|
 |
1d442b |
From: Stefan Hajnoczi <stefanha@redhat.com>
|
|
|
1d442b |
Date: Mon, 27 Jan 2020 19:02:20 +0000
|
|
|
1d442b |
Subject: [PATCH] virtiofsd: prevent FUSE_INIT/FUSE_DESTROY races
|
|
|
1d442b |
|
|
|
1d442b |
When running with multiple threads it can be tricky to handle
|
|
|
1d442b |
FUSE_INIT/FUSE_DESTROY in parallel with other request types or in
|
|
|
1d442b |
parallel with themselves. Serialize FUSE_INIT and FUSE_DESTROY so that
|
|
|
1d442b |
malicious clients cannot trigger race conditions.
|
|
|
1d442b |
|
|
|
1d442b |
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
|
|
|
1d442b |
Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
|
|
|
1d442b |
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
|
|
|
1d442b |
(cherry picked from commit cdc497c6925be745bc895355bd4674a17a4b2a8b)
|
|
|
1d442b |
---
|
|
|
1d442b |
tools/virtiofsd/fuse_i.h | 1 +
|
|
|
1d442b |
tools/virtiofsd/fuse_lowlevel.c | 18 ++++++++++++++++++
|
|
|
1d442b |
2 files changed, 19 insertions(+)
|
|
|
1d442b |
|
|
|
1d442b |
diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
|
|
|
1d442b |
index a20854f1c4..1447d86866 100644
|
|
|
1d442b |
--- a/tools/virtiofsd/fuse_i.h
|
|
|
1d442b |
+++ b/tools/virtiofsd/fuse_i.h
|
|
|
1d442b |
@@ -61,6 +61,7 @@ struct fuse_session {
|
|
|
1d442b |
struct fuse_req list;
|
|
|
1d442b |
struct fuse_req interrupts;
|
|
|
1d442b |
pthread_mutex_t lock;
|
|
|
1d442b |
+ pthread_rwlock_t init_rwlock;
|
|
|
1d442b |
int got_destroy;
|
|
|
1d442b |
int broken_splice_nonblock;
|
|
|
1d442b |
uint64_t notify_ctr;
|
|
|
1d442b |
diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
|
|
|
1d442b |
index dab6a31e08..79a4031266 100644
|
|
|
1d442b |
--- a/tools/virtiofsd/fuse_lowlevel.c
|
|
|
1d442b |
+++ b/tools/virtiofsd/fuse_lowlevel.c
|
|
|
1d442b |
@@ -2428,6 +2428,19 @@ void fuse_session_process_buf_int(struct fuse_session *se,
|
|
|
1d442b |
req->ctx.pid = in->pid;
|
|
|
1d442b |
req->ch = ch;
|
|
|
1d442b |
|
|
|
1d442b |
+ /*
|
|
|
1d442b |
+ * INIT and DESTROY requests are serialized, all other request types
|
|
|
1d442b |
+ * run in parallel. This prevents races between FUSE_INIT and ordinary
|
|
|
1d442b |
+ * requests, FUSE_INIT and FUSE_INIT, FUSE_INIT and FUSE_DESTROY, and
|
|
|
1d442b |
+ * FUSE_DESTROY and FUSE_DESTROY.
|
|
|
1d442b |
+ */
|
|
|
1d442b |
+ if (in->opcode == FUSE_INIT || in->opcode == CUSE_INIT ||
|
|
|
1d442b |
+ in->opcode == FUSE_DESTROY) {
|
|
|
1d442b |
+ pthread_rwlock_wrlock(&se->init_rwlock);
|
|
|
1d442b |
+ } else {
|
|
|
1d442b |
+ pthread_rwlock_rdlock(&se->init_rwlock);
|
|
|
1d442b |
+ }
|
|
|
1d442b |
+
|
|
|
1d442b |
err = EIO;
|
|
|
1d442b |
if (!se->got_init) {
|
|
|
1d442b |
enum fuse_opcode expected;
|
|
|
1d442b |
@@ -2485,10 +2498,13 @@ void fuse_session_process_buf_int(struct fuse_session *se,
|
|
|
1d442b |
} else {
|
|
|
1d442b |
fuse_ll_ops[in->opcode].func(req, in->nodeid, &iter);
|
|
|
1d442b |
}
|
|
|
1d442b |
+
|
|
|
1d442b |
+ pthread_rwlock_unlock(&se->init_rwlock);
|
|
|
1d442b |
return;
|
|
|
1d442b |
|
|
|
1d442b |
reply_err:
|
|
|
1d442b |
fuse_reply_err(req, err);
|
|
|
1d442b |
+ pthread_rwlock_unlock(&se->init_rwlock);
|
|
|
1d442b |
}
|
|
|
1d442b |
|
|
|
1d442b |
#define LL_OPTION(n, o, v) \
|
|
|
1d442b |
@@ -2531,6 +2547,7 @@ void fuse_session_destroy(struct fuse_session *se)
|
|
|
1d442b |
se->op.destroy(se->userdata);
|
|
|
1d442b |
}
|
|
|
1d442b |
}
|
|
|
1d442b |
+ pthread_rwlock_destroy(&se->init_rwlock);
|
|
|
1d442b |
pthread_mutex_destroy(&se->lock);
|
|
|
1d442b |
free(se->cuse_data);
|
|
|
1d442b |
if (se->fd != -1) {
|
|
|
1d442b |
@@ -2610,6 +2627,7 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
|
|
|
1d442b |
list_init_req(&se->list);
|
|
|
1d442b |
list_init_req(&se->interrupts);
|
|
|
1d442b |
fuse_mutex_init(&se->lock);
|
|
|
1d442b |
+ pthread_rwlock_init(&se->init_rwlock, NULL);
|
|
|
1d442b |
|
|
|
1d442b |
memcpy(&se->op, op, op_size);
|
|
|
1d442b |
se->owner = getuid();
|