bin/175491: [libelf] elf_getdata may return NULL without setting error-message

[Mark Johnston]

The following reply was made to PR bin/175491; it has been noted by GNATS.

From: Mark Johnston <markj at freebsd.org>
To: bug-followup at FreeBSD.org, mi at aldan.algebra.com
Cc:  
Subject: Re: bin/175491: [libelf] elf_getdata may return NULL without setting
 error-message
Date: Sun, 17 Feb 2013 00:31:03 -0500

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 Looks like this was fixed in upstream libelf with r1765 and r1766. The
 same bug exists in elf_rawdata(), and this han't been fixed upstream
 either. I'll try to get this fixed both upstream and in FreeBSD's
 libelf; in the meantime, the attached patch should fix the problem.
 
 -Mark
 
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 diff --git a/lib/libelf/elf_data.c b/lib/libelf/elf_data.c
 index c34c4ad..d3bd390 100644
 --- a/lib/libelf/elf_data.c
 +++ b/lib/libelf/elf_data.c
 @@ -78,8 +78,10 @@ elf_getdata(Elf_Scn *s, Elf_Data *d)
  		sh_align  = s->s_shdr.s_shdr64.sh_addralign;
  	}
  
 -	if (sh_type == SHT_NULL)
 +	if (sh_type == SHT_NULL) {
 +		LIBELF_SET_ERROR(SECTION, 0);
  		return (NULL);
 +	}
  
  	if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
  	    elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
 @@ -219,8 +221,10 @@ elf_rawdata(Elf_Scn *s, Elf_Data *d)
  		sh_align  = s->s_shdr.s_shdr64.sh_addralign;
  	}
  
 -	if (sh_type == SHT_NULL)
 +	if (sh_type == SHT_NULL) {
 +		LIBELF_SET_ERROR(SECTION, 0);
  		return (NULL);
 +	}
  
  	if ((d = _libelf_allocate_data(s)) == NULL)
  		return (NULL);
 
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