From 62f3d8adbc0381223499ff2bef45b23e7dca401d Mon Sep 17 00:00:00 2001 From: Michal Privoznik Date: Thu, 27 Feb 2020 11:06:22 +0100 Subject: [PATCH] security: Introduce VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP flag Our decision whether to remember seclabel for a disk image depends on a few factors. If the image is readonly or shared or not the chain top the remembering is suppressed for the image. However, the virSecurityManagerSetImageLabel() is too low level to determine whether passed @src is chain top or not. Even though the function has the @parent argument it does not necessarily reflect the chain top - it only points to the top level image in the chain we want to relabel and not to the topmost image of the whole chain. And this can't be derived from the passed domain definition reliably neither - in some cases (like snapshots or block copy) the @src is added to the definition only after the operation succeeded. Therefore, introduce a flag which callers can use to help us with the decision. Signed-off-by: Michal Privoznik Reviewed-by: Peter Krempa --- src/security/security_dac.c | 15 ++++++++++----- src/security/security_manager.h | 4 ++++ src/security/security_selinux.c | 17 +++++++++++------ 3 files changed, 25 insertions(+), 11 deletions(-) diff --git a/src/security/security_dac.c b/src/security/security_dac.c index f412054d0e..9046b51004 100644 --- a/src/security/security_dac.c +++ b/src/security/security_dac.c @@ -889,14 +889,14 @@ static int virSecurityDACSetImageLabelInternal(virSecurityManagerPtr mgr, virDomainDefPtr def, virStorageSourcePtr src, - virStorageSourcePtr parent) + virStorageSourcePtr parent, + bool isChainTop) { virSecurityLabelDefPtr secdef; virSecurityDeviceLabelDefPtr disk_seclabel; virSecurityDeviceLabelDefPtr parent_seclabel = NULL; virSecurityDACDataPtr priv = virSecurityManagerGetPrivateData(mgr); bool remember; - bool is_toplevel = parent == src || parent->externalDataStore == src; uid_t user; gid_t group; @@ -954,7 +954,7 @@ virSecurityDACSetImageLabelInternal(virSecurityManagerPtr mgr, * but the top layer, or read only image, or disk explicitly * marked as shared. */ - remember = is_toplevel && !src->readonly && !src->shared; + remember = isChainTop && !src->readonly && !src->shared; return virSecurityDACSetOwnership(mgr, src, NULL, user, group, remember); } @@ -970,7 +970,9 @@ virSecurityDACSetImageLabelRelative(virSecurityManagerPtr mgr, virStorageSourcePtr n; for (n = src; virStorageSourceIsBacking(n); n = n->backingStore) { - if (virSecurityDACSetImageLabelInternal(mgr, def, n, parent) < 0) + const bool isChainTop = flags & VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP; + + if (virSecurityDACSetImageLabelInternal(mgr, def, n, parent, isChainTop) < 0) return -1; if (n->externalDataStore && @@ -983,6 +985,8 @@ virSecurityDACSetImageLabelRelative(virSecurityManagerPtr mgr, if (!(flags & VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN)) break; + + flags &= ~VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP; } return 0; @@ -2114,7 +2118,8 @@ virSecurityDACSetAllLabel(virSecurityManagerPtr mgr, if (virDomainDiskGetType(def->disks[i]) == VIR_STORAGE_TYPE_DIR) continue; if (virSecurityDACSetImageLabel(mgr, def, def->disks[i]->src, - VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN) < 0) + VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN | + VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP) < 0) return -1; } diff --git a/src/security/security_manager.h b/src/security/security_manager.h index b92ea5dc87..7699bcbc6f 100644 --- a/src/security/security_manager.h +++ b/src/security/security_manager.h @@ -151,6 +151,10 @@ virSecurityManagerPtr* virSecurityManagerGetNested(virSecurityManagerPtr mgr); typedef enum { VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN = 1 << 0, + /* The VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP should be set if the + * image passed to virSecurityManagerSetImageLabel() is the top parent of + * the whole backing chain. */ + VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP = 1 << 1, } virSecurityDomainImageLabelFlags; int virSecurityManagerSetImageLabel(virSecurityManagerPtr mgr, diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c index 2241a35e6e..e9aa8af877 100644 --- a/src/security/security_selinux.c +++ b/src/security/security_selinux.c @@ -1824,7 +1824,8 @@ static int virSecuritySELinuxSetImageLabelInternal(virSecurityManagerPtr mgr, virDomainDefPtr def, virStorageSourcePtr src, - virStorageSourcePtr parent) + virStorageSourcePtr parent, + bool isChainTop) { virSecuritySELinuxDataPtr data = virSecurityManagerGetPrivateData(mgr); virSecurityLabelDefPtr secdef; @@ -1832,7 +1833,6 @@ virSecuritySELinuxSetImageLabelInternal(virSecurityManagerPtr mgr, virSecurityDeviceLabelDefPtr parent_seclabel = NULL; char *use_label = NULL; bool remember; - bool is_toplevel = parent == src || parent->externalDataStore == src; g_autofree char *vfioGroupDev = NULL; const char *path = src->path; int ret; @@ -1856,7 +1856,7 @@ virSecuritySELinuxSetImageLabelInternal(virSecurityManagerPtr mgr, * but the top layer, or read only image, or disk explicitly * marked as shared. */ - remember = is_toplevel && !src->readonly && !src->shared; + remember = isChainTop && !src->readonly && !src->shared; disk_seclabel = virStorageSourceGetSecurityLabelDef(src, SECURITY_SELINUX_NAME); @@ -1873,7 +1873,7 @@ virSecuritySELinuxSetImageLabelInternal(virSecurityManagerPtr mgr, return 0; use_label = parent_seclabel->label; - } else if (is_toplevel) { + } else if (parent == src || parent->externalDataStore == src) { if (src->shared) { use_label = data->file_context; } else if (src->readonly) { @@ -1930,7 +1930,9 @@ virSecuritySELinuxSetImageLabelRelative(virSecurityManagerPtr mgr, virStorageSourcePtr n; for (n = src; virStorageSourceIsBacking(n); n = n->backingStore) { - if (virSecuritySELinuxSetImageLabelInternal(mgr, def, n, parent) < 0) + const bool isChainTop = flags & VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP; + + if (virSecuritySELinuxSetImageLabelInternal(mgr, def, n, parent, isChainTop) < 0) return -1; if (n->externalDataStore && @@ -1943,6 +1945,8 @@ virSecuritySELinuxSetImageLabelRelative(virSecurityManagerPtr mgr, if (!(flags & VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN)) break; + + flags &= ~VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP; } return 0; @@ -3146,7 +3150,8 @@ virSecuritySELinuxSetAllLabel(virSecurityManagerPtr mgr, continue; } if (virSecuritySELinuxSetImageLabel(mgr, def, def->disks[i]->src, - VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN) < 0) + VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN | + VIR_SECURITY_DOMAIN_IMAGE_PARENT_CHAIN_TOP) < 0) return -1; } /* XXX fixme process def->fss if relabel == true */