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authorGleb Natapov <gleb@redhat.com>2011-03-07 14:55:07 +0200
committerMarcelo Tosatti <mtosatti@redhat.com>2011-03-17 13:08:33 -0300
commit399a40c92d744feebf89b1f07208407c26e0aaf5 (patch)
tree69ae89dacff4378ec621bffc2fb06b71ca86bda7
parent5601d05b8c340ee2643febc146099325eff187eb (diff)
downloadlinux-399a40c92d744feebf89b1f07208407c26e0aaf5.tar.bz2
KVM: emulator: Fix permission checking in io permission bitmap
Currently if io port + len crosses 8bit boundary in io permission bitmap the check may allow IO that otherwise should not be allowed. The patch fixes that. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
-rw-r--r--arch/x86/kvm/emulate.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d6088b8686fb..0ad47b819a8b 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1769,8 +1769,7 @@ static bool emulator_io_port_access_allowed(struct x86_emulate_ctxt *ctxt,
struct desc_struct tr_seg;
u32 base3;
int r;
- u16 io_bitmap_ptr;
- u8 perm, bit_idx = port & 0x7;
+ u16 io_bitmap_ptr, perm, bit_idx = port & 0x7;
unsigned mask = (1 << len) - 1;
unsigned long base;
@@ -1788,7 +1787,7 @@ static bool emulator_io_port_access_allowed(struct x86_emulate_ctxt *ctxt,
return false;
if (io_bitmap_ptr + port/8 > desc_limit_scaled(&tr_seg))
return false;
- r = ops->read_std(base + io_bitmap_ptr + port/8, &perm, 1, ctxt->vcpu,
+ r = ops->read_std(base + io_bitmap_ptr + port/8, &perm, 2, ctxt->vcpu,
NULL);
if (r != X86EMUL_CONTINUE)
return false;