Hi Zhiguang,
Thank you for reviewing my commit.
I thought, the variable was used only once in the if {} statement, so had
it declared only there.
I will declare it in the beginning of the function if it is a standard.
Will submit patch v2.
Thank you,
Vladimir
> -----Original Message-----
> From: Liu, Zhiguang <[email protected]>
> Sent: Saturday, June 27, 2020 11:31 PM
> To: [email protected]; [email protected]
> Cc: Kinney, Michael D <[email protected]>; Gao, Liming
> <[email protected]>
> Subject: RE: [edk2-devel] [PATCH v1 1/1] MdePkg : UefiFileHandleLib: fix
> buffer overrun in FileHandleReadLine()
>
> Hi Vladimir
> Thanks for catching this bug. And I agree with you about your code
change.
> One little problem is that we always define the variable in the
beginning of
> the function.
> Please fix the little issue and I will give my RB.
>
> Thanks
> Zhiguang
>
> > -----Original Message-----
> > From: [email protected] <[email protected]> On Behalf Of
> > Vladimir Olovyannikov via groups.io
> > Sent: Friday, June 5, 2020 8:18 AM
> > To: [email protected]
> > Cc: Vladimir Olovyannikov <[email protected]>;
> > Kinney, Michael D <[email protected]>; Gao, Liming
> > <[email protected]>
> > Subject: [edk2-devel] [PATCH v1 1/1] MdePkg : UefiFileHandleLib: fix
> > buffer overrun in FileHandleReadLine()
> >
> > If the size of the supplied buffer in FileHandleReadLine(), module
> > UefiFileHandleLib.c, was not 0, but was not enough to fit in the line,
> > the size is increased, and then the Buffer of the new size is zeroed.
> > This size is always larger than the supplied buffer size, causing
> > supplied buffer overrun. Fix the issue by using the supplied buffer
> > size in ZeroMem().
> >
> > Signed-off-by: Vladimir Olovyannikov
> > <[email protected]>
> > Cc: Michael D Kinney <[email protected]>
> > Cc: Liming Gao <[email protected]>
> > ---
> > MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
> > b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
> > index 28e28e5f67d5..4bc9fabb6c74 100644
> > --- a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
> > +++ b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
> > @@ -1039,10 +1039,13 @@ FileHandleReadLine(
> > // if we ran out of space tell when...
> >
> > //
> >
> > if ((CountSoFar+1-CrCount)*sizeof(CHAR16) > *Size){
> >
> > + UINTN OldSize;
> >
> > +
> >
> > + OldSize = *Size;
> >
> > *Size = (CountSoFar+1-CrCount)*sizeof(CHAR16);
> >
> > if (!Truncate) {
> >
> > - if (Buffer != NULL && *Size != 0) {
> >
> > - ZeroMem(Buffer, *Size);
> >
> > + if (Buffer != NULL && OldSize != 0) {
> >
> > + ZeroMem(Buffer, OldSize);
> >
> > }
> >
> > FileHandleSetPosition(Handle, OriginalFilePosition);
> >
> > return (EFI_BUFFER_TOO_SMALL);
> >
> > --
> > 2.26.2.266.ge870325ee8
> >
> >
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