From 65831b7ec829b0ae0ac9d691a2f8fbc2b26af677 Mon Sep 17 00:00:00 2001
From: tbeu <tbeu@users.noreply.github.com>
Date: Mon, 11 Nov 2019 22:03:54 +0100
Subject: [PATCH] Fix illegal memory access

As reported by https://github.com/tbeu/matio/issues/129

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Retrieved from:
https://github.com/tbeu/matio/commit/65831b7ec829b0ae0ac9d691a2f8fbc2b26af677]
---
 src/mat5.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/mat5.c b/src/mat5.c
index b76a331..5e3464e 100644
--- a/src/mat5.c
+++ b/src/mat5.c
@@ -989,10 +989,26 @@ ReadNextCell( mat_t *mat, matvar_t *matvar )
                 /* Rank and Dimension */
                 if ( uncomp_buf[0] == MAT_T_INT32 ) {
                     int j;
+                    size_t size;
                     cells[i]->rank = uncomp_buf[1];
                     nbytes -= cells[i]->rank;
                     cells[i]->rank /= 4;
-                    cells[i]->dims = (size_t*)malloc(cells[i]->rank*sizeof(*cells[i]->dims));
+                    if ( 0 == do_clean && cells[i]->rank > 13 ) {
+                        int rank = cells[i]->rank;
+                        cells[i]->rank = 0;
+                        Mat_Critical("%d is not a valid rank", rank);
+                        continue;
+                    }
+                    err = SafeMul(&size, cells[i]->rank, sizeof(*cells[i]->dims));
+                    if ( err ) {
+                        if ( do_clean )
+                            free(dims);
+                        Mat_VarFree(cells[i]);
+                        cells[i] = NULL;
+                        Mat_Critical("Integer multiplication overflow");
+                        continue;
+                    }
+                    cells[i]->dims = (size_t*)malloc(size);
                     if ( mat->byteswap ) {
                         for ( j = 0; j < cells[i]->rank; j++ )
                             cells[i]->dims[j] = Mat_uint32Swap(dims + j);