[3.19.y-ckt stable] Patch "arm64: cpuinfo: Missing NULL terminator in compat_hwcap_str" has been added to the 3.19.y-ckt tree

Kamal Mostafa kamal at canonical.com
Wed Jul 6 21:00:46 UTC 2016


This is a note to let you know that I have just added a patch titled

    arm64: cpuinfo: Missing NULL terminator in compat_hwcap_str

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt23.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From e72aede44c49d14e4eb8bdc08175472b5decae86 Mon Sep 17 00:00:00 2001
From: Julien Grall <julien.grall at arm.com>
Date: Tue, 10 May 2016 15:40:31 +0100
Subject: arm64: cpuinfo: Missing NULL terminator in compat_hwcap_str

commit f228b494e56d949be8d8ea09d4f973d1979201bf upstream.

The loop that browses the array compat_hwcap_str will stop when a NULL
is encountered, however NULL is missing at the end of array. This will
lead to overrun until a NULL is found somewhere in the following memory.
In reality, this works out because the compat_hwcap2_str array tends to
follow immediately in memory, and that *is* terminated correctly.
Furthermore, the unsigned int compat_elf_hwcap is checked before
printing each capability, so we end up doing the right thing because
the size of the two arrays is less than 32. Still, this is an obvious
mistake and should be fixed.

Note for backporting: commit 12d11817eaafa414 ("arm64: Move
/proc/cpuinfo handling code") moved this code in v4.4. Prior to that
commit, the same change should be made in arch/arm64/kernel/setup.c.

Fixes: 44b82b7700d0 "arm64: Fix up /proc/cpuinfo"
Signed-off-by: Julien Grall <julien.grall at arm.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
[ kamal: backport to 4.2-stable: applied to setup.c ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/arm64/kernel/setup.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 386acb8..07df3f7 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -491,7 +491,8 @@ static const char *compat_hwcap_str[] = {
 	"idivt",
 	"vfpd32",
 	"lpae",
-	"evtstrm"
+	"evtstrm",
+	NULL
 };

 static const char *compat_hwcap2_str[] = {
--
2.7.4





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