From b64ec4e4ade581d662753cdeb0d7e0e27aafbf81 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Wed, 29 May 2013 19:35:40 +0800 Subject: [PATCH] block: add block driver read only whitelist 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 Signed-off-by: Kevin Wolf --- block.c | 43 +++++++++++++++++++++++++++---------------- blockdev.c | 4 ++-- configure | 20 +++++++++++++++----- hw/block/xen_disk.c | 8 ++++++-- include/block/block.h | 3 ++- scripts/create_config | 11 +++++++++-- 6 files changed, 61 insertions(+), 28 deletions(-) diff --git a/block.c b/block.c index 3f87489937..65c0b60736 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 d1ec99af73..b9b2d10e6b 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; @@ -1096,7 +1096,7 @@ 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 70c41b0fad..1654413762 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" ;; @@ -1049,7 +1052,12 @@ 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" @@ -3481,7 +3489,8 @@ 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 $vnc" @@ -3662,7 +3671,8 @@ fi if test "$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 0ac65d4e8f..247f32f4ee 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 1251c5cf9f..5604418a6a 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 c471e8caf9..258513a887 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