| Message ID | 20181130112829.12173-3-ard.biesheuvel@linaro.org |
|---|---|
| State | Accepted |
| Commit | aa1097921d7581a8a9c527d5beb3d9d97c731f7e |
| Headers | show |
| Series | ArmVirtQemu: unmap page #0 to catch NULL pointer dereferences | expand |
On Fri, Nov 30, 2018 at 12:28:27PM +0100, Ard Biesheuvel wrote: > The ARM ArmMmuLib code currently does not take into account that > setting permissions on a region should take into account that a > region may not be mapped yet to begin with. > > So when updating a section descriptor whose old value is zero, > pass in the address explicitly. > > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org> > --- > ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c > index ec51e072ab43..889b22867dc7 100644 > --- a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c > +++ b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c > @@ -695,8 +695,12 @@ UpdateSectionEntries ( > } else { > // still a section entry > > - // mask off appropriate fields > - Descriptor = CurrentDescriptor & ~EntryMask; > + if (CurrentDescriptor != 0) { > + // mask off appropriate fields > + Descriptor = CurrentDescriptor & ~EntryMask; > + } else { > + Descriptor = ((UINTN)FirstLevelIdx + i) << TT_DESCRIPTOR_SECTION_BASE_SHIFT; > + } > > // mask in new attributes and/or permissions > Descriptor |= EntryValue; > -- > 2.19.1 > _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
diff --git a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c index ec51e072ab43..889b22867dc7 100644 --- a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c +++ b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c @@ -695,8 +695,12 @@ UpdateSectionEntries ( } else { // still a section entry - // mask off appropriate fields - Descriptor = CurrentDescriptor & ~EntryMask; + if (CurrentDescriptor != 0) { + // mask off appropriate fields + Descriptor = CurrentDescriptor & ~EntryMask; + } else { + Descriptor = ((UINTN)FirstLevelIdx + i) << TT_DESCRIPTOR_SECTION_BASE_SHIFT; + } // mask in new attributes and/or permissions Descriptor |= EntryValue;
The ARM ArmMmuLib code currently does not take into account that setting permissions on a region should take into account that a region may not be mapped yet to begin with. So when updating a section descriptor whose old value is zero, pass in the address explicitly. Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) -- 2.19.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel