From: Randy Dunlap <rdunlap@infradead.org>
To: Entropy Moe <3ntr0py1337@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, Dmitry Vyukov <dvyukov@google.com>
Subject: Re: KASAN: stack-out-of-bounds Write in mpol_to_str
Date: Wed, 25 Mar 2020 17:54:48 -0700 [thread overview]
Message-ID: <110bb9ab-9765-1c5b-39c6-3644cb1b99a4@infradead.org> (raw)
In-Reply-To: <CALzBtj+8AYASaYW2fqgmgthCgeAJ2N0Q+ey2wqgEKjBtH34Vcg@mail.gmail.com>
On 3/20/20 1:36 AM, Entropy Moe wrote:
> Hello Randy,
> please see attached POC for the vulnerability.
>
Hi Moe,
Do you have anything to do with the syzkaller source code generation? (POC; reproducers)
I don't expect it to be beautiful, but it could be a lot easier to read in a few places.
E.g., the POC that you provided sets a tmpfs mount option string to
"mpol=prefer:,", which is probably purposely malformed (OK), but it does
so in an unreadable manner: (I added the // comments.)
memcpy((void*)0x20000340, "mpol", 4);
*(uint8_t*)0x20000344 = 0x3d; // =
memcpy((void*)0x20000345, "prefer", 6);
*(uint8_t*)0x2000034b = 0x3a; // :
*(uint8_t*)0x2000034c = 0x2c; // ,
*(uint8_t*)0x2000034d = 0;
That kind of obfuscation just helps slow down debugging. :(
--
~Randy
next prev parent reply other threads:[~2020-03-26 0:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-15 19:57 KASAN: stack-out-of-bounds Write in mpol_to_str Entropy Moe
2020-03-16 18:46 ` Randy Dunlap
2020-03-20 8:36 ` Entropy Moe
2020-03-21 6:45 ` Andrew Morton
2020-03-26 0:54 ` Randy Dunlap [this message]
2020-03-26 0:45 ` [PATCH] mm: mempolicy: require at least one nodeid for MPOL_PREFERRED Randy Dunlap
2020-03-26 2:23 KASAN: stack-out-of-bounds Write in mpol_to_str syzbot
2020-03-26 3:47 ` Randy Dunlap
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