[Re: [yocto] [meta-security][PATCH] libcap-ng: port CVE-2014-3215 patch] On 14.11.29 (Sat 20:51) akuster808 wrote:
> Joe, > > I went a head and updated to 7.4 which included the security fix. > Thanks for the reminder. Yeah, that's on my to-do list for meta-selinux, too. That's the right course of action on this one. :-) -J. > > - Armin > > On 11/27/2014 10:49 AM, Joe MacDonald wrote: > >Importing the patch from meta-selinux, which itself was a backport from > >the upstream source tree. > > > >Signed-off-by: Joe MacDonald <[email protected]> > >--- > > > >I mentioned a while back that I had at least one patch in meta-selinux that > >may > >apply to meta-security as well. I don't know if you guys are interested in > >this > >or not since the primary tool to demonstrate the exploit is seunshare, but > >it is > >a problem in libcap-ng itself and it is exploitable outside of the selinux > >framework. > > > >-J. > > > > .../libcap-ng/libcap-ng/CVE-2014-3215.patch | 91 > > ++++++++++++++++++++++ > > recipes-security/libcap-ng/libcap-ng_0.7.3.bb | 4 +- > > 2 files changed, 94 insertions(+), 1 deletion(-) > > create mode 100644 recipes-security/libcap-ng/libcap-ng/CVE-2014-3215.patch > > > >diff --git a/recipes-security/libcap-ng/libcap-ng/CVE-2014-3215.patch > >b/recipes-security/libcap-ng/libcap-ng/CVE-2014-3215.patch > >new file mode 100644 > >index 0000000..e9164d4 > >--- /dev/null > >+++ b/recipes-security/libcap-ng/libcap-ng/CVE-2014-3215.patch > >@@ -0,0 +1,91 @@ > >+libcap-ng: local privilege escalation due to capng_lock > >+ > >+Following the discussion here: > >+ > >+ http://openwall.com/lists/oss-security/2014/04/29/7 > >+ > >+This is known to impact SELinux tools, however the issue could be exploited > >by > >+any application using the relevant functions in libcap-ng provided it is > >suid > >+root. > >+ > >+Upstream-Status: Backport > >+ > >+Signed-off-by: Joe MacDonald <[email protected]> > >+ > >+diff --git a/docs/capng_lock.3 b/docs/capng_lock.3 > >+index 7683119..a070c1e 100644 > >+--- a/docs/capng_lock.3 > >++++ b/docs/capng_lock.3 > >+@@ -8,12 +8,13 @@ int capng_lock(void); > >+ > >+ .SH "DESCRIPTION" > >+ > >+-capng_lock will take steps to prevent children of the current process to > >regain full privileges if the uid is 0. This should be called while > >possessing the CAP_SETPCAP capability in the kernel. This function will do > >the following if permitted by the kernel: Set the NOROOT option on for > >PR_SET_SECUREBITS, set the NOROOT_LOCKED option to on for PR_SET_SECUREBITS, > >set the PR_NO_SETUID_FIXUP option on for PR_SET_SECUREBITS, and set the > >PR_NO_SETUID_FIXUP_LOCKED option on for PR_SET_SECUREBITS. > >++capng_lock will take steps to prevent children of the current process from > >gaining privileges by executing setuid programs. This should be called > >while possessing the CAP_SETPCAP capability in the kernel. > >+ > >++This function will do the following if permitted by the kernel: If the > >kernel supports PR_SET_NO_NEW_PRIVS, it will use it. Otherwise it will set > >the NOROOT option on for PR_SET_SECUREBITS, set the NOROOT_LOCKED option to > >on for PR_SET_SECUREBITS, set the PR_NO_SETUID_FIXUP option on for > >PR_SET_SECUREBITS, and set the PR_NO_SETUID_FIXUP_LOCKED option on for > >PR_SET_SECUREBITS. If both fail, it will return an error. > >+ > >+ .SH "RETURN VALUE" > >+ > >+-This returns 0 on success and a negative number on failure. -1 means a > >failure setting any of the PR_SET_SECUREBITS options. > >++This returns 0 on success and a negative number on failure. -1 means a > >failure to use PR_SET_NO_NEW_PRIVS and a failure setting any of the > >PR_SET_SECUREBITS options. > >+ > >+ .SH "SEE ALSO" > >+ > >+diff --git a/src/cap-ng.c b/src/cap-ng.c > >+index bd105ba..422f2bc 100644 > >+--- a/src/cap-ng.c > >++++ b/src/cap-ng.c > >+@@ -45,6 +45,7 @@ > >+ * 2.6.24 kernel XATTR_NAME_CAPS > >+ * 2.6.25 kernel PR_CAPBSET_DROP, CAPABILITY_VERSION_2 > >+ * 2.6.26 kernel PR_SET_SECUREBITS, SECURE_*_LOCKED, VERSION_3 > >++ * 3.5 kernel PR_SET_NO_NEW_PRIVS > >+ */ > >+ > >+ /* External syscall prototypes */ > >+@@ -122,6 +123,14 @@ extern int capget(cap_user_header_t header, const > >cap_user_data_t data); > >+ #define SECURE_NO_SETUID_FIXUP_LOCKED 3 /* make bit-2 immutable */ > >+ #endif > >+ > >++/* prctl values that we use */ > >++#ifndef PR_SET_SECUREBITS > >++#define PR_SET_SECUREBITS 28 > >++#endif > >++#ifndef PR_SET_NO_NEW_PRIVS > >++#define PR_SET_NO_NEW_PRIVS 38 > >++#endif > >++ > >+ // States: new, allocated, initted, updated, applied > >+ typedef enum { CAPNG_NEW, CAPNG_ERROR, CAPNG_ALLOCATED, CAPNG_INIT, > >+ CAPNG_UPDATED, CAPNG_APPLIED } capng_states_t; > >+@@ -663,15 +672,22 @@ int capng_change_id(int uid, int gid, capng_flags_t > >flag) > >+ > >+ int capng_lock(void) > >+ { > >+-#ifdef PR_SET_SECUREBITS > >+- int rc = prctl(PR_SET_SECUREBITS, > >+- 1 << SECURE_NOROOT | > >+- 1 << SECURE_NOROOT_LOCKED | > >+- 1 << SECURE_NO_SETUID_FIXUP | > >+- 1 << SECURE_NO_SETUID_FIXUP_LOCKED, 0, 0, 0); > >++ int rc; > >++ > >++ // On Linux 3.5 and up, we can directly prevent ourselves and > >++ // our descendents from gaining privileges. > >++ if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == 0) > >++ return 0; > >++ > >++ // This kernel is too old or otherwise doesn't support > >++ // PR_SET_NO_NEW_PRIVS. Fall back to using securebits. > >++ rc = prctl(PR_SET_SECUREBITS, > >++ 1 << SECURE_NOROOT | > >++ 1 << SECURE_NOROOT_LOCKED | > >++ 1 << SECURE_NO_SETUID_FIXUP | > >++ 1 << SECURE_NO_SETUID_FIXUP_LOCKED, 0, 0, 0); > >+ if (rc) > >+ return -1; > >+-#endif > >+ > >+ return 0; > >+ } > >diff --git a/recipes-security/libcap-ng/libcap-ng_0.7.3.bb > >b/recipes-security/libcap-ng/libcap-ng_0.7.3.bb > >index 3f225ba..1acf554 100644 > >--- a/recipes-security/libcap-ng/libcap-ng_0.7.3.bb > >+++ b/recipes-security/libcap-ng/libcap-ng_0.7.3.bb > >@@ -8,7 +8,9 @@ LIC_FILES_CHKSUM = > >"file://COPYING;md5=94d55d512a9ba36caa9b7df079bae19f \ > > file://COPYING.LIB;md5=e3eda01d9815f8d24aae2dbd89b68b06" > > > > SRC_URI = > > "http://people.redhat.com/sgrubb/libcap-ng/libcap-ng-${PV}.tar.gz \ > >- file://python.patch" > >+ file://python.patch \ > >+ file://CVE-2014-3215.patch \ > >+ " > > > > inherit lib_package autotools pythonnative > > > > -- -Joe MacDonald. :wq
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