[source] basefiles: allow suid coredumps

[LEDE Commits]

dedeckeh pushed a commit to source.git, branch master:
https://git.lede-project.org/7765e442d04e4c19690f81084a9726776aea8b76

commit 7765e442d04e4c19690f81084a9726776aea8b76
Author: Kevin Darbyshire-Bryant <ldir at darbyshire-bryant.me.uk>
AuthorDate: Mon Sep 4 13:13:24 2017 +0100

    basefiles: allow suid coredumps
    
    Set sysctl fs.suid_dumpable = 2
    
    This allows suid processes to dump core according to kernel.core_pattern
    setting.  LEDE typically uses suid to drop root priviledge rather than
    gain it but without this setting any suid process would be unable to
    produce coredumps (e.g. dnsmasq)
    
    Processes still need to set a non zero core file process limit ('ulimit
    -c unlimited' or if procd used 'procd_set_param limits
    core="unlimited"') in order to produce a core.  This setting removes an
    obscure stumbling block along the way.
    
    >From https://www.kernel.org/doc/Documentation/sysctl/fs.txt
    
    suid_dumpable:
    
    This value can be used to query and set the core dump mode for setuid
    or otherwise protected/tainted binaries. The modes are
    
    0 - (default) - traditional behaviour. Any process which has changed
    	privilege levels or is execute only will not be dumped.
    1 - (debug) - all processes dump core when possible. The core dump is
    	owned by the current user and no security is applied. This is
    	intended for system debugging situations only. Ptrace is unchecked.
    	This is insecure as it allows regular users to examine the memory
    	contents of privileged processes.
    2 - (suidsafe) - any binary which normally would not be dumped is dumped
    	anyway, but only if the "core_pattern" kernel sysctl is set to
    	either a pipe handler or a fully qualified path. (For more details
    	on this limitation, see CVE-2006-2451.) This mode is appropriate
    	when administrators are attempting to debug problems in a normal
    	environment, and either have a core dump pipe handler that knows
    	to treat privileged core dumps with care, or specific directory
    	defined for catching core dumps. If a core dump happens without
    	a pipe handler or fully qualifid path, a message will be emitted
    	to syslog warning about the lack of a correct setting.
    
    Signed-off-by: Kevin Darbyshire-Bryant <ldir at darbyshire-bryant.me.uk>
    Signed-off-by: Hans Dedecker <dedeckeh at gmail.com> [PKG_RELEASE increase]
---
 package/base-files/Makefile              | 2 +-
 package/base-files/files/etc/sysctl.conf | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/package/base-files/Makefile b/package/base-files/Makefile
index d92069e..d8ee46e 100644
--- a/package/base-files/Makefile
+++ b/package/base-files/Makefile
@@ -11,7 +11,7 @@ include $(INCLUDE_DIR)/kernel.mk
 include $(INCLUDE_DIR)/version.mk
 
 PKG_NAME:=base-files
-PKG_RELEASE:=174
+PKG_RELEASE:=175
 PKG_FLAGS:=nonshared
 
 PKG_FILE_DEPENDS:=$(PLATFORM_DIR)/ $(GENERIC_PLATFORM_DIR)/base-files/
diff --git a/package/base-files/files/etc/sysctl.conf b/package/base-files/files/etc/sysctl.conf
index 91a3ac9..ddc7a9b 100644
--- a/package/base-files/files/etc/sysctl.conf
+++ b/package/base-files/files/etc/sysctl.conf
@@ -1,5 +1,6 @@
 kernel.panic=3
 kernel.core_pattern=/tmp/%e.%t.%p.%s.core
+fs.suid_dumpable=2
 
 net.ipv4.conf.default.arp_ignore=1
 net.ipv4.conf.all.arp_ignore=1