Laszlo: I agree with you. MAX_UINT32 is more comfortable.
Thanks Liming >-----Original Message----- >From: Laszlo Ersek [mailto:ler...@redhat.com] >Sent: Monday, December 03, 2018 9:06 PM >To: Ard Biesheuvel <ard.biesheu...@linaro.org>; edk2-devel@lists.01.org >Cc: Zhu, Yonghong <yonghong....@intel.com>; Gao, Liming ><liming....@intel.com>; Feng, Bob C <bob.c.f...@intel.com>; Carsey, Jaben ><jaben.car...@intel.com> >Subject: Re: [PATCH v2 4/6] BaseTools/DevicePath: use MAX_UINT16 as >default device path max size > >On 11/30/18 23:45, Ard Biesheuvel wrote: >> Replace the default size limit of IsDevicePathValid() with a value >> that does not depend on the native word size of the build host. >> >> 64 KB seems sufficient as the upper bound of a device path handled >> by UEFI. >> >> Contributed-under: TianoCore Contribution Agreement 1.1 >> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> >> Reviewed-by: Jaben Carsey <jaben.car...@intel.com> >> --- >> BaseTools/Source/C/DevicePath/DevicePathUtilities.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/BaseTools/Source/C/DevicePath/DevicePathUtilities.c >b/BaseTools/Source/C/DevicePath/DevicePathUtilities.c >> index d4ec2742b7c8..ba7f83e53070 100644 >> --- a/BaseTools/Source/C/DevicePath/DevicePathUtilities.c >> +++ b/BaseTools/Source/C/DevicePath/DevicePathUtilities.c >> @@ -62,7 +62,7 @@ IsDevicePathValid ( >> ASSERT (DevicePath != NULL); >> >> if (MaxSize == 0) { >> - MaxSize = MAX_UINTN; >> + MaxSize = MAX_UINT16; >> } >> >> // >> @@ -78,7 +78,7 @@ IsDevicePathValid ( >> return FALSE; >> } >> >> - if (NodeLength > MAX_UINTN - Size) { >> + if (NodeLength > MAX_UINT16 - Size) { >> return FALSE; >> } >> Size += NodeLength; >> > >I'm somewhat undecided about this patch. > >(1) IsDevicePathValid() also exists in: > >- MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c >- MdePkg/Library/UefiDevicePathLibDevicePathProtocol/UefiDevicePathLib.c > >Both have: > > if (MaxSize == 0) { > MaxSize = MAX_UINTN; > } > >Relative to those, this change departs quite strongly. > > >(2) In addition, a single device path node may extend up to 64KB. That >would be pathologic, yes, but the option is there. > > >... Of course, we are discussing theoretical limits. Still I'd feel more >comfortable with MAX_UINT32. Lifting the limit from 64K to 4G wouldn't >cost us anything (in development effort), it would be a no-op on 32-bit >build hosts, it would be a theoretical-only change on 64-bit build >hosts, and it would leave us with a larger "safety margin". > >I won't insist, but I thought I should raise this. (Sorry if this has >been discussed under v1 already.) If you agree, no need to repost (from >my side anyway) just for this. > >With or without the update: > >Reviewed-by: Laszlo Ersek <ler...@redhat.com> > >Thanks >Laszlo _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
