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nmap: add option to build/install ncat

PATCH New Carlos Santos 5 participants 8 messages Oct 12, 2017 – Apr 2, 2018

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#0 lore raw

PATCH v4 1/1 nmap: add option to build/install ncat

Ncat is a much-improved reimplementation of the venerable Netcat and is compatible with uClibc and musl. It provides features not available in the ancient GNU netcat and its Busybox double like IPv6, proxies, and Unix sockets.

Tha nmap package now installs ncat if the BR2_PACKAGE_NMAP_NCAT option is selected. The other programs (nmap, ndiff, etc.) are chosen via the BR2_PACKAGE_NMAP_NMAP option.

We symlink 'nc' to ncat if neiter netcat nor netcat-openbsd is selected, even though ncat does not have the same interface as netcat-openbsd. However, since Fedora/RHEL install nmap-ncat as 'nc', it can be assumed that packages that depend on 'nc' know how to deal with this diversity. For example, the virt-manager package does that. Also user-supplied scripts can be assumed to do the right thing, since the user also selects whether nmap-ncat, netcat or netcat-openbsd is installed.

---
Changes v1->v2:
- Add dependens on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS, like netcat does
- Remove forced dependence on busybox, since its installation script does not override existing programs.
Changes v2->v3:
- Use a better logic to select either ncat tools, nmap or both, as suggested by Arnout Vandecappelle and Thomas Petazzoni.
- Add a prominent comment about the symlink to 'nc', as suggested by Arnout.
Changes v3->v4:
- Restore forced dependence on busybox, since it may be necessary if packages become built in parallel, leading to a race condition on the creation of the "nc" link.

---
 package/nmap/Config.in | 27 ++++++++++++++++++++++++++-
 package/nmap/nmap.mk   | 38 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 62 insertions(+), 3 deletions(-)
package/nmap/Config.in +26 -1
index 79f587afd1..1843bb6ade 100644
@@ -4,6 +4,12 @@ config BR2_PACKAGE_NMAP
 	depends on BR2_USE_MMU # fork()
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_LIBPCAP
+	select BR2_PACKAGE_NMAP_NMAP if !BR2_PACKAGE_NMAP_NCAT
+
+if  BR2_PACKAGE_NMAP
+
+config BR2_PACKAGE_NMAP_NMAP
+	bool "install nmap tools"
 	select BR2_PACKAGE_PCRE
 	help
 	  Nmap ("Network Mapper") is a free and open source (license)
@@ -11,6 +17,25 @@ config BR2_PACKAGE_NMAP
 
 	  http://nmap.org
 
-comment "nmap needs a toolchain w/ C++, threads"
+config BR2_PACKAGE_NMAP_NCAT
+	bool "install ncat"
+	depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
+	help
+	  Ncat is a feature-packed networking utility which reads and
+	  writes data across networks from the command line. Ncat was
+	  written for the Nmap Project as a much-improved
+	  reimplementation of the venerable Netcat.
+
+	  If symlink to "nc" is installed if neither netcat or
+	  netcat-openbsd is selected.
+
+comment "a symlink from ncat to 'nc' will be installed"
+	depends on BR2_PACKAGE_NMAP_NCAT
+	depends on !BR2_PACKAGE_NETCAT
+	depends on !BR2_PACKAGE_NETCAT_OPENBSD
+
+endif
+
+comment "nmap-nmap needs a toolchain w/ C++, threads"
 	depends on BR2_USE_MMU
 	depends on !(BR2_INSTALL_LIBSTDCPP && BR2_TOOLCHAIN_HAS_THREADS)
package/nmap/nmap.mk +36 -2
index 9db06d1455..d4c9acde07 100644
@@ -7,13 +7,19 @@
 NMAP_VERSION = 7.60
 NMAP_SITE = https://nmap.org/dist
 NMAP_SOURCE = nmap-$(NMAP_VERSION).tar.bz2
-NMAP_DEPENDENCIES = libpcap pcre
+NMAP_DEPENDENCIES = libpcap
 NMAP_CONF_OPTS = --without-liblua --without-zenmap \
 	--with-libdnet=included --with-liblinear=included \
-	--with-libpcre="$(STAGING_DIR)/usr" --without-ncat
+	--with-libpcre="$(STAGING_DIR)/usr"
 NMAP_LICENSE = GPL-2.0
 NMAP_LICENSE_FILES = COPYING
 
+# Ensure Busybox gets built/installed before, so that this package
+# overrides Busybox nc.
+ifeq ($(BR2_PACKAGE_BUSYBOX)$(BR2_PACKAGE_NMAP_NCAT),yy)
+NMAP_DEPENDENCIES += busybox
+endif
+
 # needed by libpcap
 NMAP_LIBS_FOR_STATIC_LINK += `$(STAGING_DIR)/usr/bin/pcap-config --static --additional-libs`
 
@@ -43,6 +49,10 @@ else
 NMAP_CONF_OPTS += --without-openssl
 endif
 
+ifeq ($(BR2_PACKAGE_NMAP_NMAP),y)
+
+NMAP_DEPENDENCIES += pcre
+
 # ndiff only works with python2.x
 ifeq ($(BR2_PACKAGE_PYTHON),y)
 NMAP_DEPENDENCIES += python
@@ -50,4 +60,28 @@ else
 NMAP_CONF_OPTS += --without-ndiff
 endif
 
+ifeq ($(BR2_PACKAGE_NMAP_NCAT),)
+NMAP_CONF_OPTS += --without-ncat
+endif
+
+else # only ncat
+
+NMAP_CONF_OPTS += --without-ndiff --without-zenmap --without-nping --without-nmap-update
+define NMAP_BUILD_CMDS
+	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) build-ncat
+endef
+define NMAP_INSTALL_TARGET_CMDS
+	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) DESTDIR=$(TARGET_DIR) install-ncat
+endef
+
+endif
+
+# Add a symlink to "nc" if none of the competing netcats is selected
+ifeq ($(BR2_PACKAGE_NMAP_NCAT):$(BR2_PACKAGE_NETCAT)$(BR2_PACKAGE_NETCAT_OPENBSD),y:)
+define NMAP_INSTALL_NCAT_SYMLINK
+        ln -fs ncat $(TARGET_DIR)/usr/bin/nc
+endef
+NMAP_POST_INSTALL_TARGET_HOOKS += NMAP_INSTALL_NCAT_SYMLINK
+endif
+
 $(eval $(autotools-package))
Signature · 1 line
2.13.6
#1 lore raw

PATCH 1/1 netcat: add forced dependence on BusyBox

It may be necessary if packages become built in parallel, leading to a race condition on the creation of the "nc" link. Moreover, netcat is as shy as BusyBox and would not override an existing file/link, so we must remove $(TARGET_DIR)/usr/bin/nc in advance.

Of course this still leaves a race conditon if other netcat competitors but we must assume thet the user is a grown-up person who knows what is doing.

---
 package/netcat/netcat.mk | 11 +++++++++++
 1 file changed, 11 insertions(+)
package/netcat/netcat.mk +11 -0
index eb7ddcac27..c032eea56d 100644
@@ -9,4 +9,15 @@ NETCAT_SITE = http://downloads.sourceforge.net/project/netcat/netcat/$(NETCAT_VE
 NETCAT_LICENSE = GPL-2.0+
 NETCAT_LICENSE_FILES = COPYING
 
+# Ensure Busybox gets built/installed before, so that this package
+# overrides Busybox nc. We must remove an existing file/link because
+# netcat is as shy as Busybox and would not override existing files.
+ifeq ($(BR2_PACKAGE_BUSYBOX),y)
+NETCAT_DEPENDENCIES += busybox
+define NETCAT_RMOVE_NC_LINK
+	rm -f $(TARGET_DIR)/usr/bin/nc
+endef
+NETCAT_PRE_INSTALL_TARGET_HOOKS += NETCAT_RMOVE_NC_LINK
+endif
+
 $(eval $(autotools-package))
Signature · 1 line
2.13.6
#2 lore raw

PATCH 1/1 netcat: add forced dependence on BusyBox

Hi Carlos,

Le 12/10/2017 ? 17:14, Carlos Santos a ?crit?:

Quoted 8 lines

It may be necessary if packages become built in parallel, leading to a race condition on the creation of the "nc" link. Moreover, netcat is as shy as BusyBox and would not override an existing file/link, so we must remove $(TARGET_DIR)/usr/bin/nc in advance.

Of course this still leaves a race conditon if other netcat competitors but we must assume thet the user is a grown-up person who knows what is doing.

It seems you are using a custom busybox config file because the netcat applet is disabled by default.

I'm agree, the dependency on busybox is missing but the TARGET_HOOKS doesn't seems necessary. I removed it and netcat package is able to override the busybox symlink.

/usr/bin/install -c netcat output/target/usr/bin/netcat

Maybe we should check if other packages depending on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS have a dependency on busybox.

Best regards,
Romain

Quoted 27 lines
---
 package/netcat/netcat.mk | 11 +++++++++++
 1 file changed, 11 insertions(+)
package/netcat/netcat.mk +11 -0
index eb7ddcac27..c032eea56d 100644
@@ -9,4 +9,15 @@ NETCAT_SITE = http://downloads.sourceforge.net/project/netcat/netcat/$(NETCAT_VE
 NETCAT_LICENSE = GPL-2.0+
 NETCAT_LICENSE_FILES = COPYING
 
+# Ensure Busybox gets built/installed before, so that this package
+# overrides Busybox nc. We must remove an existing file/link because
+# netcat is as shy as Busybox and would not override existing files.
+ifeq ($(BR2_PACKAGE_BUSYBOX),y)
+NETCAT_DEPENDENCIES += busybox
+define NETCAT_RMOVE_NC_LINK
+	rm -f $(TARGET_DIR)/usr/bin/nc
+endef
+NETCAT_PRE_INSTALL_TARGET_HOOKS += NETCAT_RMOVE_NC_LINK
+endif
+
 $(eval $(autotools-package))
#3 lore raw

PATCH 1/1 netcat: add forced dependence on BusyBox

Quoted 12 lines · Romain Naour

Hi Carlos,

Le 12/10/2017 ? 17:14, Carlos Santos a ?crit?:

Quoted 8 lines

It may be necessary if packages become built in parallel, leading to a race condition on the creation of the "nc" link. Moreover, netcat is as shy as BusyBox and would not override an existing file/link, so we must remove $(TARGET_DIR)/usr/bin/nc in advance.

Of course this still leaves a race conditon if other netcat competitors but we must assume thet the user is a grown-up person who knows what is doing.

Quoted 8 lines

It seems you are using a custom busybox config file because the netcat applet is disabled by default.

I'm agree, the dependency on busybox is missing but the TARGET_HOOKS doesn't seems necessary. I removed it and netcat package is able to override the busybox symlink.

/usr/bin/install -c netcat output/target/usr/bin/netcat

And anyway, in the context of PPS we will eventually have to reverse the
busybox dependencies, i.e. busybox will depend on netcat.

Quoted 2 lines

Maybe we should check if other packages depending on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS have a dependency on busybox.

check-uniq-files should cover this.

Regards,
Arnout

Quoted 37 lines

Best regards,
Romain

Quoted 17 lines
---
 package/netcat/netcat.mk | 11 +++++++++++
 1 file changed, 11 insertions(+)
package/netcat/netcat.mk +2 -0
index eb7ddcac27..c032eea56d 100644
@@ -9,4 +9,15 @@ NETCAT_SITE = http://downloads.sourceforge.net/project/netcat/netcat/$(NETCAT_VE
 NETCAT_LICENSE = GPL-2.0+
 NETCAT_LICENSE_FILES = COPYING
 
+# Ensure Busybox gets built/installed before, so that this package
+# overrides Busybox nc. We must remove an existing file/link because

package/netcat/netcat.mk NETCAT_SITE = http://downloads.sourceforge.net/project/netcat/netcat/$(NETCAT_VE · line 23

Quoted 10 lines
package/netcat/netcat.mk +9 -0
+# netcat is as shy as Busybox and would not override existing files.
+ifeq ($(BR2_PACKAGE_BUSYBOX),y)
+NETCAT_DEPENDENCIES += busybox
+define NETCAT_RMOVE_NC_LINK
+	rm -f $(TARGET_DIR)/usr/bin/nc
+endef
+NETCAT_PRE_INSTALL_TARGET_HOOKS += NETCAT_RMOVE_NC_LINK
+endif
+
 $(eval $(autotools-package))

_______________________________________________
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Signature · 6 lines
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF
#4 lore raw

PATCH 1/1 netcat: add forced dependence on BusyBox

Arnout, All,

On 2018-03-31 15:03 +0200, Arnout Vandecappelle spake thusly:

Quoted 16 lines · Romain Naour
Quoted 15 lines

Hi Carlos,

Le 12/10/2017 ? 17:14, Carlos Santos a ?crit?:

Quoted 8 lines

It may be necessary if packages become built in parallel, leading to a race condition on the creation of the "nc" link. Moreover, netcat is as shy as BusyBox and would not override an existing file/link, so we must remove $(TARGET_DIR)/usr/bin/nc in advance.

Of course this still leaves a race conditon if other netcat competitors but we must assume thet the user is a grown-up person who knows what is doing.

It seems you are using a custom busybox config file because the netcat applet is disabled by default.

Quoted 8 lines
Quoted 5 lines

I'm agree, the dependency on busybox is missing but the TARGET_HOOKS doesn't seems necessary. I removed it and netcat package is able to override the busybox symlink.

/usr/bin/install -c netcat output/target/usr/bin/netcat

And anyway, in the context of PPS we will eventually have to reverse the
busybox dependencies, i.e. busybox will depend on netcat.

Actually, we can do that even before PPS...

Regards,
Yann E. MORIN.

Quoted 57 lines
Quoted 2 lines

Maybe we should check if other packages depending on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS have a dependency on busybox.

check-uniq-files should cover this.

Regards,
Arnout

Quoted 37 lines

Best regards,
Romain

Quoted 17 lines
---
 package/netcat/netcat.mk | 11 +++++++++++
 1 file changed, 11 insertions(+)
package/netcat/netcat.mk +2 -0
index eb7ddcac27..c032eea56d 100644
@@ -9,4 +9,15 @@ NETCAT_SITE = http://downloads.sourceforge.net/project/netcat/netcat/$(NETCAT_VE
 NETCAT_LICENSE = GPL-2.0+
 NETCAT_LICENSE_FILES = COPYING
 
+# Ensure Busybox gets built/installed before, so that this package
+# overrides Busybox nc. We must remove an existing file/link because

package/netcat/netcat.mk NETCAT_SITE = http://downloads.sourceforge.net/project/netcat/netcat/$(NETCAT_VE · line 23

Quoted 10 lines
package/netcat/netcat.mk +9 -0
+# netcat is as shy as Busybox and would not override existing files.
+ifeq ($(BR2_PACKAGE_BUSYBOX),y)
+NETCAT_DEPENDENCIES += busybox
+define NETCAT_RMOVE_NC_LINK
+	rm -f $(TARGET_DIR)/usr/bin/nc
+endef
+NETCAT_PRE_INSTALL_TARGET_HOOKS += NETCAT_RMOVE_NC_LINK
+endif
+
 $(eval $(autotools-package))

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Signature · 10 lines
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF
_______________________________________________
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Signature · 6 lines
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| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
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'------------------------------^-------^------------------^--------------------'
#5 lore raw

PATCH 1/1 netcat: add forced dependence on BusyBox

In reply to Romain Naour
Quoted 12 lines · Romain Naour

Hi Carlos,

Le 12/10/2017 ? 17:14, Carlos Santos a ?crit?:

Quoted 8 lines

It may be necessary if packages become built in parallel, leading to a race condition on the creation of the "nc" link. Moreover, netcat is as shy as BusyBox and would not override an existing file/link, so we must remove $(TARGET_DIR)/usr/bin/nc in advance.

Of course this still leaves a race conditon if other netcat competitors but we must assume thet the user is a grown-up person who knows what is doing.

Quoted 8 lines

It seems you are using a custom busybox config file because the netcat applet is disabled by default.

I'm agree, the dependency on busybox is missing but the TARGET_HOOKS doesn't seems necessary. I removed it and netcat package is able to override the busybox symlink.

/usr/bin/install -c netcat output/target/usr/bin/netcat

I've applied, after removing the unneeded removal of nc.

If it turns out to be needed after all, please submit a follow-up patch.

Regards,
Arnout

Quoted 3 lines

Maybe we should check if other packages depending on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS have a dependency on busybox.

[snip]

Signature · 6 lines
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF
#6 lore raw

PATCH 1/1 netcat: add forced dependence on BusyBox

Quoted 22 lines · Arnout Vandecappelle
Quoted 19 lines · Romain Naour

Hi Carlos,

Le 12/10/2017 ? 17:14, Carlos Santos a ?crit?:

Quoted 8 lines

It may be necessary if packages become built in parallel, leading to a race condition on the creation of the "nc" link. Moreover, netcat is as shy as BusyBox and would not override an existing file/link, so we must remove $(TARGET_DIR)/usr/bin/nc in advance.

Of course this still leaves a race conditon if other netcat competitors but we must assume thet the user is a grown-up person who knows what is doing.

It seems you are using a custom busybox config file because the netcat applet is disabled by default.

I'm agree, the dependency on busybox is missing but the TARGET_HOOKS doesn't seems necessary. I removed it and netcat package is able to override the busybox symlink.

Quoted 5 lines
Quoted 1 line

/usr/bin/install -c netcat output/target/usr/bin/netcat

I've applied, after removing the unneeded removal of nc.

If it turns out to be needed after all, please submit a follow-up patch.

OK, so it *was* needed, so I pushed a follow-up commit that does the removal.

I've done that unconditionally, though, the 'nc' could come from somewhere else
as well.

Regards,
Arnout

Signature · 6 lines
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF
#7 lore raw

PATCH v4 1/1 nmap: add option to build/install ncat

In reply to Carlos Santos

Hello,

Quoted 17 lines · Carlos Santos

Ncat is a much-improved reimplementation of the venerable Netcat and is compatible with uClibc and musl. It provides features not available in the ancient GNU netcat and its Busybox double like IPv6, proxies, and Unix sockets.

Tha nmap package now installs ncat if the BR2_PACKAGE_NMAP_NCAT option is selected. The other programs (nmap, ndiff, etc.) are chosen via the BR2_PACKAGE_NMAP_NMAP option.

We symlink 'nc' to ncat if neiter netcat nor netcat-openbsd is selected, even though ncat does not have the same interface as netcat-openbsd. However, since Fedora/RHEL install nmap-ncat as 'nc', it can be assumed that packages that depend on 'nc' know how to deal with this diversity. For example, the virt-manager package does that. Also user-supplied scripts can be assumed to do the right thing, since the user also selects whether nmap-ncat, netcat or netcat-openbsd is installed.

Quoted 1 line

We looked at this in further details with Arnout, and we still didn't like the special casing for the ncat-only case. In addition, it is weird to have suboptions for nmap and ncat, while the package also installs nping and ndiff.

So instead, I've added sub-options for nmap, ncat, ndiff and nping, and then I've played with make targets to only build/install what's needed. The nmap Makefile.in conveniently offers the following make targets:

nmap, build-ncat, build-nping, build-ndiff

to build the respective programs, and:

install-nmap, install-ncat, install-nping, install-ndiff

to install the respective programs.

I've used this solution, which makes the package a lot cleaner and easier to read I believe. See the final commit at
https://git.buildroot.org/buildroot/commit/?id=55ec9b4e40b08a11cb9c1662c427c8d58351924a.

Best regards,

Thomas

Signature · 3 lines
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com