Re: [PATCH v2 1/1] MdePkg/BaseLib: Fix out-of-bounds reads in SafeString

["Yao, Jiewen" <jiewen.yao@intel.com>]

That is good catch.

Reviewed-by: Jiewen Yao <Jiewen.yao@Intel.com>


> -----Original Message-----
> From: Kinney, Michael D <michael.d.kinney@intel.com>
> Sent: Wednesday, October 26, 2022 12:23 AM
> To: Pedro Falcato <pedro.falcato@gmail.com>; devel@edk2.groups.io
> Cc: Vitaly Cheptsov <vit9696@protonmail.com>; Marvin Häuser
> <mhaeuser@posteo.de>; Gao, Liming <gaoliming@byosoft.com.cn>; Liu,
> Zhiguang <zhiguang.liu@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>
> Subject: RE: [PATCH v2 1/1] MdePkg/BaseLib: Fix out-of-bounds reads in
> SafeString
> 
> Adding Jiewen Yao.
> 
> Mike
> 
> > -----Original Message-----
> > From: Pedro Falcato <pedro.falcato@gmail.com>
> > Sent: Monday, October 24, 2022 3:43 PM
> > To: devel@edk2.groups.io
> > Cc: Pedro Falcato <pedro.falcato@gmail.com>; Vitaly Cheptsov
> <vit9696@protonmail.com>; Marvin Häuser <mhaeuser@posteo.de>;
> > Kinney, Michael D <michael.d.kinney@intel.com>; Gao, Liming
> <gaoliming@byosoft.com.cn>; Liu, Zhiguang <zhiguang.liu@intel.com>
> > Subject: [PATCH v2 1/1] MdePkg/BaseLib: Fix out-of-bounds reads in
> SafeString
> >
> > OpenCore folks established an ASAN-equipped project to fuzz Ext4Dxe,
> > which was able to catch these (mostly harmless) issues.
> >
> > Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
> > Cc: Vitaly Cheptsov <vit9696@protonmail.com>
> > Cc: Marvin Häuser <mhaeuser@posteo.de>
> > Cc: Michael D Kinney <michael.d.kinney@intel.com>
> > Cc: Liming Gao <gaoliming@byosoft.com.cn>
> > Cc: Zhiguang Liu <zhiguang.liu@intel.com>
> > ---
> >  MdePkg/Library/BaseLib/SafeString.c | 24 ++++++++++++++++++++----
> >  1 file changed, 20 insertions(+), 4 deletions(-)
> >
> > diff --git a/MdePkg/Library/BaseLib/SafeString.c
> b/MdePkg/Library/BaseLib/SafeString.c
> > index f338a32a3a41..77a2585ad56d 100644
> > --- a/MdePkg/Library/BaseLib/SafeString.c
> > +++ b/MdePkg/Library/BaseLib/SafeString.c
> > @@ -863,6 +863,9 @@ StrHexToUintnS (
> >    OUT       UINTN   *Data
> >    )
> >  {
> > +  BOOLEAN  FoundLeadingZero;
> > +
> > +  FoundLeadingZero = FALSE;
> >    ASSERT (((UINTN)String & BIT0) == 0);
> >
> >    //
> > @@ -893,11 +896,12 @@ StrHexToUintnS (
> >    // Ignore leading Zeros after the spaces
> >    //
> >    while (*String == L'0') {
> > +    FoundLeadingZero = TRUE;
> >      String++;
> >    }
> >
> >    if (CharToUpper (*String) == L'X') {
> > -    if (*(String - 1) != L'0') {
> > +    if (!FoundLeadingZero) {
> >        *Data = 0;
> >        return RETURN_SUCCESS;
> >      }
> > @@ -992,6 +996,9 @@ StrHexToUint64S (
> >    OUT       UINT64  *Data
> >    )
> >  {
> > +  BOOLEAN  FoundLeadingZero;
> > +
> > +  FoundLeadingZero = FALSE;
> >    ASSERT (((UINTN)String & BIT0) == 0);
> >
> >    //
> > @@ -1022,11 +1029,12 @@ StrHexToUint64S (
> >    // Ignore leading Zeros after the spaces
> >    //
> >    while (*String == L'0') {
> > +    FoundLeadingZero = TRUE;
> >      String++;
> >    }
> >
> >    if (CharToUpper (*String) == L'X') {
> > -    if (*(String - 1) != L'0') {
> > +    if (!FoundLeadingZero) {
> >        *Data = 0;
> >        return RETURN_SUCCESS;
> >      }
> > @@ -2393,6 +2401,9 @@ AsciiStrHexToUintnS (
> >    OUT       UINTN  *Data
> >    )
> >  {
> > +  BOOLEAN  FoundLeadingZero;
> > +
> > +  FoundLeadingZero = FALSE;
> >    //
> >    // 1. Neither String nor Data shall be a null pointer.
> >    //
> > @@ -2421,11 +2432,12 @@ AsciiStrHexToUintnS (
> >    // Ignore leading Zeros after the spaces
> >    //
> >    while (*String == '0') {
> > +    FoundLeadingZero = TRUE;
> >      String++;
> >    }
> >
> >    if (AsciiCharToUpper (*String) == 'X') {
> > -    if (*(String - 1) != '0') {
> > +    if (!FoundLeadingZero) {
> >        *Data = 0;
> >        return RETURN_SUCCESS;
> >      }
> > @@ -2517,6 +2529,9 @@ AsciiStrHexToUint64S (
> >    OUT       UINT64  *Data
> >    )
> >  {
> > +  BOOLEAN  FoundLeadingZero;
> > +
> > +  FoundLeadingZero = FALSE;
> >    //
> >    // 1. Neither String nor Data shall be a null pointer.
> >    //
> > @@ -2545,11 +2560,12 @@ AsciiStrHexToUint64S (
> >    // Ignore leading Zeros after the spaces
> >    //
> >    while (*String == '0') {
> > +    FoundLeadingZero = TRUE;
> >      String++;
> >    }
> >
> >    if (AsciiCharToUpper (*String) == 'X') {
> > -    if (*(String - 1) != '0') {
> > +    if (!FoundLeadingZero) {
> >        *Data = 0;
> >        return RETURN_SUCCESS;
> >      }
> > --
> > 2.38.1