndent[ident - 1]` to `previndent[-1]` which will lead to undefined behaviour.

The patch adds a check before the call. 

Re: Fix Out-of-Bounds Array Access in parse_parent

[leahneukirchen]

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New comment by leahneukirchen on mblaze repository

https://github.com/leahneukirchen/mblaze/pull/269#issuecomment-2782804111

Comment:
Thanks, closed in 261fa34.