[edk2-devel] [PATCH] MdeModulePkg/TerminalDxe [BUG]: Terminal fifo buffer overflow.

[Gao, Zhichao]

Add Hao and Jian, who have the permission to merge the patch. CI result: https://github.com/tianocore/edk2/pull/1358

Thanks,
Zhichao

> -----Original Message-----
> From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Gao, Zhichao
> Sent: Thursday, January 14, 2021 2:35 PM
> To: gechao at greatwall.com.cn
> Cc: devel at edk2.groups.io; Ni, Ray <ray.ni at intel.com>
> Subject: Re: [edk2-devel] [PATCH] MdeModulePkg/TerminalDxe [BUG]: Terminal
> fifo buffer overflow.
> 
> There is no need to add [BUG] in the title. I would remove it when I create the PR.
> If you want to have a record for this bug, you can edit a Bugzilla and add the link
> in the commit message.
> Beside of that, Reviewed-by: Zhichao Gao <zhichao.gao at intel.com>
> 
> Thanks,
> Zhichao
> 
> > -----Original Message-----
> > From: gechao at greatwall.com.cn <gechao at greatwall.com.cn>
> > Sent: Thursday, January 14, 2021 11:23 AM
> > To: Gao, Zhichao <zhichao.gao at intel.com>
> > Cc: devel at edk2.groups.io; Ni, Ray <ray.ni at intel.com>; gechao
> > <gechao at greatwall.com.cn>
> > Subject: [PATCH] MdeModulePkg/TerminalDxe [BUG]: Terminal fifo buffer
> > overflow.
> >
> > From: gechao <gechao at greatwall.com.cn>
> >
> > Fix the bug of terminal fifo buffer overflow with UINT8 type.
> >
> > typedef struct {
> >   UINT8 Head;
> >   UINT8 Tail;
> >   UINT8 Data[RAW_FIFO_MAX_NUMBER + 1]; } RAW_DATA_FIFO;
> > RAW_FIFO_MAX_NUMBER is 256.
> > the data buffer size is 257 (Index from 0 to 256), but the max value
> > of the index, Head or Tail (UINT8), is 255. That means the last data
> > of the data buffer would be always empty if we use Head/Tail to
> > output/input the data correctly.  And because of the incorrect buffer
> > size the FIFO full check "((Tail + 1) % (RAW_FIFO_MAX_NUMBER + 1)) == Head"
> would never meet.
> >
> > Signed-off-by: gechao <gechao at greatwall.com.cn>
> > ---
> >  MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
> > b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
> > index 378ace13ce..360e58e847 100644
> > --- a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
> > +++ b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
> > @@ -37,7 +37,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > #include <Library/BaseLib.h>  -#define RAW_FIFO_MAX_NUMBER 256+#define
> > RAW_FIFO_MAX_NUMBER 255 #define FIFO_MAX_NUMBER     128  typedef
> > struct {--
> > 2.25.1
> 
> 
> 
> 
> 



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