Re: [Qemu-devel] [PATCH RFC 1 3/8] xen/pt: Check if reg-init is past the reg-size

[Stefano Stabellini]

On Mon, 29 Jun 2015, Konrad Rzeszutek Wilk wrote:
 It should never happen, but in case it does we want to
 report. The code will only write up to reg-size so there
 is no runtime danger.
 
 Signed-off-by: Konrad Rzeszutek Wilk konrad.w...@oracle.com
 ---
  hw/xen/xen_pt_config_init.c | 8 ++--
  1 file changed, 6 insertions(+), 2 deletions(-)
 
 diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
 index 91c3a14..bc871c9 100644
 --- a/hw/xen/xen_pt_config_init.c
 +++ b/hw/xen/xen_pt_config_init.c
 @@ -1901,9 +1901,13 @@ static int 
 xen_pt_config_reg_init(XenPCIPassthroughState *s,
  } else
  val = data;
  
 +if (val  size_mask) {
 +XEN_PT_ERR(s-dev,Offset 0x%04x:0x%04u expands past register 
 size(%d)!\n,
 +   offset, val, reg-size);

should we return early?


 +}
  /* This could be just pci_set_long as we don't modify the bits
 - * past reg-size, but in case this routine is run in parallel
 - * we do not want to over-write other registers. */
 + * past reg-size, but in case this routine is run in parallel or the
 + * init value is larger, we do not want to over-write registers. */
  switch (reg-size) {
  case 1: pci_set_byte(s-dev.config + offset, (uint8_t)val); break;
  case 2: pci_set_word(s-dev.config + offset, (uint16_t)val); break;
 -- 
 2.1.0
 

[Qemu-devel] [PATCH RFC 1 3/8] xen/pt: Check if reg-init is past the reg-size

[Konrad Rzeszutek Wilk]

It should never happen, but in case it does we want to
report. The code will only write up to reg-size so there
is no runtime danger.

Signed-off-by: Konrad Rzeszutek Wilk konrad.w...@oracle.com
---
 hw/xen/xen_pt_config_init.c | 8 ++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index 91c3a14..bc871c9 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -1901,9 +1901,13 @@ static int xen_pt_config_reg_init(XenPCIPassthroughState 
*s,
 } else
 val = data;
 
+if (val  size_mask) {
+XEN_PT_ERR(s-dev,Offset 0x%04x:0x%04u expands past register 
size(%d)!\n,
+   offset, val, reg-size);
+}
 /* This could be just pci_set_long as we don't modify the bits
- * past reg-size, but in case this routine is run in parallel
- * we do not want to over-write other registers. */
+ * past reg-size, but in case this routine is run in parallel or the
+ * init value is larger, we do not want to over-write registers. */
 switch (reg-size) {
 case 1: pci_set_byte(s-dev.config + offset, (uint8_t)val); break;
 case 2: pci_set_word(s-dev.config + offset, (uint16_t)val); break;
-- 
2.1.0