s3: smbd: fix regression with non-wide symlinks to directories over SMB3.

The errno returned by open() is ambiguous when called with flags O_NOFOLLOW and
O_DIRECTORY on a symlink. With ELOOP, we know for certain that we've tried to
open a symlink. With ENOTDIR, we might have hit a symlink, and need to perform
further checks to be sure. Adjust non_widelink_open() accordingly. This fixes
a regression where symlinks to directories within the same share were no
longer followed for some call paths on systems returning ENOTDIR in the above
case.

Also remove the knownfail added in previous commit.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12860

Signed-off-by: Daniel Kobras <d.kobras@science-computing.de>
Reviewed-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
(cherry picked from commit acc16592b451905dabc093f1d261e93cd3b59520)

diff --git a/selftest/knownfail b/selftest/knownfail
index 84e2640fa1942e405e5280a45246a769da7d0db6..17667cd29d0418a1ebbe4f3aa2a29b69afb9dfd0 100644 (file)
--- a/selftest/knownfail
+++ b/selftest/knownfail
@@ -290,4 +290,3 @@
 ^samba4.drs.ridalloc_exop.python.*ridalloc_exop.DrsReplicaSyncTestCase.test_join_time_ridalloc
 ^samba4.drs.ridalloc_exop.python.*ridalloc_exop.DrsReplicaSyncTestCase.test_rid_set_dbcheck_after_seize
 ^samba4.drs.ridalloc_exop.python.*ridalloc_exop.DrsReplicaSyncTestCase.test_rid_set_dbcheck
-+^samba3.blackbox.smbclient_s3.*follow local symlinks.*

diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index 3368bae6ea2bbd187804fd0838129b6b13bcbd14..c96bc9ba98d02c9f6fea4043e69ebb08a44cd849 100644 (file)
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -579,7 +579,18 @@ static int non_widelink_open(struct connection_struct *conn,
 
        if (fd == -1) {
                saved_errno = link_errno_convert(errno);
-               if (saved_errno == ELOOP) {
+               /*
+                * Trying to open a symlink to a directory with O_NOFOLLOW and
+                * O_DIRECTORY can return either of ELOOP and ENOTDIR. So
+                * ENOTDIR really means: might be a symlink, but we're not sure.
+                * In this case, we just assume there's a symlink. If we were
+                * wrong, process_symlink_open() will return EINVAL. We check
+                * this below, and fall back to returning the initial
+                * saved_errno.
+                *
+                * BUG: https://bugzilla.samba.org/show_bug.cgi?id=12860
+                */
+               if (saved_errno == ELOOP || saved_errno == ENOTDIR) {
                        if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
                                /* Never follow symlinks on posix open. */
                                goto out;
@@ -589,7 +600,7 @@ static int non_widelink_open(struct connection_struct *conn,
                                goto out;
                        }
                        /*
-                        * We have a symlink. Follow in userspace
+                        * We may have a symlink. Follow in userspace
                         * to ensure it's under the share definition.
                         */
                        fd = process_symlink_open(conn,
@@ -600,6 +611,15 @@ static int non_widelink_open(struct connection_struct *conn,
                                        mode,
                                        link_depth);
                        if (fd == -1) {
+                               if (saved_errno == ENOTDIR &&
+                                               errno == EINVAL) {
+                                       /*
+                                        * O_DIRECTORY on neither a directory,
+                                        * nor a symlink. Just return
+                                        * saved_errno from initial open()
+                                        */
+                                       goto out;
+                               }
                                saved_errno =
                                        link_errno_convert(errno);
                        }