Re: [PATCH v1 2/3] MdeModulePkg/PciBusDxe: Fix possible uninitialized use


Wu, Hao A
 

-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Sergei
Dmitrouk
Sent: Tuesday, May 18, 2021 12:23 AM
To: devel@edk2.groups.io; Ni, Ray <ray.ni@...>
Cc: Wang, Jian J <jian.j.wang@...>; Wu, Hao A <hao.a.wu@...>
Subject: Re: [edk2-devel] [PATCH v1 2/3] MdeModulePkg/PciBusDxe: Fix
possible uninitialized use

If the function gets invalid value for the `ResizableBarOp` parameter and
asserts are disabled, `Bit` can be used uninitialized.

Cc: Jian J Wang <jian.j.wang@...>
Cc: Hao A Wu <hao.a.wu@...>
Cc: Ray Ni <ray.ni@...>
Signed-off-by: Sergei Dmitrouk <sergei@...>
---

Notes:
v2:
- simplify if-statement to avoid unused branches

Hello,

Since the V1 is a patch series, I would suggest to send the whole series for V2 changes (even if other patches are unchanged).

With this handled:
Reviewed-by: Hao A Wu <hao.a.wu@...>

Best Regards,
Hao Wu


MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
index 6bba28367165..4caac56f1dcd 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
@@ -1778,10 +1778,9 @@ PciProgramResizableBar (

if (ResizableBarOp == PciResizableBarMax) {
Bit = HighBitSet64(Capabilities);
- } else if (ResizableBarOp == PciResizableBarMin) {
+ } else {
+ ASSERT (ResizableBarOp == PciResizableBarMin);
Bit = LowBitSet64(Capabilities);
- } else {
- ASSERT ((ResizableBarOp == PciResizableBarMax) || (ResizableBarOp ==
PciResizableBarMin));
}

ASSERT (Bit >= 0);
--
2.17.6




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