Re: [libvirt] [PATCH 1/2] virt-aa-helper: add rules for shmem devices

On Tue, 22 Oct 2019, Christian Ehrhardt wrote: > Shared memory devices need qemu to be able to access certain paths > either for the shared memory directly (mostly ivshmem-plain) or for a > socket (mostly ivshmem-doorbell). > > Add logic to virt-aa-helper to render those apparmor rules based > on the domain configuration. > > https://bugzilla.redhat.com/show_bug.cgi?id=1761645 > > Signed-off-by: Christian Ehrhardt <christian.ehrhardt(a)canonical.com&gt; > --- > src/security/virt-aa-helper.c | 35 +++++++++++++++++++++++++++++++++++ > 1 file changed, 35 insertions(+) > > diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c > index 7d7262ca39..8c261f0010 100644 > --- a/src/security/virt-aa-helper.c > +++ b/src/security/virt-aa-helper.c > @@ -958,6 +958,7 @@ get_files(vahControl * ctl) > int rc = -1; > size_t i; > char *uuid; > + char *mem_path = NULL; > char uuidstr[VIR_UUID_STRING_BUFLEN]; > bool needsVfio = false, needsvhost = false, needsgl = false; > > @@ -1224,6 +1225,39 @@ get_files(vahControl * ctl) > } > } > > + for (i = 0; i < ctl->def->nshmems; i++) { > + if (ctl->def->shmems[i]) { > + virDomainShmemDef *shmem = ctl->def->shmems[i]; > + /* server path can be on any type and overwrites defaults */ > + if (shmem->server.enabled && > + shmem->server.chr.data.nix.path) { > + if (vah_add_file(&buf, shmem->server.chr.data.nix.path, > + "rw") != 0) > + goto cleanup; I'll let others comment on the code changes, but this apparmor rule looks ok. > + } else { That said, I wonder about the logic here since up above we have: if (shmem->server.enabled && shmem->server.chr.data.nix.path) but here we just have 'else'. What happens if server.enabled is false and server.chr.data.nix.path is set or vice versa? Does this 'else' clause correctly handle those scenarios?

> + switch (shmem->model) { > + case VIR_DOMAIN_SHMEM_MODEL_IVSHMEM_PLAIN: > + /* until exposed, recreate qemuBuildShmemBackendMemProps */ > + if (virAsprintf(&mem_path, "/dev/shm/%s", shmem->name) < 0) > + goto cleanup; > + break; > + case VIR_DOMAIN_SHMEM_MODEL_IVSHMEM_DOORBELL: > + case VIR_DOMAIN_SHMEM_MODEL_IVSHMEM: > + /* until exposed, recreate qemuDomainPrepareShmemChardev */ > + if (virAsprintf(&mem_path, "/var/lib/libvirt/shmem-%s-sock", > + shmem->name) < 0) > + goto cleanup; > + break; > + } > + if (mem_path != NULL) { > + if (vah_add_file(&buf, mem_path, "rw") != 0) > + goto cleanup; > + } > + } > + } > + } > + -- Jamie Strandboge | http://www.canonical.com