Laszlo Ersek
c2f643479e
OvmfPkg/BasePciCapLib: suppress invalid "nullptr deref" warning
...
RH covscan reports the following "nullptr deref" warning:
> Error: CLANG_WARNING:
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:312:5:
> warning: Dereference of null pointer
> # InstanceZero->NumInstancesUnion.NumInstances++;
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:509:7:
> note: Assuming 'OutCapList' is not equal to NULL
> # if (OutCapList == NULL) {
> # ^~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:509:3:
> note: Taking false branch
> # if (OutCapList == NULL) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:518:7:
> note: Assuming the condition is false
> # if (OutCapList->Capabilities == NULL) {
> # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:518:3:
> note: Taking false branch
> # if (OutCapList->Capabilities == NULL) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:529:7:
> note: Assuming 'CapHdrOffsets' is not equal to NULL
> # if (CapHdrOffsets == NULL) {
> # ^~~~~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:529:3:
> note: Taking false branch
> # if (CapHdrOffsets == NULL) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:546:3:
> note: Taking false branch
> # if (RETURN_ERROR (Status)) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:549:7:
> note: Assuming the condition is true
> # if ((PciStatusReg & EFI_PCI_STATUS_CAPABILITY) != 0) {
> # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:549:3:
> note: Taking true branch
> # if ((PciStatusReg & EFI_PCI_STATUS_CAPABILITY) != 0) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:557:5:
> note: Taking false branch
> # if (RETURN_ERROR (Status)) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:565:12:
> note: Assuming 'NormalCapHdrOffset' is > 0
> # while (NormalCapHdrOffset > 0) {
> # ^~~~~~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:565:5:
> note: Loop condition is true. Entering loop body
> # while (NormalCapHdrOffset > 0) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:570:7:
> note: Taking false branch
> # if (RETURN_ERROR (Status)) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:574:16:
> note: Calling 'InsertPciCap'
> # Status = InsertPciCap (OutCapList, CapHdrOffsets, PciCapNormal,
> # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:235:3:
> note: Null pointer value stored to 'InstanceZero'
> # InstanceZero = NULL;
> # ^~~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:243:7:
> note: Assuming 'PciCap' is not equal to NULL
> # if (PciCap == NULL) {
> # ^~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:243:3:
> note: Taking false branch
> # if (PciCap == NULL) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:259:3:
> note: Taking false branch
> # if (RETURN_ERROR (Status)) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:297:3:
> note: Taking false branch
> # if (RETURN_ERROR (Status)) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:311:7:
> note: Assuming the condition is true
> # if (PciCap->Key.Instance > 0) {
> # ^~~~~~~~~~~~~~~~~~~~~~~~
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:311:3:
> note: Taking true branch
> # if (PciCap->Key.Instance > 0) {
> # ^
> edk2-89910a39dcfd/OvmfPkg/Library/BasePciCapLib/BasePciCapLib.c:312:5:
> note: Dereference of null pointer
> # InstanceZero->NumInstancesUnion.NumInstances++;
> # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> # 310| //
> # 311| if (PciCap->Key.Instance > 0) {
> # 312|-> InstanceZero->NumInstancesUnion.NumInstances++;
> # 313| }
> # 314| return RETURN_SUCCESS;
The warning is invalid: the flagged dereferencing of "InstanceZero" is
gated by a condition that is only satisfied if we dereference
"InstanceZero" *first*.
(Perhaps the analyzer assumes that the OrderedCollectionInsert() call,
just before line 259, can change the value of "PciCap->Key.Instance" via
the last argument:
254 //
255 // Add PciCap to CapList.
256 //
257 Status = OrderedCollectionInsert (CapList->Capabilities, &PciCapEntry,
258 PciCap);
259 if (RETURN_ERROR (Status)) {
That assumption is incorrect.)
Add a comment and an ASSERT().
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org >
Cc: Jordan Justen <jordan.l.justen@intel.com >
Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=1710
Issue: scan-0994.txt
Signed-off-by: Laszlo Ersek <lersek@redhat.com >
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com >
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org >
2019-04-18 16:06:04 +02:00
Laszlo Ersek
392a31467f
OvmfPkg: introduce PciCapLib
...
Add a library class, and a BASE lib instance, to work more easily with PCI
capabilities in PCI config space. Functions are provided to parse
capabilities lists, and to locate, describe, read and write capabilities.
PCI config space access is abstracted away.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org >
Cc: Jordan Justen <jordan.l.justen@intel.com >
Suggested-by: Jordan Justen <jordan.l.justen@intel.com >
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com >
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org >
2018-05-24 21:12:06 +02:00
