6:13 a.m.
v2 of:
https://listman.redhat.com/archives/libvir-list/2021-September/msg00553.html
diff to v1:
- Reworded commit message in 2/2.
Michal Prívozník (2):
selinux: Swap two blocks handling setfilecon_raw() failure
selinux: Don't ignore ENOENT in Permissive mode
src/security/security_selinux.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)
--
2.32.0
6:13 a.m.
New subject: [PATCH v2 1/2] selinux: Swap two blocks handling setfilecon_raw() failure
In virSecuritySELinuxSetFileconImpl() we have code that handles
setfilecon_raw() failure. The code consists of two blocks: one
for dealing with shared filesystem like NFS (errno is ENOTSUP or
EROFS) and the other block that's dealing with EPERM for
privileged daemon. Well, the order of these two blocks is a bit
confusing because the comment above them mentions the NFS case
but EPERM block follows. Swap these two blocks to make it less
confusing.
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/security/security_selinux.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index 622a8f4c02..39c10cbe8f 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -1264,22 +1264,9 @@ virSecuritySELinuxSetFileconImpl(const char *path,
* boolean tunables to allow it ...
*/
VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
- if (setfilecon_errno != EOPNOTSUPP && setfilecon_errno != ENOTSUP
&&
- setfilecon_errno != EROFS) {
+ if (setfilecon_errno == EOPNOTSUPP || setfilecon_errno == ENOTSUP ||
+ setfilecon_errno == EROFS) {
VIR_WARNINGS_RESET
- /* However, don't claim error if SELinux is in Enforcing mode and
- * we are running as unprivileged user and we really did see EPERM.
- * Otherwise we want to return error if SELinux is Enforcing. */
- if (security_getenforce() == 1 &&
- (setfilecon_errno != EPERM || privileged)) {
- virReportSystemError(setfilecon_errno,
- _("unable to set security context '%s'
on '%s'"),
- tcon, path);
- return -1;
- }
- VIR_WARN("unable to set security context '%s' on '%s'
(errno %d)",
- tcon, path, setfilecon_errno);
- } else {
const char *msg;
if (virFileIsSharedFSType(path, VIR_FILE_SHFS_NFS) == 1 &&
security_get_boolean_active("virt_use_nfs") != 1) {
@@ -1293,6 +1280,19 @@ virSecuritySELinuxSetFileconImpl(const char *path,
VIR_INFO("Setting security context '%s' on '%s' not
supported",
tcon, path);
}
+ } else {
+ /* However, don't claim error if SELinux is in Enforcing mode and
+ * we are running as unprivileged user and we really did see EPERM.
+ * Otherwise we want to return error if SELinux is Enforcing. */
+ if (security_getenforce() == 1 &&
+ (setfilecon_errno != EPERM || privileged)) {
+ virReportSystemError(setfilecon_errno,
+ _("unable to set security context '%s'
on '%s'"),
+ tcon, path);
+ return -1;
+ }
+ VIR_WARN("unable to set security context '%s' on '%s'
(errno %d)",
+ tcon, path, setfilecon_errno);
}
return 1;
--
2.32.0
6:13 a.m.
New subject: [PATCH v2 2/2] selinux: Don't ignore ENOENT in Permissive mode
In selinux driver there's virSecuritySELinuxSetFileconImpl()
which is responsible for actual setting of SELinux label on given
file and handling possible failures. In fhe failure handling code
we decide whether failure is fatal or not. But there is a bug:
depending on SELinux mode (Permissive vs. Enforcing) the ENOENT
is either ignored or considered fatal. This not correct - ENOENT
must always be fatal for couple of reasons:
- In virSecurityStackTransactionCommit() the seclabels are set
for individual secdrivers (e.g. SELinux first and then DAC),
but if one secdriver succeeds and another one fails, then no
rollback is performed for the successful one leaking remembered
labels.
- QEMU would fail opening the file anyways (if neither of
secdrivers reported error and thus cancelled domain startup)
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2004850
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/security/security_selinux.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index 39c10cbe8f..a3b5fa7546 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -1283,9 +1283,11 @@ virSecuritySELinuxSetFileconImpl(const char *path,
} else {
/* However, don't claim error if SELinux is in Enforcing mode and
* we are running as unprivileged user and we really did see EPERM.
- * Otherwise we want to return error if SELinux is Enforcing. */
- if (security_getenforce() == 1 &&
- (setfilecon_errno != EPERM || privileged)) {
+ * Otherwise we want to return error if SELinux is Enforcing, or we
+ * saw EPERM regardless of SELinux mode. */
+ if (setfilecon_errno == ENOENT ||
+ (security_getenforce() == 1 &&
+ (setfilecon_errno != EPERM || privileged))) {
virReportSystemError(setfilecon_errno,
_("unable to set security context '%s'
on '%s'"),
tcon, path);
--
2.32.0
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Michal Privoznik