[libvirt] [PATCH] qemu: drop unused arguments for dump-guest-memory

[Osier Yang]

On 2012年09月18日 03:08, Eric Blake wrote:
> Upstream qemu has raised a concern about whether dumping guest
> memory by reading guest paging tables is a security hole:
> https://lists.gnu.org/archive/html/qemu-devel/2012-09/msg02607.html
>
> While auditing libvirt to see if we would be impacted, I noticed
> that we had some dead code.  It is simpler to nuke the dead code
> and limit our monitor code to just the subset we make use of.
>
> * src/qemu/qemu_monitor.h (QEMU_MONITOR_DUMP): Drop poorly named
> and mostly-unused enum.
> * src/qemu/qemu_monitor.c (qemuMonitorDumpToFd): Drop arguments.
> * src/qemu/qemu_monitor_json.h (qemuMonitorJSONDump): Likewise.
> * src/qemu/qemu_monitor_json.c (qemuMonitorJSONDump): Likewise.
> * src/qemu/qemu_driver.c (qemuDumpToFd): Update caller.
> ---
>   src/qemu/qemu_driver.c       |  2 +-
>   src/qemu/qemu_monitor.c      | 12 ++++--------
>   src/qemu/qemu_monitor.h      | 11 +----------
>   src/qemu/qemu_monitor_json.c | 24 +++++++-----------------
>   src/qemu/qemu_monitor_json.h |  5 +----
>   5 files changed, 14 insertions(+), 40 deletions(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index f14c220..e6e5d02 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -3136,7 +3136,7 @@ static int qemuDumpToFd(struct qemud_driver *driver, virDomainObjPtr vm,
>       if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob)<  0)
>           return -1;
>
> -    ret = qemuMonitorDumpToFd(priv->mon, 0, fd, 0, 0);
> +    ret = qemuMonitorDumpToFd(priv->mon, fd);
>       qemuDomainObjExitMonitorWithDriver(driver, vm);
>
>       return ret;
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index b7730fd..b772b28 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -2045,15 +2045,11 @@ int qemuMonitorMigrateCancel(qemuMonitorPtr mon)
>       return ret;
>   }
>
> -int qemuMonitorDumpToFd(qemuMonitorPtr mon,
> -                        unsigned int flags,
> -                        int fd,
> -                        unsigned long long begin,
> -                        unsigned long long length)
> +int
> +qemuMonitorDumpToFd(qemuMonitorPtr mon, int fd)
>   {
>       int ret;
> -    VIR_DEBUG("mon=%p fd=%d flags=%x begin=%llx length=%llx",
> -              mon, fd, flags, begin, length);
> +    VIR_DEBUG("mon=%p fd=%d", mon, fd);
>
>       if (!mon) {
>           virReportError(VIR_ERR_INVALID_ARG, "%s",
> @@ -2073,7 +2069,7 @@ int qemuMonitorDumpToFd(qemuMonitorPtr mon,
>       if (qemuMonitorSendFileHandle(mon, "dump", fd)<  0)
>           return -1;
>
> -    ret = qemuMonitorJSONDump(mon, flags, "fd:dump", begin, length);
> +    ret = qemuMonitorJSONDump(mon, "fd:dump");
>
>       if (ret<  0) {
>           if (qemuMonitorCloseFileHandle(mon, "dump")<  0)
> diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
> index e37dac8..232ae96 100644
> --- a/src/qemu/qemu_monitor.h
> +++ b/src/qemu/qemu_monitor.h
> @@ -387,17 +387,8 @@ int qemuMonitorMigrateToUnix(qemuMonitorPtr mon,
>
>   int qemuMonitorMigrateCancel(qemuMonitorPtr mon);
>
> -typedef enum {
> -  QEMU_MONITOR_DUMP_HAVE_FILTER  = 1<<  0,
> -  QEMU_MONITOR_DUMP_PAGING       = 1<<  1,
> -  QEMU_MONITOR_DUMP_FLAGS_LAST
> -} QEMU_MONITOR_DUMP;
> -
>   int qemuMonitorDumpToFd(qemuMonitorPtr mon,
> -                        unsigned int flags,
> -                        int fd,
> -                        unsigned long long begin,
> -                        unsigned long long length);
> +                        int fd);
>
>   int qemuMonitorGraphicsRelocate(qemuMonitorPtr mon,
>                                   int type,
> diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
> index b23be1e..a5198b0 100644
> --- a/src/qemu/qemu_monitor_json.c
> +++ b/src/qemu/qemu_monitor_json.c
> @@ -2552,28 +2552,18 @@ int qemuMonitorJSONMigrateCancel(qemuMonitorPtr mon)
>       return ret;
>   }
>
> -int qemuMonitorJSONDump(qemuMonitorPtr mon,
> -                        unsigned int flags,
> -                        const char *protocol,
> -                        unsigned long long begin,
> -                        unsigned long long length)
> +int
> +qemuMonitorJSONDump(qemuMonitorPtr mon,
> +                    const char *protocol)
>   {
>       int ret;
>       virJSONValuePtr cmd = NULL;
>       virJSONValuePtr reply = NULL;
>
> -    if (flags&  QEMU_MONITOR_DUMP_HAVE_FILTER)
> -        cmd = qemuMonitorJSONMakeCommand("dump-guest-memory",
> -                                         "b:paging", flags&  QEMU_MONITOR_DUMP_PAGING ? 1 : 0,
> -                                         "s:protocol", protocol,
> -                                         "U:begin", begin,
> -                                         "U:length", length,
> -                                         NULL);
> -    else
> -        cmd = qemuMonitorJSONMakeCommand("dump-guest-memory",
> -                                         "b:paging", flags&  QEMU_MONITOR_DUMP_PAGING ? 1 : 0,
> -                                         "s:protocol", protocol,
> -                                         NULL);
> +    cmd = qemuMonitorJSONMakeCommand("dump-guest-memory",
> +                                     "b:paging", false,
> +                                     "s:protocol", protocol,
> +                                     NULL);
>       if (!cmd)
>           return -1;
>
> diff --git a/src/qemu/qemu_monitor_json.h b/src/qemu/qemu_monitor_json.h
> index bdcf819..b592d12 100644
> --- a/src/qemu/qemu_monitor_json.h
> +++ b/src/qemu/qemu_monitor_json.h
> @@ -138,10 +138,7 @@ int qemuMonitorJSONMigrate(qemuMonitorPtr mon,
>   int qemuMonitorJSONMigrateCancel(qemuMonitorPtr mon);
>
>   int qemuMonitorJSONDump(qemuMonitorPtr mon,
> -                        unsigned int flags,
> -                        const char *protocol,
> -                        unsigned long long begin,
> -                        unsigned long long length);
> +                        const char *protocol);
>
>   int qemuMonitorJSONGraphicsRelocate(qemuMonitorPtr mon,
>                                       int type,

ACK.