On 01/28/2014 12:12 PM, Felix Geyer wrote:
On 28.01.2014 15:04, Jamie Strandboge wrote:
> On 01/26/2014 03:47 PM, Felix Geyer wrote:
>> Make virt-aa-helper create rules to allow VMs access to filesystem
>> mounts from the host.
>
> Note that virt-aa-helper access to various parts of the filesystem is generally
> ok. However, can you be more specific about the problem you're trying to solve?
> Eg, is there a bug number?
virt-aa-helper doesn't create the appropriate rules to allow qemu access to
shared filesystem mounts:
http://libvirt.org/formatdomain.html#elementsFilesystems
This made it necessary to manually modify the libivrt-<UUID> profile.
There is a report about this on the Ubuntu bugtracker:
https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/943680
Ok, thanks for the extra information.
>
>> ---
>> src/security/virt-aa-helper.c | 26 ++++++++++++++++++++------
>> 1 file changed, 20 insertions(+), 6 deletions(-)
>>
>> diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
>> index b9282b4..e1f7848 100644
>> --- a/src/security/virt-aa-helper.c
>> +++ b/src/security/virt-aa-helper.c
>> @@ -578,9 +578,6 @@ valid_path(const char *path, const bool readonly)
>> return -1;
>>
>> switch (sb.st_mode & S_IFMT) {
>> - case S_IFDIR:
>> - return 1;
>> - break;
>> case S_IFSOCK:
>> return 1;
>> break;
>> @@ -747,7 +744,7 @@ get_definition(vahControl * ctl, const char *xmlStr)
>> }
>>
>> static int
>> -vah_add_file(virBufferPtr buf, const char *path, const char *perms)
>> +vah_add_path(virBufferPtr buf, const char *path, const char *perms, bool
recursive)
>> {
>> char *tmp = NULL;
>> int rc = -1;
>> @@ -788,10 +785,14 @@ vah_add_file(virBufferPtr buf, const char *path, const char
*perms)
>> goto cleanup;
>> }
>>
>> - virBufferAsprintf(buf, " \"%s\" %s,\n", tmp, perms);
>> + virBufferAsprintf(buf, " \"%s%s\" %s,\n", tmp,
recursive ? "/**" : "", perms);
>> if (readonly) {
>> virBufferAddLit(buf, " # don't audit writes to readonly
files\n");
>> - virBufferAsprintf(buf, " deny \"%s\" w,\n", tmp);
>> + virBufferAsprintf(buf, " deny \"%s%s\" w,\n", tmp,
recursive ? "/**" : "");
>> + }
>> + if (recursive) {
>> + // allow reading (but not creating) the dir
>> + virBufferAsprintf(buf, " \"%s/\" r,\n", tmp);
>> }
>>
>> cleanup:
>> @@ -801,6 +802,12 @@ vah_add_file(virBufferPtr buf, const char *path, const char
*perms)
>> }
>>
>> static int
>> +vah_add_file(virBufferPtr buf, const char *path, const char *perms)
>> +{
>> + return vah_add_path(buf, path, perms, false);
>> +}
>> +
>> +static int
>> vah_add_file_chardev(virBufferPtr buf,
>> const char *path,
>> const char *perms,
>> @@ -1049,6 +1056,13 @@ get_files(vahControl * ctl)
>> } /* switch */
>> }
>>
>> + for (i = 0; i < ctl->def->nfss; i++) {
>> + virDomainFSDefPtr fs = ctl->def->fss[i];
>> +
>> + if (vah_add_path(&buf, fs->src, fs->readonly ? "r" :
"rw", true) != 0)
>> + goto cleanup;
>> + }
>> +
>> if (ctl->newfile)
>> if (vah_add_file(&buf, ctl->newfile, "rw") != 0)
>> goto cleanup;
>>
I've not tested this personally, but the patch looks fine from an AppArmor and
virt-aa-helper perspective. The only bit I wasn't sure of was this last hunk of
the patch-- I'd like upstream to comment on the correctness of (at least) this
portion of the patch. I will say that I noticed the SElinux driver doesn't seem
to use ctl->def->nfss, etc at all-- perhaps because it assumes the filesystem to
be correctly labelled to begin with? (I didn't look any further than
security_selinux.c).
Conditional 'Acked-By: Jamie Strandboge <jamie(a)canonical.com>' provided
others
are ok with this last hunk.
--
Jamie Strandboge
http://www.ubuntu.com/