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[PATCH 1/4] export/fuse: Add allow-other option
From: |
Max Reitz |
Subject: |
[PATCH 1/4] export/fuse: Add allow-other option |
Date: |
Mon, 14 Jun 2021 16:44:04 +0200 |
Without the allow_other mount option, no user (not even root) but the
one who started qemu/the storage daemon can access the export. Allow
users to configure the export such that such accesses are possible.
When we do pass allow_other, we should also pass default_permissions,
because our export code performs no permission checks. With
default_permissions, we can just let the kernel do it.
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
qapi/block-export.json | 11 ++++++++++-
block/export/fuse.c | 17 +++++++++++++++--
2 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/qapi/block-export.json b/qapi/block-export.json
index e819e70cac..5d1cc04ac4 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -132,11 +132,20 @@
# @growable: Whether writes beyond the EOF should grow the block node
# accordingly. (default: false)
#
+# @allow-other: By default (if this is false), only qemu's user is allowed
+# access to this export. That cannot be changed even with
+# chmod or chown.
+# This option will allow other users access to the export with
the
+# FUSE mount options "allow_other,default_permissions".
+# (default_permissions enables standard UNIX permission checks.)
+# (since 6.1; default: false)
+#
# Since: 6.0
##
{ 'struct': 'BlockExportOptionsFuse',
'data': { 'mountpoint': 'str',
- '*growable': 'bool' },
+ '*growable': 'bool',
+ '*allow-other': 'bool' },
'if': 'defined(CONFIG_FUSE)' }
##
diff --git a/block/export/fuse.c b/block/export/fuse.c
index 38f74c94da..34a5836ece 100644
--- a/block/export/fuse.c
+++ b/block/export/fuse.c
@@ -46,6 +46,7 @@ typedef struct FuseExport {
char *mountpoint;
bool writable;
bool growable;
+ bool allow_other;
} FuseExport;
static GHashTable *exports;
@@ -117,6 +118,7 @@ static int fuse_export_create(BlockExport *blk_exp,
exp->mountpoint = g_strdup(args->mountpoint);
exp->writable = blk_exp_args->writable;
exp->growable = args->growable;
+ exp->allow_other = args->allow_other;
ret = setup_fuse_export(exp, args->mountpoint, errp);
if (ret < 0) {
@@ -150,11 +152,22 @@ static int setup_fuse_export(FuseExport *exp, const char
*mountpoint,
{
const char *fuse_argv[4];
char *mount_opts;
+ const char *allow_other;
struct fuse_args fuse_args;
int ret;
- /* Needs to match what fuse_init() sets. Only max_read must be supplied.
*/
- mount_opts = g_strdup_printf("max_read=%zu", FUSE_MAX_BOUNCE_BYTES);
+ if (exp->allow_other) {
+ allow_other = ",allow_other,default_permissions";
+ } else {
+ allow_other = "";
+ }
+
+ /*
+ * max_read needs to match what fuse_init() sets.
+ * max_write need not be supplied.
+ */
+ mount_opts = g_strdup_printf("max_read=%zu%s", FUSE_MAX_BOUNCE_BYTES,
+ allow_other);
fuse_argv[0] = ""; /* Dummy program name */
fuse_argv[1] = "-o";
--
2.31.1