Re: [Patch] MdeModulePkg BrotliDecompressLib: Add the checker to avoid array out of bound

["Gao, Liming" <liming.gao@intel.com>]

Yes. I will add those information. Thanks!

> -----Original Message-----
> From: Zeng, Star
> Sent: Wednesday, October 17, 2018 4:45 PM
> To: Gao, Liming <liming.gao@intel.com>; edk2-devel@lists.01.org
> Cc: Zeng, Star <star.zeng@intel.com>
> Subject: RE: [edk2] [Patch] MdeModulePkg BrotliDecompressLib: Add the checker to avoid array out of bound
> 
> Liming,
> 
> They are reported by some static analysis tool, right?
> I think you add some information about it in the commit log. You can do that when pushing the patch.
> 
> Thanks,
> Star
> -----Original Message-----
> From: Zeng, Star
> Sent: Wednesday, October 17, 2018 4:43 PM
> To: Gao, Liming <liming.gao@intel.com>; edk2-devel@lists.01.org
> Cc: Zeng, Star <star.zeng@intel.com>
> Subject: RE: [edk2] [Patch] MdeModulePkg BrotliDecompressLib: Add the checker to avoid array out of bound
> 
> Reviewed-by: Star Zeng <star.zeng@intel.com>
> 
> 
> Thanks,
> Star
> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Liming Gao
> Sent: Tuesday, October 16, 2018 3:27 PM
> To: edk2-devel@lists.01.org
> Subject: [edk2] [Patch] MdeModulePkg BrotliDecompressLib: Add the checker to avoid array out of bound
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Liming Gao <liming.gao@intel.com>
> ---
>  MdeModulePkg/Library/BrotliCustomDecompressLib/dec/decode.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/MdeModulePkg/Library/BrotliCustomDecompressLib/dec/decode.c
> b/MdeModulePkg/Library/BrotliCustomDecompressLib/dec/decode.c
> index fd42b3b..f3b3cb8 100644
> --- a/MdeModulePkg/Library/BrotliCustomDecompressLib/dec/decode.c
> +++ b/MdeModulePkg/Library/BrotliCustomDecompressLib/dec/decode.c
> @@ -858,6 +858,7 @@ static BROTLI_INLINE uint32_t ReadBlockLength(const HuffmanCode* table,
>    uint32_t code;
>    uint32_t nbits;
>    code = ReadSymbol(table, br);
> +  ASSERT (code < BROTLI_NUM_BLOCK_LEN_SYMBOLS);
>    nbits = kBlockLengthPrefixCode[code].nbits;  /* nbits == 2..24 */
>    return kBlockLengthPrefixCode[code].offset + BrotliReadBits(br, nbits);  } @@ -910,6 +911,7 @@ static BROTLI_NOINLINE void
> InverseMoveToFrontTransform(
>    uint32_t upper_bound = state->mtf_upper_bound;
>    uint32_t* mtf = &state->mtf[1];  /* Make mtf[-1] addressable. */
>    uint8_t* mtf_u8 = (uint8_t*)mtf;
> +  uint8_t* mtf_u8t = mtf_u8 - 1;
>    /* Load endian-aware constant. */
>    const uint8_t b0123[4] = {0, 1, 2, 3};
>    uint32_t pattern;
> @@ -928,13 +930,13 @@ static BROTLI_NOINLINE void InverseMoveToFrontTransform(
>    for (i = 0; i < v_len; ++i) {
>      int index = v[i];
>      uint8_t value = mtf_u8[index];
> -    upper_bound |= v[i];
> +    upper_bound |= (uint32_t) v[i];
>      v[i] = value;
> -    mtf_u8[-1] = value;
> -    do {
> +    mtf_u8t[0] = value;
> +    while (index >= 0) {
> +      mtf_u8t[index + 1] = mtf_u8t[index];
>        index--;
> -      mtf_u8[index + 1] = mtf_u8[index];
> -    } while (index >= 0);
> +    }
>    }
>    /* Remember amount of elements to be reinitialized. */
>    state->mtf_upper_bound = upper_bound >> 2; @@ -1566,6 +1568,7 @@ static BROTLI_INLINE BROTLI_BOOL
> ReadCommandInternal(
>    BrotliBitReaderState memento;
>    if (!safe) {
>      cmd_code = ReadSymbol(s->htree_command, br);
> +    ASSERT (cmd_code < BROTLI_NUM_COMMAND_SYMBOLS);
>    } else {
>      BrotliBitReaderSaveState(br, &memento);
>      if (!SafeReadSymbol(s->htree_command, br, &cmd_code)) {
> --
> 2.10.0.windows.1
> 
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