[PATCH] Fix regression with non-wide symlinks to directory over SMB3.
Jeremy Allison
jra at samba.org
Fri Jun 23 19:10:58 UTC 2017
Great catch (and fix) from Daniel Kobras <d.kobras at science-computing.de>
for bug: https://bugzilla.samba.org/show_bug.cgi?id=12860
I'll let him explain:
-----------------------------------------------------------
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.
-----------------------------------------------------------
Easy reproducer:
In the root of the share just do:
mkdir dir1
ln -s sym_to_dir dir1
Then:
smbclient //localhost/share -mSMB3
smb: \> cd sym_to_dir
smb: \sym_to_dir\> ls
NT_STATUS_NOT_A_DIRECTORY listing \sym_to_dir\*
I added a regression test to our test suite for this one.
Please review and push if happy !
Cheers,
Jeremy.
-------------- next part --------------
>From dd242011fb74577aa772cbc91f1843d047c5b925 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Fri, 23 Jun 2017 11:12:22 -0700
Subject: [PATCH 1/2] s3: smbd: Add regression test for non-wide symlinks to
directories fail over SMB3.
Mark as knownfail.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12860
Signed-off-by: Jeremy Allison <jra at samba.org>
---
selftest/knownfail | 1 +
selftest/target/Samba3.pm | 8 +++++
source3/script/tests/test_smbclient_s3.sh | 55 +++++++++++++++++++++++++++++++
3 files changed, 64 insertions(+)
diff --git a/selftest/knownfail b/selftest/knownfail
index c6047c85445..9f9e9761465 100644
--- a/selftest/knownfail
+++ b/selftest/knownfail
@@ -335,3 +335,4 @@
# We currently don't send referrals for LDAP modify of non-replicated attrs
^samba4.ldap.rodc.python\(rodc\).__main__.RodcTests.test_modify_nonreplicated.*
^samba4.ldap.rodc_rwdc.python.*.__main__.RodcRwdcTests.test_change_password_reveal_on_demand_kerberos
+^samba3.blackbox.smbclient_s3.*follow local symlinks.*
diff --git a/selftest/target/Samba3.pm b/selftest/target/Samba3.pm
index d93d98e3af3..6854d7c0ecd 100755
--- a/selftest/target/Samba3.pm
+++ b/selftest/target/Samba3.pm
@@ -1355,6 +1355,9 @@ sub provision($$$$$$$$$)
my $nosymlinks_shrdir="$shrdir/nosymlinks";
push(@dirs,$nosymlinks_shrdir);
+ my $local_symlinks_shrdir="$shrdir/local_symlinks";
+ push(@dirs,$local_symlinks_shrdir);
+
# this gets autocreated by winbindd
my $wbsockdir="$prefix_abs/winbindd";
@@ -1976,6 +1979,11 @@ sub provision($$$$$$$$$)
path = $nosymlinks_shrdir
follow symlinks = no
+[local_symlinks]
+ copy = tmp
+ path = $local_symlinks_shrdir
+ follow symlinks = yes
+
[kernel_oplocks]
copy = tmp
kernel oplocks = yes
diff --git a/source3/script/tests/test_smbclient_s3.sh b/source3/script/tests/test_smbclient_s3.sh
index 050dd81623e..1c5a13d110f 100755
--- a/source3/script/tests/test_smbclient_s3.sh
+++ b/source3/script/tests/test_smbclient_s3.sh
@@ -1215,6 +1215,57 @@ EOF
fi
}
+# Test we can follow normal symlinks.
+# Bug: https://bugzilla.samba.org/show_bug.cgi?id=12860
+# Note - this needs to be tested over SMB3, not SMB1.
+
+test_local_symlinks()
+{
+# Setup test dirs.
+ LOCAL_RAWARGS="${CONFIGURATION} -mSMB3"
+ LOCAL_ADDARGS="${LOCAL_RAWARGS} $*"
+
+ test_dir="$LOCAL_PATH/local_symlinks/test"
+
+ slink_name="$test_dir/sym_name"
+ slink_target_dir="$test_dir/dir1"
+
+ rm -rf $test_dir
+
+ mkdir -p $test_dir
+ mkdir $slink_target_dir
+ ln -s $slink_target_dir $slink_name
+
+# Can we cd into the symlink name and ls ?
+ tmpfile=$PREFIX/smbclient_interactive_prompt_commands
+ cat > $tmpfile <<EOF
+cd test\\sym_name
+ls
+quit
+EOF
+ cmd='CLI_FORCE_INTERACTIVE=yes $SMBCLIENT "$@" -U$USERNAME%$PASSWORD //$SERVER/local_symlinks -I $SERVER_IP $LOCAL_ADDARGS < $tmpfile 2>&1'
+ eval echo "$cmd"
+ out=`eval $cmd`
+ ret=$?
+ rm -f $tmpfile
+
+ if [ $ret -ne 0 ] ; then
+ echo "$out"
+ echo "failed accessing local_symlinks with error $ret"
+ false
+ return
+ fi
+
+ echo "$out" | grep 'NT_STATUS_'
+ ret=$?
+ if [ $ret -eq 0 ] ; then
+ echo "$out"
+ echo "failed - got an NT_STATUS error"
+ false
+ return
+ fi
+}
+
test_server_os_message()
{
tmpfile=$PREFIX/smbclient_interactive_prompt_commands
@@ -1348,6 +1399,10 @@ testit "follow symlinks = no" \
test_nosymlinks || \
failed=`expr $failed + 1`
+testit "follow local symlinks" \
+ test_local_symlinks || \
+ failed=`expr $failed + 1`
+
testit "server os message" \
test_server_os_message || \
failed=`expr $failed + 1`
--
2.11.0
>From 7a852618ceb3e8c8929a8c325fe105d755a37a06 Mon Sep 17 00:00:00 2001
From: Daniel Kobras <d.kobras at science-computing.de>
Date: Fri, 23 Jun 2017 15:39:21 +0200
Subject: [PATCH 2/2] 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 at science-computing.de>
Reviewed-by: Jeremy Allison <jra at samba.org>
---
selftest/knownfail | 1 -
source3/smbd/open.c | 22 +++++++++++++++++++++-
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/selftest/knownfail b/selftest/knownfail
index 9f9e9761465..c6047c85445 100644
--- a/selftest/knownfail
+++ b/selftest/knownfail
@@ -335,4 +335,3 @@
# We currently don't send referrals for LDAP modify of non-replicated attrs
^samba4.ldap.rodc.python\(rodc\).__main__.RodcTests.test_modify_nonreplicated.*
^samba4.ldap.rodc_rwdc.python.*.__main__.RodcRwdcTests.test_change_password_reveal_on_demand_kerberos
-^samba3.blackbox.smbclient_s3.*follow local symlinks.*
diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index e68e2ace850..382b16a97c5 100644
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -581,7 +581,18 @@ 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;
@@ -602,6 +613,15 @@ 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);
}
--
2.11.0
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