As I have discussed previously (more recently here, here and here), a majority of jurisdictions hold that a convicted criminal defendant does not have a right to sue his or her trial attorney for legal malpractice unless the plaintiff can show he or she was innocent of the crime.
In a slightly different type of case, the Oregon Supreme Court recently ruled, however, that a convicted criminal defense client need not obtain exoneration of the underlying offense before suing his or her lawyers. The case is called Drollinger v. Mallon, and it is available here. The case is slightly different because the plaintiff's allegation was that the lawyer was negligent in handling a post-conviction appeal. The court found that exoneration is not required in the post-conviction malpractice setting because the policies underlying the exoneration requirement in an action involving alleged trial malpractice do not apply to an action in which a client's failure to obtain post-conviction relief is the heart of the case.