[libvirt] [PATCH v1 1/5] qemu: Expose qemuOpenFile and qemuOpenFileAs
Michal Privoznik
mprivozn at redhat.com
Thu Nov 27 13:55:45 UTC 2014
This is a pure code movement. Both of the APIs are going to be
needed later in several areas of qemu driver code.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
src/qemu/qemu_domain.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++
src/qemu/qemu_domain.h | 10 ++++
src/qemu/qemu_driver.c | 156 -------------------------------------------------
3 files changed, 157 insertions(+), 156 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 6513c78..e500fb3 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2810,3 +2810,150 @@ qemuDomainAgentAvailable(qemuDomainObjPrivatePtr priv,
}
return true;
}
+
+/* Internal function to properly create or open existing files, with
+ * ownership affected by qemu driver setup and domain DAC label. */
+int
+qemuOpenFile(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ const char *path, int oflags,
+ bool *needUnlink, bool *bypassSecurityDriver)
+{
+ int ret = -1;
+ virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+ uid_t user = cfg->user;
+ gid_t group = cfg->group;
+ bool dynamicOwnership = cfg->dynamicOwnership;
+ virSecurityLabelDefPtr seclabel;
+
+ virObjectUnref(cfg);
+
+ /* TODO: Take imagelabel into account? */
+ if (vm &&
+ (seclabel = virDomainDefGetSecurityLabelDef(vm->def, "dac")) != NULL &&
+ seclabel->label != NULL &&
+ (virParseOwnershipIds(seclabel->label, &user, &group) < 0))
+ goto cleanup;
+
+ ret = qemuOpenFileAs(user, group, dynamicOwnership,
+ path, oflags, needUnlink, bypassSecurityDriver);
+
+ cleanup:
+ return ret;
+}
+
+
+int
+qemuOpenFileAs(uid_t fallback_uid, gid_t fallback_gid,
+ bool dynamicOwnership,
+ const char *path, int oflags,
+ bool *needUnlink, bool *bypassSecurityDriver)
+{
+ struct stat sb;
+ bool is_reg = true;
+ bool need_unlink = false;
+ bool bypass_security = false;
+ unsigned int vfoflags = 0;
+ int fd = -1;
+ int path_shared = virFileIsSharedFS(path);
+ uid_t uid = geteuid();
+ gid_t gid = getegid();
+
+ /* path might be a pre-existing block dev, in which case
+ * we need to skip the create step, and also avoid unlink
+ * in the failure case */
+ if (oflags & O_CREAT) {
+ need_unlink = true;
+
+ /* Don't force chown on network-shared FS
+ * as it is likely to fail. */
+ if (path_shared <= 0 || dynamicOwnership)
+ vfoflags |= VIR_FILE_OPEN_FORCE_OWNER;
+
+ if (stat(path, &sb) == 0) {
+ is_reg = !!S_ISREG(sb.st_mode);
+ /* If the path is regular file which exists
+ * already and dynamic_ownership is off, we don't
+ * want to change it's ownership, just open it as-is */
+ if (is_reg && !dynamicOwnership) {
+ uid = sb.st_uid;
+ gid = sb.st_gid;
+ }
+ }
+ }
+
+ /* First try creating the file as root */
+ if (!is_reg) {
+ if ((fd = open(path, oflags & ~O_CREAT)) < 0) {
+ fd = -errno;
+ goto error;
+ }
+ } else {
+ if ((fd = virFileOpenAs(path, oflags, S_IRUSR | S_IWUSR, uid, gid,
+ vfoflags | VIR_FILE_OPEN_NOFORK)) < 0) {
+ /* If we failed as root, and the error was permission-denied
+ (EACCES or EPERM), assume it's on a network-connected share
+ where root access is restricted (eg, root-squashed NFS). If the
+ qemu user is non-root, just set a flag to
+ bypass security driver shenanigans, and retry the operation
+ after doing setuid to qemu user */
+ if ((fd != -EACCES && fd != -EPERM) || fallback_uid == geteuid())
+ goto error;
+
+ /* On Linux we can also verify the FS-type of the directory. */
+ switch (path_shared) {
+ case 1:
+ /* it was on a network share, so we'll continue
+ * as outlined above
+ */
+ break;
+
+ case -1:
+ virReportSystemError(-fd, oflags & O_CREAT
+ ? _("Failed to create file "
+ "'%s': couldn't determine fs type")
+ : _("Failed to open file "
+ "'%s': couldn't determine fs type"),
+ path);
+ goto cleanup;
+
+ case 0:
+ default:
+ /* local file - log the error returned by virFileOpenAs */
+ goto error;
+ }
+
+ /* Retry creating the file as qemu user */
+
+ if ((fd = virFileOpenAs(path, oflags,
+ S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP,
+ fallback_uid, fallback_gid,
+ vfoflags | VIR_FILE_OPEN_FORK)) < 0) {
+ virReportSystemError(-fd, oflags & O_CREAT
+ ? _("Error from child process creating '%s'")
+ : _("Error from child process opening '%s'"),
+ path);
+ goto cleanup;
+ }
+
+ /* Since we had to setuid to create the file, and the fstype
+ is NFS, we assume it's a root-squashing NFS share, and that
+ the security driver stuff would have failed anyway */
+
+ bypass_security = true;
+ }
+ }
+ cleanup:
+ if (needUnlink)
+ *needUnlink = need_unlink;
+ if (bypassSecurityDriver)
+ *bypassSecurityDriver = bypass_security;
+ return fd;
+
+ error:
+ virReportSystemError(-fd, oflags & O_CREAT
+ ? _("Failed to create file '%s'")
+ : _("Failed to open file '%s'"),
+ path);
+ goto cleanup;
+}
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index e4ea4ce..5f36892 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -414,4 +414,14 @@ int qemuDomainJobInfoToParams(qemuDomainJobInfoPtr jobInfo,
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2)
ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4);
+int qemuOpenFile(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ const char *path, int oflags,
+ bool *needUnlink, bool *bypassSecurityDriver);
+
+int qemuOpenFileAs(uid_t fallback_uid, gid_t fallback_gid,
+ bool dynamicOwnership,
+ const char *path, int oflags,
+ bool *needUnlink, bool *bypassSecurityDriver);
+
#endif /* __QEMU_DOMAIN_H__ */
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 07da3e3..561fa6c 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -160,16 +160,6 @@ static int qemuDomainGetMaxVcpus(virDomainPtr dom);
static int qemuDomainManagedSaveLoad(virDomainObjPtr vm,
void *opaque);
-static int qemuOpenFile(virQEMUDriverPtr driver,
- virDomainObjPtr vm,
- const char *path, int oflags,
- bool *needUnlink, bool *bypassSecurityDriver);
-
-static int qemuOpenFileAs(uid_t fallback_uid, gid_t fallback_gid,
- bool dynamicOwnership,
- const char *path, int oflags,
- bool *needUnlink, bool *bypassSecurityDriver);
-
virQEMUDriverPtr qemu_driver = NULL;
@@ -2881,152 +2871,6 @@ qemuCompressGetCommand(virQEMUSaveFormat compression)
return ret;
}
-/* Internal function to properly create or open existing files, with
- * ownership affected by qemu driver setup and domain DAC label. */
-static int
-qemuOpenFile(virQEMUDriverPtr driver,
- virDomainObjPtr vm,
- const char *path, int oflags,
- bool *needUnlink, bool *bypassSecurityDriver)
-{
- int ret = -1;
- virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
- uid_t user = cfg->user;
- gid_t group = cfg->group;
- bool dynamicOwnership = cfg->dynamicOwnership;
- virSecurityLabelDefPtr seclabel;
-
- virObjectUnref(cfg);
-
- /* TODO: Take imagelabel into account? */
- if (vm &&
- (seclabel = virDomainDefGetSecurityLabelDef(vm->def, "dac")) != NULL &&
- seclabel->label != NULL &&
- (virParseOwnershipIds(seclabel->label, &user, &group) < 0))
- goto cleanup;
-
- ret = qemuOpenFileAs(user, group, dynamicOwnership,
- path, oflags, needUnlink, bypassSecurityDriver);
-
- cleanup:
- return ret;
-}
-
-static int
-qemuOpenFileAs(uid_t fallback_uid, gid_t fallback_gid,
- bool dynamicOwnership,
- const char *path, int oflags,
- bool *needUnlink, bool *bypassSecurityDriver)
-{
- struct stat sb;
- bool is_reg = true;
- bool need_unlink = false;
- bool bypass_security = false;
- unsigned int vfoflags = 0;
- int fd = -1;
- int path_shared = virFileIsSharedFS(path);
- uid_t uid = geteuid();
- gid_t gid = getegid();
-
- /* path might be a pre-existing block dev, in which case
- * we need to skip the create step, and also avoid unlink
- * in the failure case */
- if (oflags & O_CREAT) {
- need_unlink = true;
-
- /* Don't force chown on network-shared FS
- * as it is likely to fail. */
- if (path_shared <= 0 || dynamicOwnership)
- vfoflags |= VIR_FILE_OPEN_FORCE_OWNER;
-
- if (stat(path, &sb) == 0) {
- is_reg = !!S_ISREG(sb.st_mode);
- /* If the path is regular file which exists
- * already and dynamic_ownership is off, we don't
- * want to change it's ownership, just open it as-is */
- if (is_reg && !dynamicOwnership) {
- uid = sb.st_uid;
- gid = sb.st_gid;
- }
- }
- }
-
- /* First try creating the file as root */
- if (!is_reg) {
- if ((fd = open(path, oflags & ~O_CREAT)) < 0) {
- fd = -errno;
- goto error;
- }
- } else {
- if ((fd = virFileOpenAs(path, oflags, S_IRUSR | S_IWUSR, uid, gid,
- vfoflags | VIR_FILE_OPEN_NOFORK)) < 0) {
- /* If we failed as root, and the error was permission-denied
- (EACCES or EPERM), assume it's on a network-connected share
- where root access is restricted (eg, root-squashed NFS). If the
- qemu user is non-root, just set a flag to
- bypass security driver shenanigans, and retry the operation
- after doing setuid to qemu user */
- if ((fd != -EACCES && fd != -EPERM) || fallback_uid == geteuid())
- goto error;
-
- /* On Linux we can also verify the FS-type of the directory. */
- switch (path_shared) {
- case 1:
- /* it was on a network share, so we'll continue
- * as outlined above
- */
- break;
-
- case -1:
- virReportSystemError(-fd, oflags & O_CREAT
- ? _("Failed to create file "
- "'%s': couldn't determine fs type")
- : _("Failed to open file "
- "'%s': couldn't determine fs type"),
- path);
- goto cleanup;
-
- case 0:
- default:
- /* local file - log the error returned by virFileOpenAs */
- goto error;
- }
-
- /* Retry creating the file as qemu user */
-
- if ((fd = virFileOpenAs(path, oflags,
- S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP,
- fallback_uid, fallback_gid,
- vfoflags | VIR_FILE_OPEN_FORK)) < 0) {
- virReportSystemError(-fd, oflags & O_CREAT
- ? _("Error from child process creating '%s'")
- : _("Error from child process opening '%s'"),
- path);
- goto cleanup;
- }
-
- /* Since we had to setuid to create the file, and the fstype
- is NFS, we assume it's a root-squashing NFS share, and that
- the security driver stuff would have failed anyway */
-
- bypass_security = true;
- }
- }
- cleanup:
- if (needUnlink)
- *needUnlink = need_unlink;
- if (bypassSecurityDriver)
- *bypassSecurityDriver = bypass_security;
- return fd;
-
- error:
- virReportSystemError(-fd, oflags & O_CREAT
- ? _("Failed to create file '%s'")
- : _("Failed to open file '%s'"),
- path);
- goto cleanup;
-}
-
/* Helper function to execute a migration to file with a correct save header
* the caller needs to make sure that the processors are stopped and do all other
* actions besides saving memory */
--
2.0.4
More information about the libvir-list
mailing list