Re: [libvirt] [PATCH 2/3] virt-aa-helper: don't deny writes to readonly mounts

There is no need to deny writes on a readonly mount: write still won't be accepted, even if the user remounts the folder as RW in the guest as qemu sets the 9p mount as ro. This deny rule was leading to problems for example with readonly /: The qemu process had to write to a bunch of files in / like logs, sockets, etc. This deny rule was also preventing auditing of these denials, making it harder to debug. --- src/security/virt-aa-helper.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c index 5de56e5..a2d7226 100644 --- a/src/security/virt-aa-helper.c +++ b/src/security/virt-aa-helper.c @@ -1127,7 +1127,10 @@ get_files(vahControl * ctl) ctl->def->fss[i]->src) { virDomainFSDefPtr fs = ctl->def->fss[i]; - if (vah_add_path(&buf, fs->src, fs->readonly ? "r" : "rw", true) != 0) + /* We don't need to add deny rw rules for readonly mounts, + * this can only lead to troubles when mounting / readonly. + */ + if (vah_add_path(&buf, fs->src, "rw", true) != 0) goto cleanup; } }