Fix a bug whereby 'mformat' could end up passing uninitialized bytes to write(2). This could be reproduced with: mformat -C -f 1440 -L 16 -N 77777777 -i /tmp/x :: where the output of /tmp/x would be non-deterministic. Patch by Ludovic Courtès <ludo@gnu.org>. --- mtools-4.0.23/mformat.c 2019-04-21 00:12:01.496116195 +0200 +++ mtools-4.0.23/mformat.c 2019-04-21 00:12:36.675967157 +0200 @@ -927,6 +927,7 @@ void mformat(int argc, char **argv, int char *endptr; + memset(&boot.bytes, '\0', sizeof boot); hs = hs_set = 0; argtracks = 0; argheads = 0;