Re: [PATCH] chown: prevent multiple --from options

[Francois]

On Sun, 29 Sep 2019 at 14:36, Pádraig Brady <address@hidden> wrote:

>
> I'm inclined to agree with this patch,

Unfortunately I messed it up as the second from still erases the
content of the first... Another solution that would make the code
simpler would be to just die at the beginning of the second from
even if it sets a different id than the first one. Anyway, here is a
more correct version than the initial patch.

Thanks for your time!


* src/chown.c: prevent multiple --from options

* tests/chown/basic.sh: prevent multiple --from options
---
 src/chown.c          | 16 ++++++++++++++--
 tests/chown/basic.sh |  9 +++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/chown.c b/src/chown.c
index c1db307ab..8fe581192 100644
--- a/src/chown.c
+++ b/src/chown.c
@@ -227,11 +227,23 @@ main (int argc, char **argv)

         case FROM_OPTION:
           {
-            const char *e = parse_user_spec (optarg,
-                                             &required_uid, &required_gid,
+            const char *e;
+            uid_t parsed_required_uid = -1;
+            gid_t parsed_required_gid = -1;
+            e = parse_user_spec (optarg,
+                                             &parsed_required_uid,
+                                             &parsed_required_gid,
                                              NULL, NULL);
             if (e)
               die (EXIT_FAILURE, 0, "%s: %s", e, quote (optarg));
+            if ((parsed_required_uid != -1 && required_uid != -1) ||
+                (parsed_required_gid != -1 && required_gid != -1))
+              die (EXIT_FAILURE, 0, "%s",
+                   _("from option provided multiple times"));
+            if (parsed_required_uid != -1)
+              required_uid = parsed_required_uid;
+            if (parsed_required_gid != -1)
+              required_gid = parsed_required_gid;
             break;
           }

diff --git a/tests/chown/basic.sh b/tests/chown/basic.sh
index faeeb82aa..2ccfd959d 100755
--- a/tests/chown/basic.sh
+++ b/tests/chown/basic.sh
@@ -56,4 +56,13 @@ chown --no-dereference --from=0:1 2:010 slink || fail=1
 # owner/group on the symlink should be changed
 set _ $(ls -n slink); shift; test "$3:$4" = 2:10 || fail=1

+# Ensure two from are reported properly as error
+returns_ 1 chown --from=0:0 --from=1:1 0 f > out 2>&1|| fail=1
+printf "chown: from option provided multiple times\n" > exp
+compare exp out || fail=1
+
+# Unless they set different attributes
+chown --from=0 --from=:0 0 f  || fail=1
+
+
 Exit $fail
--
2.16.4