Allow changing the file mode, UID, and GID through SETATTR.
This only really makes sense with allow-other, though (because without
it, the effective access mode is fixed to be 0600 (u+rw) with qemu's
user being the file's owner), so changing these stat fields is not
allowed without allow-other.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block/export/fuse.c | 48 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 37 insertions(+), 11 deletions(-)
diff --git a/block/export/fuse.c b/block/export/fuse.c
index 1d54286d90..742e0af657 100644
--- a/block/export/fuse.c
+++ b/block/export/fuse.c
@@ -47,6 +47,10 @@ typedef struct FuseExport {
bool writable;
bool growable;
bool allow_other;
+
+ mode_t st_mode;
+ uid_t st_uid;
+ gid_t st_gid;
} FuseExport;
static GHashTable *exports;
@@ -120,6 +124,13 @@ static int fuse_export_create(BlockExport *blk_exp,
exp->growable = args->growable;
exp->allow_other = args->allow_other;
+ exp->st_mode = S_IFREG | S_IRUSR;
+ if (exp->writable) {
+ exp->st_mode |= S_IWUSR;
+ }
+ exp->st_uid = getuid();
+ exp->st_gid = getgid();
+
ret = setup_fuse_export(exp, args->mountpoint, errp);
if (ret < 0) {
goto fail;
@@ -329,7 +340,6 @@ static void fuse_getattr(fuse_req_t req, fuse_ino_t inode,
int64_t length, allocated_blocks;
time_t now = time(NULL);
FuseExport *exp = fuse_req_userdata(req);
- mode_t mode;
length = blk_getlength(exp->common.blk);
if (length < 0) {
@@ -344,17 +354,12 @@ static void fuse_getattr(fuse_req_t req, fuse_ino_t inode,
allocated_blocks = DIV_ROUND_UP(allocated_blocks, 512);
}
- mode = S_IFREG | S_IRUSR;
- if (exp->writable) {
- mode |= S_IWUSR;
- }
-
statbuf = (struct stat) {
.st_ino = inode,
- .st_mode = mode,
+ .st_mode = exp->st_mode,
.st_nlink = 1,
- .st_uid = getuid(),
- .st_gid = getgid(),
+ .st_uid = exp->st_uid,
+ .st_gid = exp->st_gid,
.st_size = length,
.st_blksize = blk_bs(exp->common.blk)->bl.request_alignment,
.st_blocks = allocated_blocks,
@@ -400,15 +405,23 @@ static int fuse_do_truncate(const FuseExport *exp,
int64_t size,
}
/**
- * Let clients set file attributes. Only resizing is supported.
+ * Let clients set file attributes. With allow_other, only resizing and
+ * changing permissions (st_mode, st_uid, st_gid) is allowed. Without
+ * allow_other, only resizing is supported.
*/
static void fuse_setattr(fuse_req_t req, fuse_ino_t inode, struct stat
*statbuf,
int to_set, struct fuse_file_info *fi)
{
FuseExport *exp = fuse_req_userdata(req);
+ int supported_attrs;
int ret;
- if (to_set & ~FUSE_SET_ATTR_SIZE) {
+ supported_attrs = FUSE_SET_ATTR_SIZE;
+ if (exp->allow_other) {
+ supported_attrs |= FUSE_SET_ATTR_MODE | FUSE_SET_ATTR_UID |
+ FUSE_SET_ATTR_GID;
+ }
+ if (to_set & ~supported_attrs) {
fuse_reply_err(req, ENOTSUP);
return;
}
@@ -426,6 +439,19 @@ static void fuse_setattr(fuse_req_t req, fuse_ino_t inode,
struct stat *statbuf,
}
}
+ if (to_set & FUSE_SET_ATTR_MODE) {
+ /* Only allow changing the file mode, not the type */
+ exp->st_mode = (statbuf->st_mode & 07777) | S_IFREG;
+ }
