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common/config: don't hard-code SELinux context

PATCH In review Eric Biggers 2 participants 2 messages Mar 14, 2017 – Mar 15, 2017

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#0 lore raw

PATCH v2 1/1 common/config: don't hard-code SELinux context

From: Eric Biggers <[email protected]>

If SELinux is enabled, by default xfstests mounts its filesystems with "-o context=system_u:object_r:nfs_t:s0" so that no SELinux xattrs get created and interfere with tests. However, this particular context is not guaranteed to be available because the context names are a detail of the SELinux policy. The SELinux policy on Android systems, for example, does not have a context with this name.

To fix this without having to manually override SELINUX_MOUNT_OPTIONS, just grab the SELinux context of the root directory. This is arbitrary, but it should always provide a valid context. And if for some reason someone is actually running xfstests in a specific SELinux context that needs files labeled with a particular context, then they may still override SELINUX_MOUNT_OPTIONS.

---
 common/config | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
common/config +10 -3
index 0c7335ad..5bcf114d 100644
@@ -260,11 +260,18 @@ case "$HOSTOS" in
 esac
 
 # SELinux adds extra xattrs which can mess up our expected output.
-# So, mount with a context, and they won't be created
-# # nfs_t is a "liberal" context so we can use it.
+# So, mount with a context, and they won't be created.
+#
+# Since the context= option only accepts contexts defined in the SELinux
+# policy, and different systems may have different policies with
+# different context names, use the context of an existing directory.
+# Assume that any valid context is fine, since xfstests should really
+# only be run from an "unconfined" process, or with SELinux in permissive
+# mode.  But if not, just specify your own SELINUX_MOUNT_OPTIONS.
 if [ -x /usr/sbin/selinuxenabled ] && /usr/sbin/selinuxenabled; then
-	: ${SELINUX_MOUNT_OPTIONS:="-o context=system_u:object_r:nfs_t:s0"}
+	: ${SELINUX_MOUNT_OPTIONS:="-o context=$(stat -c %C /)"}
 	export SELINUX_MOUNT_OPTIONS
+
 fi
 
 # check if mkfs.xfs supports v5 xfs
Signature · 1 line
2.12.0.367.g23dc2f6d3c-goog
#1 lore raw
Quoted 34 lines · Eric Biggers

From: Eric Biggers <[email protected]>

If SELinux is enabled, by default xfstests mounts its filesystems with "-o context=system_u:object_r:nfs_t:s0" so that no SELinux xattrs get created and interfere with tests. However, this particular context is not guaranteed to be available because the context names are a detail of the SELinux policy. The SELinux policy on Android systems, for example, does not have a context with this name.

To fix this without having to manually override SELINUX_MOUNT_OPTIONS, just grab the SELinux context of the root directory. This is arbitrary, but it should always provide a valid context. And if for some reason someone is actually running xfstests in a specific SELinux context that needs files labeled with a particular context, then they may still override SELINUX_MOUNT_OPTIONS.

---
 common/config | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
common/config +3 -2
index 0c7335ad..5bcf114d 100644
@@ -260,11 +260,18 @@ case "$HOSTOS" in
 esac
 
 # SELinux adds extra xattrs which can mess up our expected output.
-# So, mount with a context, and they won't be created
-# # nfs_t is a "liberal" context so we can use it.
+# So, mount with a context, and they won't be created.
+#
+# Since the context= option only accepts contexts defined in the SELinux

common/config case "$HOSTOS" in · line 274

Quoted 10 lines
common/config +7 -1
+# policy, and different systems may have different policies with
+# different context names, use the context of an existing directory.
+# Assume that any valid context is fine, since xfstests should really
+# only be run from an "unconfined" process, or with SELinux in permissive
+# mode.  But if not, just specify your own SELINUX_MOUNT_OPTIONS.
 if [ -x /usr/sbin/selinuxenabled ] && /usr/sbin/selinuxenabled; then
-	: ${SELINUX_MOUNT_OPTIONS:="-o context=system_u:object_r:nfs_t:s0"}
+	: ${SELINUX_MOUNT_OPTIONS:="-o context=$(stat -c %C /)"}
 	export SELINUX_MOUNT_OPTIONS
+

I removed this extra empty line and committed patch to stage tree.

Thanks,
Eryu

Quoted 10 lines
common/config +0 -0
 fi
 
 # check if mkfs.xfs supports v5 xfs
Signature · 6 lines
2.12.0.367.g23dc2f6d3c-goog

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