From: Zqiang <[email protected]> Selinux MCS generate a single category context and may be accessed by another machine.
link: https://gitlab.com/libvirt/libvirt/-/issues/153 Signed-off-by: Zqiang <[email protected]> --- ...y-fix-SELinux-label-generation-logic.patch | 54 +++++++++++++++++++ recipes-extended/libvirt/libvirt_7.2.0.bb | 1 + 2 files changed, 55 insertions(+) create mode 100644 recipes-extended/libvirt/libvirt/0001-security-fix-SELinux-label-generation-logic.patch diff --git a/recipes-extended/libvirt/libvirt/0001-security-fix-SELinux-label-generation-logic.patch b/recipes-extended/libvirt/libvirt/0001-security-fix-SELinux-label-generation-logic.patch new file mode 100644 index 00000000..e8952c36 --- /dev/null +++ b/recipes-extended/libvirt/libvirt/0001-security-fix-SELinux-label-generation-logic.patch @@ -0,0 +1,54 @@ +From 15073504dbb624d3f6c911e85557019d3620fdb2 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <[email protected]> +Date: Mon, 28 Jun 2021 13:09:04 +0100 +Subject: [PATCH] security: fix SELinux label generation logic +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +A process can access a file if the set of MCS categories +for the file is equal-to *or* a subset-of, the set of +MCS categories for the process. + +If there are two VMs: + + a) svirt_t:s0:c117 + b) svirt_t:s0:c117,c720 + +Then VM (b) is able to access files labelled for VM (a). + +IOW, we must discard case where the categories are equal +because that is a subset of many other valid category pairs. + +Fixes: https://gitlab.com/libvirt/libvirt/-/issues/153 +CVE-2021-3631 +Reviewed-by: Peter Krempa <[email protected]> +Signed-off-by: Daniel P. Berrangé <[email protected]> +--- + src/security/security_selinux.c | 10 +++++++++- + 1 file changed, 9 insertions(+), 1 deletion(-) + +diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c +index b50f4463cc..0c2cf1d1c7 100644 +--- a/src/security/security_selinux.c ++++ b/src/security/security_selinux.c +@@ -383,7 +383,15 @@ virSecuritySELinuxMCSFind(virSecurityManager *mgr, + VIR_DEBUG("Try cat %s:c%d,c%d", sens, c1 + catMin, c2 + catMin); + + if (c1 == c2) { +- mcs = g_strdup_printf("%s:c%d", sens, catMin + c1); ++ /* ++ * A process can access a file if the set of MCS categories ++ * for the file is equal-to *or* a subset-of, the set of ++ * MCS categories for the process. ++ * ++ * IOW, we must discard case where the categories are equal ++ * because that is a subset of other category pairs. ++ */ ++ continue; + } else { + if (c1 > c2) { + int t = c1; +-- +2.17.1 + diff --git a/recipes-extended/libvirt/libvirt_7.2.0.bb b/recipes-extended/libvirt/libvirt_7.2.0.bb index 9cf29511..b7f8383a 100644 --- a/recipes-extended/libvirt/libvirt_7.2.0.bb +++ b/recipes-extended/libvirt/libvirt_7.2.0.bb @@ -29,6 +29,7 @@ SRC_URI = "http://libvirt.org/sources/libvirt-${PV}.tar.xz;name=libvirt \ file://hook_support.py \ file://gnutls-helper.py \ file://0002-meson-Fix-compatibility-with-Meson-0.58.patch \ + file://0001-security-fix-SELinux-label-generation-logic.patch \ " SRC_URI[libvirt.md5sum] = "92044b629216e44adce63224970a54a3" -- 2.17.1
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