Fix null pointer dereference in opj_j2k_add_mct() (#895)

Fixes openjeg-crashes-2017-07-27/issue879-poc1.j2k of #895

diff --git a/src/lib/openjp2/j2k.c b/src/lib/openjp2/j2k.c
index 89f2b45f08cbf16ae7ba84119eb6998259423096..b192f04fa1e9ac63442467aa005e51e1d3d7d076 100644 (file)
--- a/src/lib/openjp2/j2k.c
+++ b/src/lib/openjp2/j2k.c
@@ -5584,6 +5584,7 @@ static OPJ_BOOL opj_j2k_read_mct(opj_j2k_t *p_j2k,
     if (l_mct_data->m_data) {
         opj_free(l_mct_data->m_data);
         l_mct_data->m_data = 00;
+        l_mct_data->m_data_size = 0;
     }
 
     l_mct_data->m_index = l_indix;