[edk2-devel] [PATCH v1 1/6] ShellPkg: acpiview: Allow passing buffer length to DumpGasStruct()
Krzysztof Koch
krzysztof.koch at arm.com
Fri Jul 19 10:40:45 UTC 2019
Hi Zhichao,
Sorry about private emails, I just mistakenly hit the wrong button. I forgot that the emails do not get sent to the mailing list unless I hit 'Reply all' (silly mistake).
I see your point. I will submit v2 of this patchset with:
> DumpGasStruct (DataPtr, 4, *DbgDevInfoLen);
Replaced with
> DumpGasStruct (DataPtr, 4, GAS_LENGTH);
Is that ok?
Kind regards,
Krzysztof
-----Original Message-----
From: Gao, Zhichao <zhichao.gao at intel.com>
Sent: Friday, July 19, 2019 9:09
To: Krzysztof Koch <Krzysztof.Koch at arm.com>
Subject: RE: [PATCH v1 1/6] ShellPkg: acpiview: Allow passing buffer length to DumpGasStruct()
HI Krzysztof,
Why do you send the email to me only? I think it is fine to send to the community. It would let more people who are interest with this component join the discuss. Maybe not . :(
Then for your comments:
Sorry, I missed the commit message before. But I don't think keeping an inappropriate code with a commit massage to explain that is OK. If you have a plan to fix that, it should combine into one patch.
Back to the code, I don't find out the possibility of overrun of buffer when use 'GAS_LENGTH'. And DataPtr + * DbgDevInfoLen definitely overflow.
DevInfoPtr DataPtr EndDevInfoPtr
---|---------------------------|------------------------------|----
|<-- DbgDevInfoLen -> |
Thanks,
Zhichao
> -----Original Message-----
> From: Krzysztof Koch [mailto:Krzysztof.Koch at arm.com]
> Sent: Friday, July 19, 2019 3:39 PM
> To: Gao, Zhichao <zhichao.gao at intel.com>
> Subject: RE: [PATCH v1 1/6] ShellPkg: acpiview: Allow passing buffer
> length to
> DumpGasStruct()
>
> Hi Zhichao,
>
> Please see my comments inline marked as [Krzysztof]
>
> Kind regards,
>
> Krzysztof
>
> -----Original Message-----
> From: Gao, Zhichao <zhichao.gao at intel.com>
> Sent: Friday, July 19, 2019 2:15
> To: Krzysztof Koch <Krzysztof.Koch at arm.com>; devel at edk2.groups.io
> Cc: Carsey, Jaben <jaben.carsey at intel.com>; Ni, Ray
> <ray.ni at intel.com>; Sami Mujawar <Sami.Mujawar at arm.com>; Matteo
> Carlini <Matteo.Carlini at arm.com>; nd <nd at arm.com>
> Subject: RE: [PATCH v1 1/6] ShellPkg: acpiview: Allow passing buffer
> length to
> DumpGasStruct()
>
>
>
> > -----Original Message-----
> > From: Krzysztof Koch [mailto:krzysztof.koch at arm.com]
> > Sent: Thursday, July 18, 2019 8:32 PM
> > To: devel at edk2.groups.io
> > Cc: Carsey, Jaben <jaben.carsey at intel.com>; Ni, Ray
> > <ray.ni at intel.com>; Gao, Zhichao <zhichao.gao at intel.com>;
> > Sami.Mujawar at arm.com; Matteo.Carlini at arm.com; nd at arm.com
> > Subject: [PATCH v1 1/6] ShellPkg: acpiview: Allow passing buffer
> > length to
> > DumpGasStruct()
> >
> > Modify the signature of the DumpGasStruct() function to include the
> > buffer length parameter and to return the number of bytes parsed by
> > the
> function.
> >
> > This way it becomes possible to prevent buffer overruns when dumping
> > Generic Address Structure's (GAS) fields in the acpiview table parsers.
> >
> > Update all existing DumpGasStruct() calls in acpiview to add the
> > length argument.
> >
> > Signed-off-by: Krzysztof Koch <krzysztof.koch at arm.com>
> > ---
> >
> > Notes:
> > v1:
> > - Modify DumpGasStruct() signature [Krzysztof]
> >
> > ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c | 26
> > +++++++++++---------
> > ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h | 8
> > ++++--
> >
> >
> ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c
> > | 2 +-
> > 3 files changed, 22 insertions(+), 14 deletions(-)
> >
> > diff --git
> > a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
> > b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
> > index
> >
> 8b3153516d2b7d9b920ab2de0344c17798ac572c..2d6ff80e299eebe7853061d3
> > db89332197c0dc0e 100644
> > --- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
> > +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
> > @@ -589,23 +589,27 @@ STATIC CONST ACPI_PARSER GasParser[] = {
> >
> > @param [in] Ptr Pointer to the start of the buffer.
> > @param [in] Indent Number of spaces to indent the output.
> > + @param [in] Length Length of the GAS structure buffer.
> > +
> > + @retval Number of bytes parsed.
> > **/
> > -VOID
> > +UINT32
> > EFIAPI
> > DumpGasStruct (
> > IN UINT8* Ptr,
> > - IN UINT32 Indent
> > + IN UINT32 Indent,
> > + IN UINT32 Length
> > )
> > {
> > Print (L"\n");
> > - ParseAcpi (
> > - TRUE,
> > - Indent,
> > - NULL,
> > - Ptr,
> > - GAS_LENGTH,
> > - PARSER_PARAMS (GasParser)
> > - );
> > + return ParseAcpi (
> > + TRUE,
> > + Indent,
> > + NULL,
> > + Ptr,
> > + Length,
> > + PARSER_PARAMS (GasParser)
> > + );
> > }
> >
> > /**
> > @@ -621,7 +625,7 @@ DumpGas (
> > IN UINT8* Ptr
> > )
> > {
> > - DumpGasStruct (Ptr, 2);
> > + DumpGasStruct (Ptr, 2, GAS_LENGTH);
> > }
> >
> > /**
> > diff --git
> > a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
> > b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
> > index
> >
> 7657892d9fd2e2e14c6578611ff0cf1b6f6cd750..20ca358bddfa5953bfb1d1beba
> > ebbf3079eaba01 100644
> > --- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
> > +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
> > @@ -405,12 +405,16 @@ ParseAcpi (
> >
> > @param [in] Ptr Pointer to the start of the buffer.
> > @param [in] Indent Number of spaces to indent the output.
> > + @param [in] Length Length of the GAS structure buffer.
> > +
> > + @retval Number of bytes parsed.
> > **/
> > -VOID
> > +UINT32
> > EFIAPI
> > DumpGasStruct (
> > IN UINT8* Ptr,
> > - IN UINT32 Indent
> > + IN UINT32 Indent,
> > + IN UINT32 Length
> > );
> >
> > /**
> > diff --git
> >
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parse
> > r.c
> >
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parse
> > r.c
> > index
> >
> 8de5ebf74775bab8e765849cba6ef4eb6f659a5a..2c47a3f848aa2dd512c53343e
> > cf1c3c285173dd6 100644
> > ---
> >
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parse
> > r.c
> > +++
> >
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Pars
> > +++ er.c
> > @@ -164,7 +164,7 @@ DumpDbgDeviceInfo (
> > AddrSize = (UINT32*)(Ptr + (*AddrSizeOffset));
> > while (Index < (*GasCount)) {
> > PrintFieldName (4, L"BaseAddressRegister");
> > - DumpGasStruct (DataPtr, 4);
> > + DumpGasStruct (DataPtr, 4, *DbgDevInfoLen);
>
> This input length should be GAS_LENGTH. *DbgDevInfoLen is the length
> of the whole structure and the DataPtr is increased during the loop.
> Inputing such a length would give the ParseAcpi function a chance to
> overrun the DataPtr.
>
> Thanks,
> Zhichao
>
> [Krzysztof] You're right. This patch does not eliminate the
> possibility for a buffer overrun when parsing the GAS structure. This
> patch series does not implement that yet, it's merely a refactoring
> change in preparation for the patches which actually deal with the
> problem. The patches which prevent buffer overruns in acpiview parsers
> are pending on the patches which are currently in review.
>
> In the commit message I state that the change of the DumpGasStruct()
> function signature makes it "possible to prevent buffer overruns when
> dumping Generic Address Structure's (GAS) fields in the acpiview table
> parsers." The validation is coming soon.
>
> > PrintFieldName (4, L"Address Size");
> > Print (L"0x%x\n", AddrSize[Index]);
> > DataPtr += GAS_LENGTH;
> > --
> > 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
> >
>
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