Re: [PATCH v3] mips: dl-machine-reject-phdr: Get rid of alloca.

["Ying Huang" <ying.huang@oss.cipunited.com>]

[-- Attachment #1: Type: text/plain, Size: 3464 bytes --]

Hi Joe,

在 2023/8/30 20:29, Joe Simmons-Talbott 写道:
> On Wed, Aug 30, 2023 at 04:18:58PM +0800, Ying Huang wrote:
>> Hi,
>>
>> I have tested this patch on my lab, the resutls of make and make check all were good.
>>
>> And make check did not introduce new XFAILS.
>>
>> The environment is:
>>
>> gcc 12.2.0, binutils 2.40, mips64el-linux-gnuabi64
> Thank you for testing.  May I add a Tested-by: line?
>
> Thanks,
> Joe

Yes,  my pleasure.

And I also did test on gcc 12.2.0, binutils 2.40, mipsel-linux-gnu.  It was good, too.

>>
>> Thanks,
>>
>> Ying
>>
>>
>> 在 2023/8/30 03:30, Joe Simmons-Talbott via Libc-alpha 写道:
>>> Ping.
>>>
>>> On Mon, Jun 26, 2023 at 09:16:21AM -0400, Joe Simmons-Talbott wrote:
>>>> Read directly into the mips_abiflags struct rather than reading the
>>>> entire segment and using alloca when the passed buffer is not big enough.
>>>>
>>>> Checked with build-many-glibcs.py on mips-linux-gnu
>>>> ---
>>>> Changes to v2:
>>>>   * Rather than use a scratch buffer use the mips_abiflags struct itself
>>>>     for reading since we're now just reading that much data and not the
>>>>     whole segment.
>>>>
>>>>  sysdeps/mips/dl-machine-reject-phdr.h | 26 ++++++++++----------------
>>>>  1 file changed, 10 insertions(+), 16 deletions(-)
>>>>
>>>> diff --git a/sysdeps/mips/dl-machine-reject-phdr.h b/sysdeps/mips/dl-machine-reject-phdr.h
>>>> index 104b590661..b784697fc1 100644
>>>> --- a/sysdeps/mips/dl-machine-reject-phdr.h
>>>> +++ b/sysdeps/mips/dl-machine-reject-phdr.h
>>>> @@ -161,7 +161,7 @@ elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, unsigned int phnum,
>>>>    Lmid_t nsid;
>>>>    int in_abi = -1;
>>>>    struct abi_req in_req;
>>>> -  Elf_MIPS_ABIFlags_v0 *mips_abiflags = NULL;
>>>> +  Elf_MIPS_ABIFlags_v0 mips_abiflags;
>>>>    bool perfect_match = false;
>>>>  #if _MIPS_SIM == _ABIO32
>>>>    unsigned int cur_mode = -1;
>>>> @@ -176,25 +176,19 @@ elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, unsigned int phnum,
>>>>    /* Read the attributes section.  */
>>>>    if (ph != NULL)
>>>>      {
>>>> -      ElfW(Addr) size = ph->p_filesz;
>>>> +      ElfW(Addr) size = sizeof (Elf_MIPS_ABIFlags_v0);
>>>>  
>>>> -      if (ph->p_offset + size <= len)
>>>> -	mips_abiflags = (Elf_MIPS_ABIFlags_v0 *) (buf + ph->p_offset);
>>>> -      else
>>>> -	{
>>>> -	  mips_abiflags = alloca (size);
>>>> -	  __lseek (fd, ph->p_offset, SEEK_SET);
>>>> -	  if (__libc_read (fd, (void *) mips_abiflags, size) != size)
>>>> -	    REJECT ("   unable to read PT_MIPS_ABIFLAGS\n");
>>>> -	}
>>>> -
>>>> -      if (size < sizeof (Elf_MIPS_ABIFlags_v0))
>>>> +      if (ph->p_filesz < size)
>>>>  	REJECT ("   contains malformed PT_MIPS_ABIFLAGS\n");
>>>>  
>>>> -      if (__glibc_unlikely (mips_abiflags->flags2 != 0))
>>>> -	REJECT ("   unknown MIPS.abiflags flags2: %u\n", mips_abiflags->flags2);
>>>> +      __lseek (fd, ph->p_offset, SEEK_SET);
>>>> +      if (__libc_read (fd, (void *) &mips_abiflags, size) != size)
>>>> +	REJECT ("   unable to read PT_MIPS_ABIFLAGS\n");
>>>> +
>>>> +      if (__glibc_unlikely (mips_abiflags.flags2 != 0))
>>>> +	REJECT ("   unknown MIPS.abiflags flags2: %u\n", mips_abiflags.flags2);
>>>>  
>>>> -      in_abi = mips_abiflags->fp_abi;
>>>> +      in_abi = mips_abiflags.fp_abi;
>>>>      }
>>>>  
>>>>    /* ANY is compatible with anything.  */
>>>> -- 
>>>> 2.39.2
>>>>