linux-kernel - [PATCH 4.18 227/228] powerpc/pkeys: Fix reading of ibm, processor-storage-keys property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181002132512.712182289@linuxfoundation.org>
Date:   Tue,  2 Oct 2018 06:25:24 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.18 227/228] powerpc/pkeys: Fix reading of ibm, processor-storage-keys property

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thiago Jung Bauermann <bauerman@...ux.ibm.com>

commit c716a25b9b70084e1144f77423f5aedd772ea478 upstream.

scan_pkey_feature() uses of_property_read_u32_array() to read the
ibm,processor-storage-keys property and calls be32_to_cpu() on the
value it gets. The problem is that of_property_read_u32_array() already
returns the value converted to the CPU byte order.

The value of pkeys_total ends up more or less sane because there's a min()
call in pkey_initialize() which reduces pkeys_total to 32. So in practice
the kernel ignores the fact that the hypervisor reserved one key for
itself (the device tree advertises 31 keys in my test VM).

This is wrong, but the effect in practice is that when a process tries to
allocate the 32nd key, it gets an -EINVAL error instead of -ENOSPC which
would indicate that there aren't any keys available

Fixes: cf43d3b26452 ("powerpc: Enable pkey subsystem")
Cc: stable@...r.kernel.org # v4.16+
Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/mm/pkeys.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -44,7 +44,7 @@ static void scan_pkey_feature(void)
 	 * Since any pkey can be used for data or execute, we will just treat
 	 * all keys as equal and track them as one entity.
 	 */
-	pkeys_total = be32_to_cpu(vals[0]);
+	pkeys_total = vals[0];
 	pkeys_devtree_defined = true;
 }