[Xen-changelog] [xen stable-4.2] x86/HVM: return all ones on wrong-sized reads of system device I/O ports

[patchbot@xxxxxxx]

commit 0765915d3a11ebf56d89da58b346c9b85ca3299d
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Mar 5 13:50:50 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Mar 5 13:50:50 2015 +0100

    x86/HVM: return all ones on wrong-sized reads of system device I/O ports
    
    So far the value presented to the guest remained uninitialized.
    
    This is CVE-2015-2044 / XSA-121.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    master commit: c9e57594e1ba5da9d705dee9f00aa4e7e925963d
    master date: 2015-03-05 13:34:54 +0100
---
 xen/arch/x86/hvm/i8254.c   |    1 +
 xen/arch/x86/hvm/pmtimer.c |    1 +
 xen/arch/x86/hvm/rtc.c     |    3 ++-
 xen/arch/x86/hvm/vpic.c    |    1 +
 4 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/xen/arch/x86/hvm/i8254.c b/xen/arch/x86/hvm/i8254.c
index c0d6bc2..809d09e 100644
--- a/xen/arch/x86/hvm/i8254.c
+++ b/xen/arch/x86/hvm/i8254.c
@@ -478,6 +478,7 @@ static int handle_pit_io(
     if ( bytes != 1 )
     {
         gdprintk(XENLOG_WARNING, "PIT bad access\n");
+        *val = ~0;
         return X86EMUL_OKAY;
     }
 
diff --git a/xen/arch/x86/hvm/pmtimer.c b/xen/arch/x86/hvm/pmtimer.c
index 01ae31d..6ad2797 100644
--- a/xen/arch/x86/hvm/pmtimer.c
+++ b/xen/arch/x86/hvm/pmtimer.c
@@ -213,6 +213,7 @@ static int handle_pmt_io(
     if ( bytes != 4 )
     {
         gdprintk(XENLOG_WARNING, "HVM_PMT bad access\n");
+        *val = ~0;
         return X86EMUL_OKAY;
     }
     
diff --git a/xen/arch/x86/hvm/rtc.c b/xen/arch/x86/hvm/rtc.c
index b994e99..0a648d1 100644
--- a/xen/arch/x86/hvm/rtc.c
+++ b/xen/arch/x86/hvm/rtc.c
@@ -619,7 +619,8 @@ static int handle_rtc_io(
 
     if ( bytes != 1 )
     {
-        gdprintk(XENLOG_WARNING, "HVM_RTC bas access\n");
+        gdprintk(XENLOG_WARNING, "HVM_RTC bad access\n");
+        *val = ~0;
         return X86EMUL_OKAY;
     }
     
diff --git a/xen/arch/x86/hvm/vpic.c b/xen/arch/x86/hvm/vpic.c
index fea3f68..6e4d422 100644
--- a/xen/arch/x86/hvm/vpic.c
+++ b/xen/arch/x86/hvm/vpic.c
@@ -324,6 +324,7 @@ static int vpic_intercept_pic_io(
     if ( bytes != 1 )
     {
         gdprintk(XENLOG_WARNING, "PIC_IO bad access size %d\n", bytes);
+        *val = ~0;
         return X86EMUL_OKAY;
     }
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.2

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