From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
Nadav Amit <nadav.amit@gmail.com>,
Kees Cook <keescook@chromium.org>,
Brian Gerst <brgerst@gmail.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v4 04/16] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated
Date: Thu, 23 Jun 2016 21:22:59 -0700 [thread overview]
Message-ID: <3403d1d7d13c5a28635507c5e47400800ddc3733.1466741835.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1466741835.git.luto@kernel.org>
In-Reply-To: <cover.1466741835.git.luto@kernel.org>
This avoids pointless races in which another CPU or task might see a
partially populated global pgd entry. These races should normally
be harmless, but, if another CPU propagates the entry via
vmalloc_fault and then populate_pgd fails (due to memory allocation
failure, for example), this prevents a use-after-free of the pgd
entry.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/mm/pageattr.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 7a1f7bbf4105..6a8026918bf6 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1113,7 +1113,9 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr)
ret = populate_pud(cpa, addr, pgd_entry, pgprot);
if (ret < 0) {
- unmap_pgd_range(cpa->pgd, addr,
+ if (pud)
+ free_page((unsigned long)pud);
+ unmap_pud_range(pgd_entry, addr,
addr + (cpa->numpages << PAGE_SHIFT));
return ret;
}
--
2.5.5
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
Nadav Amit <nadav.amit@gmail.com>,
Kees Cook <keescook@chromium.org>,
Brian Gerst <brgerst@gmail.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [kernel-hardening] [PATCH v4 04/16] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated
Date: Thu, 23 Jun 2016 21:22:59 -0700 [thread overview]
Message-ID: <3403d1d7d13c5a28635507c5e47400800ddc3733.1466741835.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1466741835.git.luto@kernel.org>
In-Reply-To: <cover.1466741835.git.luto@kernel.org>
This avoids pointless races in which another CPU or task might see a
partially populated global pgd entry. These races should normally
be harmless, but, if another CPU propagates the entry via
vmalloc_fault and then populate_pgd fails (due to memory allocation
failure, for example), this prevents a use-after-free of the pgd
entry.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/mm/pageattr.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 7a1f7bbf4105..6a8026918bf6 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1113,7 +1113,9 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr)
ret = populate_pud(cpa, addr, pgd_entry, pgprot);
if (ret < 0) {
- unmap_pgd_range(cpa->pgd, addr,
+ if (pud)
+ free_page((unsigned long)pud);
+ unmap_pud_range(pgd_entry, addr,
addr + (cpa->numpages << PAGE_SHIFT));
return ret;
}
--
2.5.5
next prev parent reply other threads:[~2016-06-24 4:27 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-24 4:22 [PATCH v4 00/16] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski
2016-06-24 4:22 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:22 ` Andy Lutomirski
2016-06-24 4:22 ` [PATCH v4 01/16] bluetooth: Switch SMP to crypto_cipher_encrypt_one() Andy Lutomirski
2016-06-24 4:22 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:22 ` Andy Lutomirski
2016-06-24 6:10 ` Herbert Xu
2016-06-24 6:10 ` [kernel-hardening] " Herbert Xu
2016-06-24 6:10 ` Herbert Xu
2016-06-24 7:19 ` Johan Hedberg
2016-06-24 7:19 ` [kernel-hardening] " Johan Hedberg
2016-06-24 7:19 ` Johan Hedberg
2016-06-24 4:22 ` [PATCH v4 02/16] rxrpc: Avoid using stack memory in SG lists in rxkad Andy Lutomirski
2016-06-24 4:22 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:22 ` Andy Lutomirski
2016-06-24 4:22 ` [PATCH v4 03/16] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski
2016-06-24 4:22 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:22 ` Andy Lutomirski
2016-06-24 4:22 ` Andy Lutomirski
2016-06-24 4:22 ` Andy Lutomirski [this message]
2016-06-24 4:22 ` [kernel-hardening] [PATCH v4 04/16] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski
2016-06-24 4:22 ` Andy Lutomirski
2016-06-24 4:23 ` [PATCH v4 05/16] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 4:23 ` [PATCH v4 06/16] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 15:21 ` Josh Poimboeuf
2016-06-24 15:21 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 15:21 ` Josh Poimboeuf
2016-06-24 15:21 ` Josh Poimboeuf
2016-06-24 4:23 ` [PATCH v4 07/16] mm: Fix memcg stack accounting for sub-page stacks Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 15:22 ` Josh Poimboeuf
2016-06-24 15:22 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 15:22 ` Josh Poimboeuf
2016-06-24 15:22 ` Josh Poimboeuf
2016-06-24 4:23 ` [PATCH v4 08/16] dma-api: Teach the "DMA-from-stack" check about vmapped stacks Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 4:23 ` [PATCH v4 09/16] fork: Add generic vmalloced stack support Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 4:23 ` [PATCH v4 10/16] x86/die: Don't try to recover from an OOPS on a non-default stack Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 4:23 ` [PATCH v4 11/16] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 15:30 ` Josh Poimboeuf
2016-06-24 15:30 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 15:30 ` Josh Poimboeuf
2016-06-24 15:35 ` Brian Gerst
2016-06-24 15:35 ` [kernel-hardening] " Brian Gerst
2016-06-24 15:35 ` Brian Gerst
2016-06-24 15:48 ` Josh Poimboeuf
2016-06-24 15:48 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 15:48 ` Josh Poimboeuf
2016-06-24 4:23 ` [PATCH v4 12/16] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 15:31 ` Josh Poimboeuf
2016-06-24 15:31 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 15:31 ` Josh Poimboeuf
2016-06-24 4:23 ` [PATCH v4 13/16] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 15:35 ` Josh Poimboeuf
2016-06-24 15:35 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 15:35 ` Josh Poimboeuf
2016-06-26 16:59 ` Andy Lutomirski
2016-06-26 16:59 ` [kernel-hardening] " Andy Lutomirski
2016-06-26 16:59 ` Andy Lutomirski
2016-06-24 4:23 ` [PATCH v4 14/16] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 15:36 ` Josh Poimboeuf
2016-06-24 15:36 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 15:36 ` Josh Poimboeuf
2016-06-24 4:23 ` [PATCH v4 15/16] x86/mm/64: Enable vmapped stacks Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
2016-06-24 4:23 ` [PATCH v4 16/16] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski
2016-06-24 4:23 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 4:23 ` Andy Lutomirski
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