On Mon, Oct 12, 2020 at 05:21:15PM +0100, Dr. David Alan Gilbert wrote: > * Tobin Feldman-Fitzthum ([email protected]) wrote: > > AMD SEV allows a guest owner to inject a secret blob > > into the memory of a virtual machine. The secret is > > encrypted with the SEV Transport Encryption Key and > > integrity is guaranteed with the Transport Integrity > > Key. Although QEMU faciliates the injection of the
Trivial typo s/faciliates/facilitates/ > > launch secret, it cannot access the secret. > > > > Signed-off-by: Tobin Feldman-Fitzthum <[email protected]> > > --- > > include/monitor/monitor.h | 3 ++ > > include/sysemu/sev.h | 2 ++ > > monitor/misc.c | 8 ++--- > > qapi/misc-target.json | 18 +++++++++++ > > target/i386/monitor.c | 9 ++++++ > > target/i386/sev-stub.c | 5 +++ > > target/i386/sev.c | 66 +++++++++++++++++++++++++++++++++++++++ > > target/i386/trace-events | 1 + > > 8 files changed, 108 insertions(+), 4 deletions(-) > > diff --git a/qapi/misc-target.json b/qapi/misc-target.json > > index dee3b45930..d145f916b3 100644 > > --- a/qapi/misc-target.json > > +++ b/qapi/misc-target.json > > @@ -200,6 +200,24 @@ > > { 'command': 'query-sev-capabilities', 'returns': 'SevCapability', > > 'if': 'defined(TARGET_I386)' } > > > > +## > > +# @sev-inject-launch-secret: > > +# > > +# This command injects a secret blob into memory of SEV guest. > > +# > > +# @packet-header: the launch secret packet header encoded in base64 > > +# > > +# @secret: the launch secret data to be injected encoded in base64 Just to double check, this "secret" is /not/ in clear text, so there's no way either QEMU nor the QMP client can access sensitive info, right ? If 'secret' was clear text, then we would need to pass the data across QMP in a different way. > > +# > > +# @gpa: the guest physical address where secret will be injected. > > +# > > +# Since: 5.1 s/5.1/5.2/ > > +# > > +## > > +{ 'command': 'sev-inject-launch-secret', > > + 'data': { 'packet-header': 'str', 'secret': 'str', 'gpa': 'uint64' }, > > + 'if': 'defined(TARGET_I386)' } > > + > > ## > > # @dump-skeys: > > # > > diff --git a/target/i386/monitor.c b/target/i386/monitor.c > > index 27ebfa3ad2..42bcfe6dc0 100644 > > --- a/target/i386/monitor.c > > +++ b/target/i386/monitor.c > > @@ -736,3 +736,12 @@ SevCapability *qmp_query_sev_capabilities(Error **errp) > > > > return data; > > } > > + > > +void qmp_sev_inject_launch_secret(const char *packet_hdr, > > + const char *secret, uint64_t gpa, > > + Error **errp) > > +{ > > + if (sev_inject_launch_secret(packet_hdr, secret, gpa) != 0) { > > + error_setg(errp, "SEV inject secret failed"); This generic error message is useless - sev_inject_launch_secret() needs to take the 'errp' parameter and report what actually failed. > > + } > > +} > > diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c > > index e5ee13309c..fed4588185 100644 > > --- a/target/i386/sev-stub.c > > +++ b/target/i386/sev-stub.c > > @@ -48,3 +48,8 @@ SevCapability *sev_get_capabilities(void) > > { > > return NULL; > > } > > +int sev_inject_launch_secret(const char *hdr, const char *secret, > > + uint64_t gpa) > > +{ > > + return 1; > > +} > > diff --git a/target/i386/sev.c b/target/i386/sev.c > > index d273174ad3..cbeb8f2e02 100644 > > --- a/target/i386/sev.c > > +++ b/target/i386/sev.c > > @@ -28,6 +28,8 @@ > > #include "sysemu/runstate.h" > > #include "trace.h" > > #include "migration/blocker.h" > > +#include "exec/address-spaces.h" > > +#include "monitor/monitor.h" > > > > #define TYPE_SEV_GUEST "sev-guest" > > #define SEV_GUEST(obj) \ > > @@ -769,6 +771,70 @@ sev_encrypt_data(void *handle, uint8_t *ptr, uint64_t > > len) > > return 0; > > } > > > > +int sev_inject_launch_secret(const char *packet_hdr, > > + const char *secret, uint64_t gpa) > > +{ > > + struct kvm_sev_launch_secret input; > > + guchar *data = NULL, *hdr = NULL; If you declare with 'g_autofree' you don't need the manual 'g_free' calls later. This in turn means you can get rid of the "goto err" jumps and instead directly return. > > + int error, ret = 1; > > + void *hva; > > + gsize hdr_sz = 0, data_sz = 0; > > + Error *local_err = NULL; Declare with g_autoptr(Error) local_err = NULL to fix the leak David mentions > > + MemoryRegion *mr = NULL; > > + > > + /* secret can be inject only in this state */ > > + if (!sev_check_state(sev_guest, SEV_STATE_LAUNCH_SECRET)) { > > + error_report("SEV: Not in correct state. (LSECRET) %x", > > + sev_guest->state); > > + return 1; > > + } > > + > > + hdr = g_base64_decode(packet_hdr, &hdr_sz); > > + if (!hdr || !hdr_sz) { > > + error_report("SEV: Failed to decode sequence header"); > > + return 1; > > + } > > + > > + data = g_base64_decode(secret, &data_sz); > > + if (!data || !data_sz) { > > + error_report("SEV: Failed to decode data"); > > + goto err; > > + } > > + > > + hva = gpa2hva(&mr, gpa, data_sz, &local_err); > > + if (!hva) { > > + error_report("SEV: Failed to calculate guest address."); > > Note this is leaking local_err; you need to turn that into probably an > error_reportf_err(local_err, "SEV: Failed to calculate guest address:"); Actually this method needs to take an "Error **errp" parameter, so that the error is propagated back to the QMP command handler, and from there back to the client app. > Also the '5.1' above needs to change to 5.2. > > I think with that it looks OK to me. > > + goto err; > > + } > > + > > + input.hdr_uaddr = (uint64_t)(unsigned long)hdr; > > + input.hdr_len = hdr_sz; > > + > > + input.trans_uaddr = (uint64_t)(unsigned long)data; > > + input.trans_len = data_sz; > > + > > + input.guest_uaddr = (uint64_t)(unsigned long)hva; > > + input.guest_len = data_sz; > > + > > + trace_kvm_sev_launch_secret(gpa, input.guest_uaddr, > > + input.trans_uaddr, input.trans_len); > > + > > + ret = sev_ioctl(sev_guest->sev_fd, KVM_SEV_LAUNCH_SECRET, > > + &input, &error); > > + if (ret) { > > + error_report("SEV: failed to inject secret ret=%d fw_error=%d > > '%s'", > > + ret, error, fw_error_to_str(error)); > > + goto err; > > + } > > + > > + ret = 0; > > + > > +err: > > + g_free(data); > > + g_free(hdr); > > + return ret; > > +} Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
