The branch, v4-4-test has been updated via 0839f6c s3: Test for CVE-2017-2619 regression with "follow symlinks = no" - part 2 via ed694d0 s3: smbd: Fix "follow symlink = no" regression part 2. via 8e3e969 s3: smbd: Fix "follow symlink = no" regression part 2. via 9a5be8b s3: Fixup test for CVE-2017-2619 regression with "follow symlinks = no" via 161a078 s3: Test for CVE-2017-2619 regression with "follow symlinks = no". via 4a6d828e s3: smbd: Fix incorrect logic exposed by fix for the security bug 12496 (CVE-2017-2619). from 2e00feb s3: locking: Update oplock optimization for the leases era !
https://git.samba.org/?p=samba.git;a=shortlog;h=v4-4-test - Log ----------------------------------------------------------------- commit 0839f6c6f4005f217475c70ba60b75bbd72e608e Author: Jeremy Allison <j...@samba.org> Date: Mon Mar 27 22:10:29 2017 -0700 s3: Test for CVE-2017-2619 regression with "follow symlinks = no" - part 2 Add tests for regular access. BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721 Signed-off-by: Jeremy Allison <j...@samba.org> Reviewed-by: Ralph Boehme <s...@samba.org> Autobuild-User(master): Ralph Böhme <s...@samba.org> Autobuild-Date(master): Tue Mar 28 17:05:27 CEST 2017 on sn-devel-144 (cherry picked from commit 4e734fcd1bf82c08aa303ce44e9735acccffcf06) Autobuild-User(v4-4-test): Karolin Seeger <ksee...@samba.org> Autobuild-Date(v4-4-test): Wed Mar 29 13:57:56 CEST 2017 on sn-devel-144 commit ed694d068081d4849e558fabc0c42085c64ee3b5 Author: Jeremy Allison <j...@samba.org> Date: Mon Mar 27 17:09:38 2017 -0700 s3: smbd: Fix "follow symlink = no" regression part 2. Use the cwd_name parameter to reconstruct the original client name for symlink testing. BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721 Signed-off-by: Jeremy Allison <j...@samba.org> Reviewed-by: Ralph Boehme <s...@samba.org> (cherry picked from commit e182a4d39e86c9694e255efdf6ee2ea3ccb9af4a) commit 8e3e969eeddc542385d0ccee793f71c12e8fd4b6 Author: Jeremy Allison <j...@samba.org> Date: Mon Mar 27 17:04:58 2017 -0700 s3: smbd: Fix "follow symlink = no" regression part 2. Add an extra paramter to cwd_name to check_reduced_name(). If cwd_name == NULL then fname is a client given path relative to the root path of the share. If cwd_name != NULL then fname is a client given path relative to cwd_name. cwd_name is relative to the root path of the share. Not yet used, logic added in the next commit. BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721 Signed-off-by: Jeremy Allison <j...@samba.org> Reviewed-by: Ralph Boehme <s...@samba.org> (cherry picked from commit 83e30cb48859b412b76572b6a3ba84d8fde167af) commit 9a5be8b68ba38e0d98329c44d0d5c6d4579c9bf5 Author: Jeremy Allison <j...@samba.org> Date: Mon Mar 27 22:07:50 2017 -0700 s3: Fixup test for CVE-2017-2619 regression with "follow symlinks = no" Use correct bash operators (not string operators). Add missing "return". BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721 Signed-off-by: Jeremy Allison <j...@samba.org> Reviewed-by: Ralph Boehme <s...@samba.org> (cherry picked from commit 037297a1c50e90a0092e3b94f472623f41ccc015) commit 161a078f550f4c9a50a8f42e29b1f27de689362b Author: Jeremy Allison <j...@samba.org> Date: Mon Mar 27 11:48:25 2017 -0700 s3: Test for CVE-2017-2619 regression with "follow symlinks = no". BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721 Signed-off-by: Jeremy Allison <j...@samba.org> Reviewed-by: Uri Simchoni <u...@samba.org> Back-ported from commit 782172a9bef0040981d20e49519b13dd744df6a0 commit 4a6d828e8f230ab6578c73bba7eec06ece6f7fac Author: Jeremy Allison <j...@samba.org> Date: Mon Mar 27 10:46:47 2017 -0700 s3: smbd: Fix incorrect logic exposed by fix for the security bug 12496 (CVE-2017-2619). In a UNIX filesystem, the names "." and ".." by definition can *never* be symlinks - they are already reserved names. BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721 Signed-off-by: Jeremy Allison <j...@samba.org> Reviewed-by: Uri Simchoni <u...@samba.org> (cherry picked from commit ae17bebd250bdde5614b2ac17e53512f19fe9b68) ----------------------------------------------------------------------- Summary of changes: selftest/target/Samba3.pm | 7 ++ source3/script/tests/test_smbclient_s3.sh | 111 ++++++++++++++++++++++++++++++ source3/smbd/filename.c | 2 +- source3/smbd/open.c | 2 +- source3/smbd/proto.h | 4 +- source3/smbd/vfs.c | 40 ++++++++++- 6 files changed, 160 insertions(+), 6 deletions(-) Changeset truncated at 500 lines: diff --git a/selftest/target/Samba3.pm b/selftest/target/Samba3.pm index 619ae1e..938c459 100755 --- a/selftest/target/Samba3.pm +++ b/selftest/target/Samba3.pm @@ -1191,6 +1191,9 @@ sub provision($$$$$$$$) my $shadow_shrdir="$shadow_basedir/share"; push(@dirs,$shadow_shrdir); + my $nosymlinks_shrdir="$shrdir/nosymlinks"; + push(@dirs,$nosymlinks_shrdir); + # this gets autocreated by winbindd my $wbsockdir="$prefix_abs/winbindd"; my $wbsockprivdir="$lockdir/winbindd_privileged"; @@ -1717,6 +1720,10 @@ sub provision($$$$$$$$) copy = tmp acl_xattr:ignore system acls = yes acl_xattr:default acl style = windows +[nosymlinks] + copy = tmp + path = $nosymlinks_shrdir + follow symlinks = no [kernel_oplocks] copy = tmp kernel oplocks = yes diff --git a/source3/script/tests/test_smbclient_s3.sh b/source3/script/tests/test_smbclient_s3.sh index 5e3db5d..0694e1b 100755 --- a/source3/script/tests/test_smbclient_s3.sh +++ b/source3/script/tests/test_smbclient_s3.sh @@ -1071,6 +1071,113 @@ done LOGDIR=$(mktemp -d ${PREFIX}/${LOGDIR_PREFIX}_XXXXXX) +# Test follow symlinks can't access symlinks +test_nosymlinks() +{ +# Setup test dirs. + slink_name="$LOCAL_PATH/nosymlinks/source" + slink_target="$LOCAL_PATH/nosymlinks/target" + mkdir_target="$LOCAL_PATH/nosymlinks/a" + dir1="$LOCAL_PATH/nosymlinks/foo" + dir2="$LOCAL_PATH/nosymlinks/foo/bar" + get_target="$LOCAL_PATH/nosymlinks/foo/bar/testfile" + + rm -f $slink_target + rm -f $slink_name + rm -rf $mkdir_target + rm -rf $dir1 + + touch $slink_target + ln -s $slink_target $slink_name + + mkdir $dir1 + mkdir $dir2 + touch $get_target + +# Getting a file through a symlink name should fail. + tmpfile=$PREFIX/smbclient_interactive_prompt_commands + cat > $tmpfile <<EOF +get source +quit +EOF + cmd='CLI_FORCE_INTERACTIVE=yes $SMBCLIENT "$@" -U$USERNAME%$PASSWORD //$SERVER/nosymlinks -I $SERVER_IP $ADDARGS < $tmpfile 2>&1' + eval echo "$cmd" + out=`eval $cmd` + ret=$? + rm -f $tmpfile + + if [ $ret -ne 0 ] ; then + echo "$out" + echo "failed accessing nosymlinks with error $ret" + false + return + fi + + echo "$out" | grep 'NT_STATUS_ACCESS_DENIED' + ret=$? + if [ $ret -ne 0 ] ; then + echo "$out" + echo "failed - should get NT_STATUS_ACCESS_DENIED getting \\nosymlinks\\source" + false + return + fi + +# But we should be able to create and delete directories. + cat > $tmpfile <<EOF +mkdir a +mkdir a\\b +quit +EOF + cmd='CLI_FORCE_INTERACTIVE=yes $SMBCLIENT "$@" -U$USERNAME%$PASSWORD //$SERVER/nosymlinks -I $SERVER_IP $ADDARGS < $tmpfile 2>&1' + eval echo "$cmd" + out=`eval $cmd` + ret=$? + rm -f $tmpfile + + if [ $ret -ne 0 ] ; then + echo "$out" + echo "failed accessing nosymlinks with error $ret" + false + return + fi + + echo "$out" | grep 'NT_STATUS' + ret=$? + if [ $ret -eq 0 ] ; then + echo "$out" + echo "failed - NT_STATUS_XXXX doing mkdir a; mkdir a\\b on \\nosymlinks" + false + fi + +# Ensure regular file/directory access also works. + cat > $tmpfile <<EOF +cd foo\\bar +ls +get testfile - +quit +EOF + cmd='CLI_FORCE_INTERACTIVE=yes $SMBCLIENT "$@" -U$USERNAME%$PASSWORD //$SERVER/nosymlinks -I $SERVER_IP $ADDARGS < $tmpfile 2>&1' + eval echo "$cmd" + out=`eval $cmd` + ret=$? + rm -f $tmpfile + + if [ $ret -ne 0 ] ; then + echo "$out" + echo "failed accessing nosymlinks with error $ret" + false + return + fi + + echo "$out" | grep 'NT_STATUS' + ret=$? + if [ $ret -eq 0 ] ; then + echo "$out" + echo "failed - NT_STATUS_XXXX doing cd foo\\bar; get testfile on \\nosymlinks" + false + return + fi +} testit "smbclient -L $SERVER_IP" $SMBCLIENT -L $SERVER_IP -N -p 139 || failed=`expr $failed + 1` testit "smbclient -L $SERVER -I $SERVER_IP" $SMBCLIENT -L $SERVER -I $SERVER_IP -N -p 139 -c quit || failed=`expr $failed + 1` @@ -1155,6 +1262,10 @@ testit "Ensure widelinks are restricted" \ test_widelinks || \ failed=`expr $failed + 1` +testit "follow symlinks = no" \ + test_nosymlinks || \ + failed=`expr $failed + 1` + testit "rm -rf $LOGDIR" \ rm -rf $LOGDIR || \ failed=`expr $failed + 1` diff --git a/source3/smbd/filename.c b/source3/smbd/filename.c index 046ce9c..9f72f99 100644 --- a/source3/smbd/filename.c +++ b/source3/smbd/filename.c @@ -1240,7 +1240,7 @@ NTSTATUS check_name(connection_struct *conn, const char *name) } if (!lp_widelinks(SNUM(conn)) || !lp_follow_symlinks(SNUM(conn))) { - status = check_reduced_name(conn,name); + status = check_reduced_name(conn, NULL, name); if (!NT_STATUS_IS_OK(status)) { DEBUG(5,("check_name: name %s failed with %s\n",name, nt_errstr(status))); diff --git a/source3/smbd/open.c b/source3/smbd/open.c index 0b66487..f19af87 100644 --- a/source3/smbd/open.c +++ b/source3/smbd/open.c @@ -546,7 +546,7 @@ static int non_widelink_open(struct connection_struct *conn, } /* Ensure the relative path is below the share. */ - status = check_reduced_name(conn, final_component); + status = check_reduced_name(conn, parent_dir, final_component); if (!NT_STATUS_IS_OK(status)) { saved_errno = map_errno_from_nt_status(status); goto out; diff --git a/source3/smbd/proto.h b/source3/smbd/proto.h index ebccdb9..9103e6e 100644 --- a/source3/smbd/proto.h +++ b/source3/smbd/proto.h @@ -1197,7 +1197,9 @@ const char *vfs_readdirname(connection_struct *conn, void *p, SMB_STRUCT_STAT *sbuf, char **talloced); int vfs_ChDir(connection_struct *conn, const char *path); char *vfs_GetWd(TALLOC_CTX *ctx, connection_struct *conn); -NTSTATUS check_reduced_name(connection_struct *conn, const char *fname); +NTSTATUS check_reduced_name(connection_struct *conn, + const char *cwd_name, + const char *fname); NTSTATUS check_reduced_name_with_privilege(connection_struct *conn, const char *fname, struct smb_request *smbreq); diff --git a/source3/smbd/vfs.c b/source3/smbd/vfs.c index 93726bd..254337f 100644 --- a/source3/smbd/vfs.c +++ b/source3/smbd/vfs.c @@ -1149,11 +1149,20 @@ NTSTATUS check_reduced_name_with_privilege(connection_struct *conn, /******************************************************************* Reduce a file name, removing .. elements and checking that it is below dir in the heirachy. This uses realpath. + + If cwd_name == NULL then fname is a client given path relative + to the root path of the share. + + If cwd_name != NULL then fname is a client given path relative + to cwd_name. cwd_name is relative to the root path of the share. ********************************************************************/ -NTSTATUS check_reduced_name(connection_struct *conn, const char *fname) +NTSTATUS check_reduced_name(connection_struct *conn, + const char *cwd_name, + const char *fname) { char *resolved_name = NULL; + char *new_fname = NULL; bool allow_symlinks = true; bool allow_widelinks = false; @@ -1277,8 +1286,11 @@ NTSTATUS check_reduced_name(connection_struct *conn, const char *fname) /* fname can't have changed in resolved_path. */ const char *p = &resolved_name[rootdir_len]; - /* *p can be '\0' if fname was "." */ - if (*p == '\0' && ISDOT(fname)) { + /* + * UNIX filesystem semantics, names consisting + * only of "." or ".." CANNOT be symlinks. + */ + if (ISDOT(fname) || ISDOTDOT(fname)) { goto out; } @@ -1292,11 +1304,32 @@ NTSTATUS check_reduced_name(connection_struct *conn, const char *fname) } p++; + + /* + * If cwd_name is present and not ".", + * then fname is relative to that, not + * the root of the share. Make sure the + * path we check is the one the client + * sent (cwd_name+fname). + */ + if (cwd_name != NULL && !ISDOT(cwd_name)) { + new_fname = talloc_asprintf(talloc_tos(), + "%s/%s", + cwd_name, + fname); + if (new_fname == NULL) { + SAFE_FREE(resolved_name); + return NT_STATUS_NO_MEMORY; + } + fname = new_fname; + } + if (strcmp(fname, p)!=0) { DEBUG(2, ("check_reduced_name: Bad access " "attempt: %s is a symlink to %s\n", fname, p)); SAFE_FREE(resolved_name); + TALLOC_FREE(new_fname); return NT_STATUS_ACCESS_DENIED; } } @@ -1306,6 +1339,7 @@ NTSTATUS check_reduced_name(connection_struct *conn, const char *fname) DBG_INFO("%s reduced to %s\n", fname, resolved_name); SAFE_FREE(resolved_name); + TALLOC_FREE(new_fname); return NT_STATUS_OK; } -- Samba Shared Repository