From: Florian Weimer <fw@deneb.enyo.de>
To: Xi Ruoyao <xry111@mengyan1223.wang>
Cc: Jonny Grant <jg@jguk.org>, gcc-help <gcc-help@gcc.gnu.org>
Subject: Re: Recursive SIGSEGV question
Date: Mon, 25 Mar 2019 15:47:00 -0000 [thread overview]
Message-ID: <87ef6vkq8a.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <d3e73ef74c12829b7c827434bdebd8cfe0247c60.camel@mengyan1223.wang> (Xi Ruoyao's message of "Mon, 25 Mar 2019 21:55:56 +0800")
* Xi Ruoyao:
> On 2019-03-25 13:06 +0000, Jonny Grant wrote:
>>
>> I built & ran with the Sanitizer, it seems it's also stack overflow
>> within the operator new()
>>
>> I had thoughts GCC would generate code that monitored the stack size and
>> aborted with a clear message when the stack size was exceeded. Looked
>> online, and it doesn't seem to be the case.
>
> Impossible. We can't distinguish "stack overflow" with other segmentation
> faults.
I think “impossible” is too strong.
It would be possible to annotate implicit probes and explicit probes
generated by -fstack-clash-protection in DWARF, and use that
information to generate a more precise error message.
Or we could set a bit on the guard page that instructs the kernel to
report an additional fault flag somewhere in siginfo_t. In fact, with
protection keys, we could do this today, without any kernel changes
whatsoever (but protection flags are not widely supported,
unfortunately).
The second approach will have false positives, but as buffer overflows
tend to proceed towards higher addresses and stacks grow downward,
only really bogus pointers would be misreported (and once you have
those, all bets are off anyway).
next prev parent reply other threads:[~2019-03-25 14:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-19 22:05 Jonny Grant
2019-03-20 4:02 ` Florian Weimer
2019-03-20 8:11 ` Jonny Grant
2019-03-25 13:23 ` Jonny Grant
2019-03-25 13:27 ` Jonathan Wakely
2019-03-25 13:56 ` Florian Weimer
2019-03-25 14:01 ` Xi Ruoyao
2019-03-25 15:47 ` Florian Weimer [this message]
2019-03-25 16:10 ` Andrew Haley
2019-03-25 16:13 ` Jonny Grant
2019-03-25 16:23 ` Jonathan Wakely
2019-03-25 18:51 ` Florian Weimer
2019-03-25 20:39 ` Jonny Grant
2019-03-26 6:50 ` Xi Ruoyao
2019-03-27 0:29 ` Jonathan Wakely
2019-03-27 21:34 ` Jonny Grant
2019-03-27 23:43 ` Jonathan Wakely
2019-03-27 23:51 ` Jonny Grant
2019-03-28 8:26 ` Xi Ruoyao
2019-03-28 11:52 ` Jonathan Wakely
2019-03-29 2:24 ` Jonny Grant
2019-03-30 17:32 ` Jonny Grant
2023-02-19 21:21 ` Jonny Grant
2023-02-19 21:34 ` Jonny Grant
2019-03-28 13:55 ` Jonathan Wakely
2019-03-28 14:39 ` Jonny Grant
2019-03-28 14:39 ` Jonathan Wakely
2019-03-25 20:28 ` Segher Boessenkool
2019-03-25 18:56 ` Segher Boessenkool
2019-03-25 22:05 ` Jonny Grant
2019-03-26 10:20 ` Xi Ruoyao
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