From e04d52892c7fcd0e2ec70f77f3e5b934d45918c8 Mon Sep 17 00:00:00 2001

From: Miroslav Rezanina <mrezanin@redhat.com>

Date: Wed, 31 Jul 2013 09:56:17 +0200

Subject: block: add block driver read only whitelist

Message-id: <6873f36f1d3c26ad7b84bf2150c0a98afd6c5e72.1375208619.git.mrezanin@redhat.com>

Patchwork-id: 52827

O-Subject: [RHEL7 qemu-kvm PATCH 4.5/5] block: add block driver read only whitelist

Bugzilla: 836675

RH-Acked-by: Fam Zheng <famz@redhat.com>

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

RH-Acked-by: Michal Novotny <minovotn@redhat.com>

From: Fam Zheng <famz@redhat.com>

This is missing patch required for "VMDK Backports and Spec Update" serie.

We may want to include a driver in the whitelist for read only tasks

such as diagnosing or exporting guest data (with libguestfs as a good

example). This patch introduces a readonly whitelist option, and for

backward compatibility, the old configure option --block-drv-whitelist

is now an alias to rw whitelist.

Drivers in readonly list is only permitted to open file readonly, and

returns -ENOTSUP for RW opening.

E.g. To include vmdk readonly, and others read+write:

    ./configure --target-list=x86_64-softmmu \

                --block-drv-rw-whitelist=qcow2,raw,file,qed \

                --block-drv-ro-whitelist=vmdk

Signed-off-by: Fam Zheng <famz@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit b64ec4e4ade581d662753cdeb0d7e0e27aafbf81)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

diff --git a/block.c b/block.c

index 3f87489..65c0b60 100644

--- a/block.c

+++ b/block.c

@@ -328,28 +328,40 @@ BlockDriver *bdrv_find_format(const char *format_name)

     return NULL;

 }

-static int bdrv_is_whitelisted(BlockDriver *drv)

+static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)

 {

-    static const char *whitelist[] = {

-        CONFIG_BDRV_WHITELIST

+    static const char *whitelist_rw[] = {

+        CONFIG_BDRV_RW_WHITELIST

+    };

+    static const char *whitelist_ro[] = {

+        CONFIG_BDRV_RO_WHITELIST

     };

     const char **p;

-    if (!whitelist[0])

+    if (!whitelist_rw[0] && !whitelist_ro[0]) {

         return 1;               /* no whitelist, anything goes */

+    }

-    for (p = whitelist; *p; p++) {

+    for (p = whitelist_rw; *p; p++) {

         if (!strcmp(drv->format_name, *p)) {

             return 1;

         }

     }

+    if (read_only) {

+        for (p = whitelist_ro; *p; p++) {

+            if (!strcmp(drv->format_name, *p)) {

+                return 1;

+            }

+        }

+    }

     return 0;

 }

-BlockDriver *bdrv_find_whitelisted_format(const char *format_name)

+BlockDriver *bdrv_find_whitelisted_format(const char *format_name,

+                                          bool read_only)

 {

     BlockDriver *drv = bdrv_find_format(format_name);

-    return drv && bdrv_is_whitelisted(drv) ? drv : NULL;

+    return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL;

 }

 typedef struct CreateCo {

@@ -684,10 +696,6 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,

     trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);

-    if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {

-        return -ENOTSUP;

-    }

-

     /* bdrv_open() with directly using a protocol as drv. This layer is already

      * opened, so assign it to bs (while file becomes a closed BlockDriverState)

      * and return immediately. */

@@ -698,9 +706,15 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,

     bs->open_flags = flags;

     bs->buffer_alignment = 512;

+    open_flags = bdrv_open_flags(bs, flags);

+    bs->read_only = !(open_flags & BDRV_O_RDWR);

+

+    if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {

+        return -ENOTSUP;

+    }

     assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */

-    if ((flags & BDRV_O_RDWR) && (flags & BDRV_O_COPY_ON_READ)) {

+    if (!bs->read_only && (flags & BDRV_O_COPY_ON_READ)) {

         bdrv_enable_copy_on_read(bs);

     }

@@ -714,9 +728,6 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,

     bs->opaque = g_malloc0(drv->instance_size);

     bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB);

-    open_flags = bdrv_open_flags(bs, flags);

-

-    bs->read_only = !(open_flags & BDRV_O_RDWR);

     /* Open the image, either directly or using a protocol */

     if (drv->bdrv_file_open) {

@@ -801,7 +812,7 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename,

     /* Find the right block driver */

     drvname = qdict_get_try_str(options, "driver");

     if (drvname) {

-        drv = bdrv_find_whitelisted_format(drvname);

+        drv = bdrv_find_whitelisted_format(drvname, !(flags & BDRV_O_RDWR));

         qdict_del(options, "driver");

     } else if (filename) {

         drv = bdrv_find_protocol(filename);

diff --git a/blockdev.c b/blockdev.c

index 625d041..6500c47 100644

--- a/blockdev.c

+++ b/blockdev.c

@@ -477,7 +477,7 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)

             error_printf("\n");

             return NULL;

         }

-        drv = bdrv_find_whitelisted_format(buf);

+        drv = bdrv_find_whitelisted_format(buf, ro);

         if (!drv) {

             error_report("'%s' invalid format", buf);

             return NULL;

@@ -1024,7 +1024,7 @@ void qmp_change_blockdev(const char *device, const char *filename,

     }

     if (format) {

-        drv = bdrv_find_whitelisted_format(format);

+        drv = bdrv_find_whitelisted_format(format, bs->read_only);

         if (!drv) {

             error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);

             return;

diff --git a/configure b/configure

index eb74510..a71e8a1 100755

--- a/configure

+++ b/configure

@@ -123,7 +123,8 @@ interp_prefix="/usr/gnemul/qemu-%M"

 static="no"

 cross_prefix=""

 audio_drv_list=""

-block_drv_whitelist=""

+block_drv_rw_whitelist=""

+block_drv_ro_whitelist=""

 host_cc="cc"

 libs_softmmu=""

 libs_tools=""

@@ -708,7 +709,9 @@ for opt do

   ;;

   --audio-drv-list=*) audio_drv_list="$optarg"

   ;;

-  --block-drv-whitelist=*) block_drv_whitelist=`echo "$optarg" | sed -e 's/,/ /g'`

+  --block-drv-rw-whitelist=*|--block-drv-whitelist=*) block_drv_rw_whitelist=`echo "$optarg" | sed -e 's/,/ /g'`

+  ;;

+  --block-drv-ro-whitelist=*) block_drv_ro_whitelist=`echo "$optarg" | sed -e 's/,/ /g'`

   ;;

   --enable-debug-tcg) debug_tcg="yes"

   ;;

@@ -1105,7 +1108,12 @@ echo "  --disable-cocoa          disable Cocoa (Mac OS X only)"

 echo "  --enable-cocoa           enable Cocoa (default on Mac OS X)"

 echo "  --audio-drv-list=LIST    set audio drivers list:"

 echo "                           Available drivers: $audio_possible_drivers"

-echo "  --block-drv-whitelist=L  set block driver whitelist"

+echo "  --block-drv-whitelist=L  Same as --block-drv-rw-whitelist=L"

+echo "  --block-drv-rw-whitelist=L"

+echo "                           set block driver read-write whitelist"

+echo "                           (affects only QEMU, not qemu-img)"

+echo "  --block-drv-ro-whitelist=L"

+echo "                           set block driver read-only whitelist"

 echo "                           (affects only QEMU, not qemu-img)"

 echo "  --enable-mixemu          enable mixer emulation"

 echo "  --disable-xen            disable xen backend driver support"

@@ -3525,7 +3533,8 @@ echo "curses support    $curses"

 echo "curl support      $curl"

 echo "mingw32 support   $mingw32"

 echo "Audio drivers     $audio_drv_list"

-echo "Block whitelist   $block_drv_whitelist"

+echo "Block whitelist (rw) $block_drv_rw_whitelist"

+echo "Block whitelist (ro) $block_drv_ro_whitelist"

 echo "Mixer emulation   $mixemu"

 echo "VirtFS support    $virtfs"

 echo "VNC support       $vnc"

@@ -3704,7 +3713,8 @@ fi

 if test "$audio_win_int" = "yes" ; then

   echo "CONFIG_AUDIO_WIN_INT=y" >> $config_host_mak

 fi

-echo "CONFIG_BDRV_WHITELIST=$block_drv_whitelist" >> $config_host_mak

+echo "CONFIG_BDRV_RW_WHITELIST=$block_drv_rw_whitelist" >> $config_host_mak

+echo "CONFIG_BDRV_RO_WHITELIST=$block_drv_ro_whitelist" >> $config_host_mak

 if test "$mixemu" = "yes" ; then

   echo "CONFIG_MIXEMU=y" >> $config_host_mak

 fi

diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c

index 0ac65d4..247f32f 100644

--- a/hw/block/xen_disk.c

+++ b/hw/block/xen_disk.c

@@ -780,11 +780,13 @@ static int blk_connect(struct XenDevice *xendev)

 {

     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);

     int pers, index, qflags;

+    bool readonly = true;

     /* read-only ? */

     qflags = BDRV_O_CACHE_WB | BDRV_O_NATIVE_AIO;

     if (strcmp(blkdev->mode, "w") == 0) {

         qflags |= BDRV_O_RDWR;

+        readonly = false;

     }

     /* init qemu block driver */

@@ -795,8 +797,10 @@ static int blk_connect(struct XenDevice *xendev)

         xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");

         blkdev->bs = bdrv_new(blkdev->dev);

         if (blkdev->bs) {

-            if (bdrv_open(blkdev->bs, blkdev->filename, NULL, qflags,

-                        bdrv_find_whitelisted_format(blkdev->fileproto)) != 0) {

+            BlockDriver *drv = bdrv_find_whitelisted_format(blkdev->fileproto,

+                                                           readonly);

+            if (bdrv_open(blkdev->bs,

+                          blkdev->filename, NULL, qflags, drv) != 0) {

                 bdrv_delete(blkdev->bs);

                 blkdev->bs = NULL;

             }

diff --git a/include/block/block.h b/include/block/block.h

index 1251c5c..5604418 100644

--- a/include/block/block.h

+++ b/include/block/block.h

@@ -124,7 +124,8 @@ void bdrv_init(void);

 void bdrv_init_with_whitelist(void);

 BlockDriver *bdrv_find_protocol(const char *filename);

 BlockDriver *bdrv_find_format(const char *format_name);

-BlockDriver *bdrv_find_whitelisted_format(const char *format_name);

+BlockDriver *bdrv_find_whitelisted_format(const char *format_name,

+                                          bool readonly);

 int bdrv_create(BlockDriver *drv, const char* filename,

     QEMUOptionParameter *options);

 int bdrv_create_file(const char* filename, QEMUOptionParameter *options);

diff --git a/scripts/create_config b/scripts/create_config

index c471e8c..258513a 100755

--- a/scripts/create_config

+++ b/scripts/create_config

@@ -34,8 +34,15 @@ case $line in

     done

     echo ""

     ;;

- CONFIG_BDRV_WHITELIST=*)

-    echo "#define CONFIG_BDRV_WHITELIST \\"

+ CONFIG_BDRV_RW_WHITELIST=*)

+    echo "#define CONFIG_BDRV_RW_WHITELIST\\"

+    for drv in ${line#*=}; do

+      echo "    \"${drv}\",\\"

+    done

+    echo "    NULL"

+    ;;

+ CONFIG_BDRV_RO_WHITELIST=*)

+    echo "#define CONFIG_BDRV_RO_WHITELIST\\"

     for drv in ${line#*=}; do

       echo "    \"${drv}\",\\"

     done