readpwd: Make sure user supplies a passwdfile

If the user supplies enough command line arguments, but doesn't
provide a passwdfile, then we can end up trying to open whatever
garbage is on the stack.

Once we've finished parsing the command line arguments, make sure
that a filename was supplied.

Caught by coverity (#986009)

Reviewed-on: http://gerrit.openafs.org/9441
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit d81271640891fb8c364e8625e7a9f6ede21572f4)

Change-Id: I66d38c04c0f9519c401d3299e7d3ece57d001d96
Reviewed-on: http://gerrit.openafs.org/11052
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>

diff --git a/src/ptserver/readpwd.c b/src/ptserver/readpwd.c
index 46e3a9e15c946e54f440669d5227ae934468754a..32f7c4eb312e923d7254934b248156b0d233b08b 100644 (file)
--- a/src/ptserver/readpwd.c
+++ b/src/ptserver/readpwd.c
@@ -54,6 +54,8 @@ main(afs_int32 argc, char **argv)
     afs_int32 verbose = 0;
     char *cellname;
 
+    buf[0] = '\0';
+
     if (argc < 2) {
        fprintf(stderr, "Usage: readpwd [-v] [-c cellname] passwdfile.\n");
        exit(1);
@@ -70,6 +72,12 @@ main(afs_int32 argc, char **argv)
                strncpy(buf, argv[i], 150);
        }
     }
+
+    if (buf[0] == '\0') {
+       fprintf(stderr, "Usage: readpwd [-v] [-c cellname] passwdfile.\n");
+       exit(1);
+    }
+
     code = pr_Initialize(2, AFSDIR_CLIENT_ETC_DIRPATH, cellname);
     free(cellname);
     if (code) {