krb5: Fix null dereference in SPNEGO token processing

krb5 1.22.1 erroneously removed a check from get_negTokenResp() for
successful decoding of the mechListMIC field.  Restore the check to
prevent a null pointer dereference.

Commit message details obtained from upstream commit.
Obtained from:	Upstream commit 4ae75cded
MFC after:	3 days

This commit is contained in:

Cy Schubert

2026-06-02 10:57:17 -07:00

parent 37e9d3641b

commit efb5c07f91

1 changed files with 2 additions and 0 deletions

									
										crypto/krb5/src/lib/gssapi/spnego/spnego_mech.c
									
		+2
		
												View File
												
				@@ -3517,6 +3517,8 @@ get_negTokenResp(OM_uint32 *minor_status, struct k5input *in,

					if (k5_der_get_value(&seq, CONTEXT | 0x03, &field)) {

						*mechListMIC = get_octet_string(&field);

						if (*mechListMIC == GSS_C_NO_BUFFER)

							return GSS_S_DEFECTIVE_TOKEN;

				                /* Handle Windows 2000 duplicate response token */

				                if (*responseToken &&