Fix for segfault in find(1)

[Gregor Best]

Hi people,

there's a tiny bug in find that causes a segmentation fault in find. The
following C program can be used to replicate a pathological directory
structure:

        #include <sys/stat.h>
        #include <string.h>
        #include <unistd.h>
        int main(void) {
                char s[256]; int i;
                memset(s, 'x', sizeof s);
                s[255] = 0;
                for (i = 0; i < 200; i++) {
                        mkdir(s, 0777);
                        chdir(s);
                }
                return 0;
        }

Calling

        find /path/to/structure -exec true '{}' ';'

on the directory structure created by the program causes a segmentation
fault in brace_subst(). The following patch fixes that by using the
return value of realloc() instead of stashing it away and continuing
with the old value.

-- 
        Gregor

Index: misc.c
===================================================================
RCS file: /mnt/media/cvs/src/usr.bin/find/misc.c,v
retrieving revision 1.12
diff -u -p -u -r1.12 misc.c
--- misc.c      18 May 2014 08:10:00 -0000      1.12
+++ misc.c      14 Jul 2015 15:41:20 -0000
@@ -66,6 +66,7 @@ brace_subst(char *orig, char **store, ch
                                if (!(newstore = realloc(*store, newlen)))
                                        err(1, NULL);
                                *store = newstore;
+                               p = newstore;
                                len = newlen;
                        }
                        memmove(p, path, plen);