GNU bug report logs - #78879
Potential Out-of-Memory in coreutils od

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Message #8 received at 78879 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Jaehoon Jang <jaehoon.jang <at> prosys.kaist.ac.kr>, 78879 <at> debbugs.gnu.org
Subject: Re: bug#78879: Potential Out-of-Memory in coreutils od
Date: Tue, 24 Jun 2025 01:08:03 -0700

On 2025-06-23 01:21, Jaehoon Jang wrote:
> This happens because the parsed -w value is passed to bytes_per_block,
> which is then used in a call to xnmalloc, leading to potentially dangerous
> memory allocation.

"Dangerous" in the sense that if you give "od" a large task it needs a 
lot of RAM? If so, most nontrivial programs are "dangerous".


> To mitigate this issue, we suggest adding a proper argument validation
> check to handle such edge cases safely.

No need for that. Just use 'ulimit -v' and set whatever limit you like. 
This will fix the danger that you perceive, not just for "od", but for 
all applications that you run. There's no need to change the apps.

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