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mm: Check if PUD is large when validating a kernel address

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This commit is contained in:
Justin M. Forbes 2013-02-14 11:35:13 -06:00
commit ec0018e745
3 changed files with 131 additions and 0 deletions
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15
kernel.spec
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@ -769,6 +769,10 @@ Patch21253: netback-correct-netbk_tx_err-to-handle-wrap-around.patch
#rhbz 906309 910848 CVE-2013-0228
Patch21254: xen-dont-assume-ds-is-usable-in-xen_iret-for-32-bit-PVOPS.patch
Patch23000: silence-brcmsmac-warning.patch
Patch23100: validate-pud-largepage.patch
#rhbz 909591
Patch21255: usb-cypress-supertop.patch
@ -1481,6 +1485,10 @@ ApplyPatch rtlwifi-Fix-scheduling-while-atomic-bug.patch
#rhbz 892811
ApplyPatch ath9k_rx_dma_stop_check.patch
ApplyPatch silence-brcmsmac-warning.patch
ApplyPatch validate-pud-largepage.patch
#rhbz 910886 CVE-2013-0216/CVE-2013-0217
ApplyPatch xen-netback-shutdown-the-ring-if-it-contains-garbage.patch
ApplyPatch xen-netback-don-t-leak-pages-on-failure-in-xen_netbk_tx_check_gop.patch
@ -2348,11 +2356,18 @@ fi
# '-' | |
# '-'
%changelog
* Thu Feb 14 2013 Josh Boyer <jwboyer@redhat.com>
- Add patch to fix corruption on newer M6116 SATA bridges (rhbz 909591)
- CVE-2013-0228 xen: xen_iret() invalid %ds local DoS (rhbz 910848 906309)
- CVE-2013-0216/0127 xen: netback DoS via malicious guest ring (rhbz 910886)
* Tue Feb 12 2013 Dave Jones <davej@redhat.com>
- mm: Check if PUD is large when validating a kernel address
* Tue Feb 12 2013 Dave Jones <davej@redhat.com>
- Silence brcmsmac warnings. (Fixed in 3.8, but not backporting to 3.7)
* Mon Feb 11 2013 Justin M. Forbes <jforbes@redhat.com> - 3.7.7-101
- Linux v3.7.7

14
silence-brcmsmac-warning.patch Normal file
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@ -0,0 +1,14 @@
This is fixed in 3.8, but is too much to backport for now.
As there's no point in abrt telling us this is broken, we'll just silence it.
--- linux-3.7.7-201.fc18.x86_64/drivers/net/wireless/brcm80211/brcmsmac/main.c~ 2013-02-12 11:36:18.787973130 -0500
+++ linux-3.7.7-201.fc18.x86_64/drivers/net/wireless/brcm80211/brcmsmac/main.c 2013-02-12 11:37:02.950969879 -0500
@@ -7993,8 +7993,6 @@ void brcms_c_wait_for_tx_completion(stru
if (--timeout == 0)
break;
}
-
- WARN_ON_ONCE(timeout == 0);
}
void brcms_c_set_beacon_listen_interval(struct brcms_c_info *wlc, u8 interval)

102
validate-pud-largepage.patch Normal file
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@ -0,0 +1,102 @@
Date: Mon, 11 Feb 2013 14:52:36 +0000
From: Mel Gorman <mgorman@suse.de>
To: Ingo Molnar <mingo@kernel.org>, Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH] x86: mm: Check if PUD is large when validating a kernel address
Message-ID: <20130211145236.GX21389@suse.de>
MIME-Version: 1.0
A user reported the following oops when a backup process read
/proc/kcore.
BUG: unable to handle kernel paging request at ffffbb00ff33b000
IP: [<ffffffff8103157e>] kern_addr_valid+0xbe/0x110
PGD 0
Oops: 0000 [#1] SMP
CPU 6
Modules linked in: af_packet nfs lockd fscache auth_rpcgss nfs_acl sunrpc 8021q garp stp llc cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf microcode fuse nls_iso8859_1 nls_cp437 vfat fat loop dm_mod ioatdma ipv6 ipv6_lib igb dca i7core_edac edac_core i2c_i801 i2c_core cdc_ether usbnet bnx2 mii iTCO_wdt iTCO_vendor_support shpchp rtc_cmos pci_hotplug tpm_tis sg tpm pcspkr tpm_bios serio_raw button ext3 jbd mbcache uhci_hcd ehci_hcd usbcore sd_mod crc_t10dif usb_common processor thermal_sys hwmon scsi_dh_emc scsi_dh_rdac scsi_dh_alua scsi_dh_hp_sw scsi_dh ata_generic ata_piix libata megaraid_sas scsi_mod
Pid: 16196, comm: Hibackp Not tainted 3.0.13-0.27-default #1 IBM System x3550 M3 -[7944 K3G]-/94Y7614
RIP: 0010:[<ffffffff8103157e>] [<ffffffff8103157e>] kern_addr_valid+0xbe/0x110
RSP: 0018:ffff88094165fe80 EFLAGS: 00010246
RAX: 00003300ff33b000 RBX: ffff880100000000 RCX: 0000000000000000
RDX: 0000000100000000 RSI: ffff880000000000 RDI: ff32b300ff33b400
RBP: 0000000000001000 R08: 00003ffffffff000 R09: 0000000000000000
R10: 22302e31223d6e6f R11: 0000000000000246 R12: 0000000000001000
R13: 0000000000003000 R14: 0000000000571be0 R15: ffff88094165ff50
FS: 00007ff152d33700(0000) GS:ffff88097f2c0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffffbb00ff33b000 CR3: 00000009405a3000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process Hibackp (pid: 16196, threadinfo ffff88094165e000, task ffff8808eb9ba600)
Stack:
ffffffff811b8aaa 0000000000004000 ffff880943fea480 ffff8808ef2bae50
ffff880943d32980 fffffffffffffffb ffff8808ef2bae40 ffff88094165ff50
0000000000004000 000000000056ebe0 ffffffff811ad847 000000000056ebe0
Call Trace:
[<ffffffff811b8aaa>] read_kcore+0x17a/0x370
[<ffffffff811ad847>] proc_reg_read+0x77/0xc0
[<ffffffff81151687>] vfs_read+0xc7/0x130
[<ffffffff811517f3>] sys_read+0x53/0xa0
[<ffffffff81449692>] system_call_fastpath+0x16/0x1b
Investigation determined that the bug triggered when reading system RAM
at the 4G mark. On this system, that was the first address using 1G pages
for the virt->phys direct mapping so the PUD is pointing to a physical
address, not a PMD page. The problem is that the page table walker in
kern_addr_valid() is not checking pud_large() and treats the physical
address as if it was a PMD. If it happens to look like pmd_none then it'll
silently fail, probably returning zeros instead of real data. If the data
happens to look like a present PMD though, it will be walked resulting in
the oops above. This patch adds the necessary pud_large() check.
Unfortunately the problem was not readily reproducible and now they are
running the backup program without accessing /proc/kcore so the patch has
not been validated but I think it makes sense. If reviewers agree then it
should also be included in -stable back as far as 3.0-stable.
Cc: stable@vger.kernel.org
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
arch/x86/include/asm/pgtable.h | 5 +++++
arch/x86/mm/init_64.c | 3 +++
2 files changed, 8 insertions(+)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 5199db2..1c1a955 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -142,6 +142,11 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
return (pmd_val(pmd) & PTE_PFN_MASK) >> PAGE_SHIFT;
}
+static inline unsigned long pud_pfn(pud_t pud)
+{
+ return (pud_val(pud) & PTE_PFN_MASK) >> PAGE_SHIFT;
+}
+
#define pte_page(pte) pfn_to_page(pte_pfn(pte))
static inline int pmd_large(pmd_t pte)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 2ead3c8..75c9a6a 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -831,6 +831,9 @@ int kern_addr_valid(unsigned long addr)
if (pud_none(*pud))
return 0;
+ if (pud_large(*pud))
+ return pfn_valid(pud_pfn(*pud));
+
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd))
return 0;
--
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