similar to: [nbdkit PATCH] iso: Shell-quote an alternative isoprog

On 6/26/19 11:53 AM, Eric Blake wrote: > Otherwise, a user can do things like "nbdkit iso . prog='date;prog'" > to run unintended commands in addition to their alternative isoprog. On the other hand, allowing: prog='isoprog --parameter' may be intentional, and I just broke that. Maybe I need to revert this? > This is not a CVE (since nbdkit isn't running

The plugin should now support pre-fetch and extents, although most ISO images will be non-sparse so extents probably isn't that useful. --- plugins/iso/Makefile.am | 4 +- plugins/iso/iso.c | 99 +++++++++++++++++++---------------------- 2 files changed, 48 insertions(+), 55 deletions(-) diff --git a/plugins/iso/Makefile.am b/plugins/iso/Makefile.am index a0fd337a..44ecbc8a 100644 ---

Since v1: - new patch to add uri_quote() - rebase on top of other recent patches needed while auditing shell_quote() - use uri_quote() instead of shell_quote() for producing $uri Eric Blake (2): common/utils: Add uri_quote and tests captive: Support $uri in --run docs/nbdkit-captive.pod | 8 ++- common/utils/utils.h | 1 + common/utils/test-quotes.c | 108

The existing --run '$nbd' outputs an older form that differs between libguestfs and qemu, and which is not always a valid URI. For historical compatibility, we probably can't change that; but we can instead add a new '$uri' that outputs a valid URI. Note that the libguestfs '$nbd' TCP form is already a valid URI, but that libguestfs still needs to be taught about the

Another interesting thing you can do with this plugin: https://rwmj.wordpress.com/2019/02/19/nbdkit-linuxdisk-plugin/ v2: - Fix inconsistent tab/space. - All 3 plugins now contain a block of text pointing to the other 2 plugins. - TMDIR -> TMPDIR - Unlink the temporary file and other cleanups along error paths. - fclose -> pclose, and check the return value for errors. -

These plugins have in common that they store either a list of allocated strings or a list of constant strings. Define either string_vector or const_string_vector as appropriate and use it to store these lists. --- plugins/iso/Makefile.am | 1 + plugins/split/Makefile.am | 1 + plugins/floppy/virtual-floppy.h | 7 +++-- plugins/floppy/directory-lfn.c | 35 +++++++++-------------

Turns out Japanese trains are good for coding! In supermin we have a bunch of code to create the libguestfs appliance. It creates it directly using libext2fs (part of e2fsprogs). We can use the same technique to create ext2 virtual disks in nbdkit, which is what this new plugin does. Why a new plugin instead of modifying the floppy plugin? See the 4/4 commit message for an explanation. The

From: "Richard W.M. Jones" <rjones@redhat.com> The shell_quote function is moved to a new common/utils directory. Eventually more utility functions can be created here. This change is pure refactoring. --- Makefile.am | 1 + common/utils/Makefile.am | 41 ++++++++++++++++++++++++++++ common/utils/utils.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++

An evolution of v1 here: https://www.redhat.com/archives/libguestfs/2020-April/msg00035.html I want to generalize the tmpdisk plugin, particularly so you can use commands like ‘qemu-img create’ or even ‘virt-builder’. (Actually virt-builder really works - I tested it - but of course it causes a 30+ second delay when connecting to the server.) You can now use commands such as: nbdkit tmpdisk

This was a rather longer trip around the houses than I anticipated! The basic purpose of the patch series is to set $nbdkit_stdio_safe to "0" or "1" in sh and eval plugin scripts. To do that, I ended up adding a nicer way to manipulate environ lists, and to do that, I ended up adding a whole generic vector implementation which is applicable in a lot of different places.

For v3 I reimplemented this using mke2fs -d. This obviously makes the implementation a whole lot simpler, but cannot support multiple directory merging. Patches 1-3 are the same as before. I've also reproduced the notes from v2 below. v2: - Fix inconsistent tab/space. - All 3 plugins now contain a block of text pointing to the other 2 plugins. - TMDIR -> TMPDIR - Unlink the

I like this change. I think we were overloading the config_complete method before to do two different things (complete configuration; do any allocation/housekeeping necessary before we can start serving). The only questions in my mind are whether we want this before 1.18, and whether the name ("get_ready") is a good one. Rich.

Patch 1/2 is uncontroversial. Patch 2/2 is an interesting idea I had to generalize this plugin. It already uses a complete embedded shell script to do most of the work. What if, instead of making special cases for "type" and "label" params, we simply turn any other plugin parameters into script variables? This part of it works fine. However there is another problem which is

v2 was here: https://www.redhat.com/archives/libguestfs/2020-April/msg00075.html In v3: - Add [VAR=VALUE ...] to manual. - Various minor improvements to the manual. - Work (at least, in theory - not tested) with block devices or symlinks. I didn't document this because it's hard to ensure these files or block devices would be cleaned up, so here be dragons. - Remove O_NOCTTY. -

This parameter provided a name for the "default export" -- ie. the one and only export returned to the client by NBD_OPT_LIST. But nbdkit traditionally didn't care what export name the client requested. Since 1.16 plugins have been able to serve different content per export name (and return errors for unknown exports), but the -e option didn't reflect that and only created

This can be used for creating temporary disks to thin clients, as a kind of "remote tmpfs". See also: https://www.redhat.com/archives/libguestfs/2020-March/msg00134.html --- plugins/data/nbdkit-data-plugin.pod | 1 + plugins/file/nbdkit-file-plugin.pod | 1 + plugins/linuxdisk/nbdkit-linuxdisk-plugin.pod | 7 +- plugins/memory/nbdkit-memory-plugin.pod |

Unfinished (needs tests). This is my attempt to make a "remote tmpfs" plugin as outlined in this prior email: https://www.redhat.com/archives/libguestfs/2020-March/msg00134.html Although it would be possible to construct something a bit like this using existing plugins and filters (perhaps with some new features in those filters) I think it may be nicer to have a dedicated plugin for

This allows us to be much more flexible about what commands can be used. It also means we do not need to encode any special behaviour for type or label parameters. XXX However one problem which is not addressed here: The $disk passed to the shell script fragment must be updated, not replaced. This is because currently the plugin has a file descriptor opened on this file. If it is deleted by

Needs some work still, see in particular the commit message for patch 3. Rich.

For context see these threads: https://lists.gnu.org/archive/html/qemu-discuss/2020-06/threads.html#00053 https://lists.gnu.org/archive/html/qemu-block/2020-06/threads.html#01496 Rich.