[PATCH] disable lomount and miniterm by default

[PATCH] disable lomount and miniterm by default

[Ian Jackson]

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lomount is a tool which reads and parses a partition table in a disk
image block device and then uses mount -o ...offset=... to mount it.
This is not an ideal approach.  For example, if the intended
filesystem has corrupted metadata the kernel's filesystem driver may
start to write outside of the intended region.  This might even be
exploitable in some perverse circumstances.

Nowadays people wanting to do this should use kpartx, which uses
devmapper to create appropriate range mappings.  So lomount should be
disabled.

miniterm may well be useful but it is a clone-and-hack of an upstream
project and is currently built but not installed by default, partly
because it doesn't make sense to install on the dom0 which it might be
trying to debug.

It is probably useful to retain these two programs in the source tree
but IMO they should no longer be built by default.

The attached patch does these things:
 * CONFIG_LOMOUNT and CONFIG_MINITERM in Config.mk
   can enable and disable these programs
 * They are disabled by default
 * If CONFIG_MINITERM=y it is still built but not installed.
   make -C tools/misc/miniterm install  will install it.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>


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diff -r 2491691e3e69 Config.mk
--- a/Config.mk	Sat Dec 29 17:57:47 2007 +0000
+++ b/Config.mk	Wed Jan 16 16:46:06 2008 +0000
@@ -90,5 +90,7 @@ VTPM_TOOLS         ?= n
 VTPM_TOOLS         ?= n
 LIBXENAPI_BINDINGS ?= n
 PYTHON_TOOLS       ?= y
+CONFIG_MINITERM		?= n
+CONFIG_LOMOUNT		?= n
 
 -include $(XEN_ROOT)/.config
diff -r 2491691e3e69 tools/misc/Makefile
--- a/tools/misc/Makefile	Sat Dec 29 17:57:47 2007 +0000
+++ b/tools/misc/Makefile	Wed Jan 16 16:51:13 2008 +0000
@@ -13,6 +13,10 @@ TARGETS-$(CONFIG_X86) += xen-detect
 TARGETS-$(CONFIG_X86) += xen-detect
 TARGETS := $(TARGETS-y)
 
+SUBDIRS-$(CONFIG_LOMOUNT) += lomount
+SUBDIRS-$(CONFIG_MINITERM) += miniterm
+SUBDIRS := $(SUBDIRS-y)
+
 INSTALL_BIN  = $(TARGETS) xencons
 INSTALL_SBIN = netfix xm xen-bugtool xen-python-path xend xenperf xsview
 
@@ -21,8 +25,7 @@ all: build
 
 .PHONY: build
 build: $(TARGETS)
-	$(MAKE) -C miniterm
-	$(MAKE) -C lomount
+	set -e; for d in $(SUBDIRS); do $(MAKE) -C $$d; done
 
 .PHONY: install
 install: build
@@ -30,15 +33,12 @@ install: build
 	[ -d $(DESTDIR)/usr/sbin ] || $(INSTALL_DIR) $(DESTDIR)/usr/sbin
 	$(INSTALL_PROG) $(INSTALL_BIN) $(DESTDIR)/usr/bin
 	$(INSTALL_PROG) $(INSTALL_SBIN) $(DESTDIR)/usr/sbin
-	$(MAKE) -C lomount install
-#       No sense in installing miniterm on the Xen box.
-#	$(MAKE) -C miniterm install
+	set -e; for d in $(SUBDIRS); do $(MAKE) -C $$d install-recurse; done
 
 .PHONY: clean
 clean:
 	$(RM) *.o $(TARGETS) *~
-	$(MAKE) -C miniterm clean
-	$(MAKE) -C lomount clean
+	set -e; for d in $(SUBDIRS); do $(MAKE) -C $$d clean; done
 
 %.o: %.c $(HDRS) Makefile
 	$(CC) -c $(CFLAGS) -o $@ $<
diff -r 2491691e3e69 tools/misc/lomount/Makefile
--- a/tools/misc/lomount/Makefile	Sat Dec 29 17:57:47 2007 +0000
+++ b/tools/misc/lomount/Makefile	Wed Jan 16 16:46:06 2008 +0000
@@ -15,7 +15,7 @@ build: $(BIN)
 build: $(BIN)
 
 .PHONY: install
-install: build
+install install-recurse: build
 	$(INSTALL_PROG) $(BIN) $(SCRIPTS) $(DESTDIR)/usr/bin
 
 .PHONY: clean
diff -r 2491691e3e69 tools/misc/miniterm/Makefile
--- a/tools/misc/miniterm/Makefile	Sat Dec 29 17:57:47 2007 +0000
+++ b/tools/misc/miniterm/Makefile	Wed Jan 16 16:46:06 2008 +0000
@@ -11,6 +11,9 @@ install: all
 	[ -d $(DESTDIR)/usr/bin ] || $(INSTALL_DIR) $(DESTDIR)/usr/bin
 	$(INSTALL_PROG) $(TARGET) $(DESTDIR)/usr/bin
 
+.PHONY: install-recurse
+	: No sense in installing miniterm on the Xen box.
+
 .PHONY: clean
 clean:
 	$(RM) *.o $(TARGET) *~

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Re: [PATCH] disable lomount and miniterm by default

[Daniel P. Berrange]

On Wed, Jan 16, 2008 at 05:01:32PM +0000, Ian Jackson wrote:
Content-Description: message body text
> lomount is a tool which reads and parses a partition table in a disk
> image block device and then uses mount -o ...offset=... to mount it.
> This is not an ideal approach.  For example, if the intended
> filesystem has corrupted metadata the kernel's filesystem driver may
> start to write outside of the intended region.  This might even be
> exploitable in some perverse circumstances.
> 
> Nowadays people wanting to do this should use kpartx, which uses
> devmapper to create appropriate range mappings.  So lomount should be
> disabled.

+1 for this.

> miniterm may well be useful but it is a clone-and-hack of an upstream
> project and is currently built but not installed by default, partly
> because it doesn't make sense to install on the dom0 which it might be
> trying to debug.

Any idea of what the changes are wrt to upstream ?  If they're useful
we should try and get them upstream.

While on the subject of tools, I'm puzelled why Xen has created custom tools 
qcow-create, qcow2raw and img2qcow,  when they are less functional than
the existing 'qemu-img' tool that comes as part of the QEMU codebase

Dan.
-- 
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Re: [PATCH] disable lomount and miniterm by default

[Ian Jackson]

Daniel P. Berrange writes ("Re: [Xen-devel] [PATCH] disable lomount and miniterm by default"):
> On Wed, Jan 16, 2008 at 05:01:32PM +0000, Ian Jackson wrote:
> > miniterm may well be useful but it is a clone-and-hack of an upstream
> > project and is currently built but not installed by default, partly
> > because it doesn't make sense to install on the dom0 which it might be
> > trying to debug.
> 
> Any idea of what the changes are wrt to upstream ?  If they're useful
> we should try and get them upstream.

The original author wrote it as example code for a book, rather than
as a software project which might be generally distributed and
updated.  The internet seems full of a huge variety of clone-and-hack
copies of miniterm as a result.

> While on the subject of tools, I'm puzelled why Xen has created custom tools 
> qcow-create, qcow2raw and img2qcow,  when they are less functional than
> the existing 'qemu-img' tool that comes as part of the QEMU codebase

I'm afraid this is far from clear.  If no-one knows why then we should
arrange to build qemu-img and and replace the references, so we can
deprecate our own less-sane tools.

Ian.