From: Borislav Petkov <bp@suse.de>
To: "Chang S. Bae" <chang.seok.bae@intel.com>
Cc: tglx@linutronix.de, mingo@kernel.org, luto@kernel.org,
x86@kernel.org, len.brown@intel.com, dave.hansen@intel.com,
hjl.tools@gmail.com, Dave.Martin@arm.com, jannh@google.com,
mpe@ellerman.id.au, carlos@redhat.com, tony.luck@intel.com,
ravi.v.shankar@intel.com, libc-alpha@sourceware.org,
linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 5/6] x86/signal: Detect and prevent an alternate signal stack overflow
Date: Tue, 16 Mar 2021 12:52:48 +0100 [thread overview]
Message-ID: <20210316115248.GB18822@zn.tnic> (raw)
In-Reply-To: <20210316065215.23768-6-chang.seok.bae@intel.com>
On Mon, Mar 15, 2021 at 11:52:14PM -0700, Chang S. Bae wrote:
> @@ -272,7 +275,8 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
> * If we are on the alternate signal stack and would overflow it, don't.
> * Return an always-bogus address instead so we will die with SIGSEGV.
> */
> - if (onsigstack && !likely(on_sig_stack(sp)))
> + if (onsigstack && unlikely(sp <= current->sas_ss_sp ||
> + sp - current->sas_ss_sp > current->sas_ss_size))
> return (void __user *)-1L;
So clearly I'm missing something because trying to trigger the test case
in the bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=153531
on current tip/master doesn't work. Runs with MY_MINSIGSTKSZ under 2048
fail with:
tst-minsigstksz-2: sigaltstack: Cannot allocate memory
and above 2048 don't overwrite bytes below the stack.
So something else is missing. How did you test this patch?
Thx.
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
next prev parent reply other threads:[~2021-03-16 11:53 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 6:52 [PATCH v7 0/6] x86: Improve Minimum Alternate Stack Size Chang S. Bae
2021-03-16 6:52 ` [PATCH v7 1/6] uapi: Define the aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-03-16 6:52 ` Chang S. Bae
2021-03-16 6:52 ` [PATCH v7 2/6] x86/signal: Introduce helpers to get the maximum signal frame size Chang S. Bae
2021-03-16 6:52 ` [PATCH v7 3/6] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-03-16 6:52 ` [PATCH v7 4/6] selftest/sigaltstack: Use the AT_MINSIGSTKSZ aux vector if available Chang S. Bae
2021-03-16 6:52 ` [PATCH v7 5/6] x86/signal: Detect and prevent an alternate signal stack overflow Chang S. Bae
2021-03-16 11:52 ` Borislav Petkov [this message]
2021-03-16 18:26 ` Bae, Chang Seok
2021-03-25 16:20 ` Borislav Petkov
2021-03-25 17:21 ` Bae, Chang Seok
2021-03-25 20:14 ` Florian Weimer
2021-03-25 18:13 ` Andy Lutomirski
2021-03-25 18:54 ` Borislav Petkov
2021-03-25 21:11 ` Bae, Chang Seok
2021-03-25 21:27 ` Borislav Petkov
2021-03-26 4:56 ` Andy Lutomirski
2021-03-26 10:30 ` Borislav Petkov
2021-04-12 22:30 ` Bae, Chang Seok
2021-04-14 10:12 ` Borislav Petkov
2021-04-14 11:30 ` Florian Weimer
2021-04-14 12:06 ` Borislav Petkov
2021-05-03 5:30 ` Florian Weimer
2021-05-03 11:17 ` Borislav Petkov
2021-03-26 4:58 ` Andy Lutomirski
2021-03-16 6:52 ` [PATCH v7 6/6] selftest/x86/signal: Include test cases for validating sigaltstack Chang S. Bae
2021-03-17 10:06 ` [PATCH v7 0/6] x86: Improve Minimum Alternate Stack Size Ingo Molnar
2021-03-17 10:44 ` Ingo Molnar
2021-03-19 18:12 ` Len Brown
2021-03-20 17:32 ` Ingo Molnar
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