From: Corinna Vinschen <vinschen@redhat.com>
To: newlib@sourceware.org
Cc: Cyril Yared <yaredcyril@gmail.com>
Subject: Re: Null-pointer dereference bug in nano-malloc
Date: Tue, 25 Jan 2022 13:35:08 +0100 [thread overview]
Message-ID: <Ye/ufG4G1kqASYhd@calimero.vinschen.de> (raw)
In-Reply-To: <CAFq0=_MsCp0=AaHENtW=idrD4Z=PYX40ybJnyY85_qZ4urdN0g@mail.gmail.com>
On Jan 24 22:04, Cyril Yared wrote:
> Hi,
> It appears that commit 84d068971 introduced a null-pointer dereference in
> nano-malloc when the following two conditions are met:
>
> 1). The free_list has no items (= NULL).
> 2). The call to sbrk_aligned returns -1 (failure).
>
> On line 325 of newlib/libc/stdlib/nano-mallocr.c, there is a check:
>
> if ((char *)p + p->size == (char *)_SBRK_R(RCALL 0))
> {
>
> If the two conditions are met, then p = free_list = NULL so p->size will be
> a null-pointer dereference. Is this something that's known/being tracked
> anywhere?
I don't think so. Just send a patch, please.
Corinna
prev parent reply other threads:[~2022-01-25 12:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-25 6:04 Cyril Yared
2022-01-25 12:35 ` Corinna Vinschen [this message]
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