pull up r22175 from trunk

pull up r22175 from trunk

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 r22175 | tlyu | 2009-04-07 17:22:20 -0400 (Tue, 07 Apr 2009) | 14 lines
 Changed paths:
    M /trunk/src/lib/krb5/asn.1/asn1buf.c

 ticket: 6444
 subject: CVE-2009-0847 asn1buf_imbed incorrect length validation
 tags: pullup
 target_version: 1.7

 asn1buf_imbed() can perform pointer arithmetic that causes the "bound"
 pointer of the subbuffer to be less than the "next" pointer.  This can
 lead to malloc() failure or crash.

 In asn1buf_imbed(), check the length before doing arithmetic to set
 subbuf->bound.  In asn1buf_remove_octetstring() and
 asn1buf_remove_charstring(), check for invalid buffer pointers before
 executing an unsigned length check against a (casted to size_t)
 negative number.

ticket: 6444
version_fixed: 1.7

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-7@22249 dc483132-0cff-0310-8789-dd5450dbe970