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From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
To: qemu-devel@nongnu.org, vgoyal@redhat.com, stefanha@redhat.com,
	groug@kaod.org
Cc: virtio-fs@redhat.com
Subject: [PATCH v3 26/26] virtiofsd: Ask qemu to drop CAP_FSETID if client asked for it
Date: Wed, 28 Apr 2021 12:01:00 +0100	[thread overview]
Message-ID: <20210428110100.27757-27-dgilbert@redhat.com> (raw)
In-Reply-To: <20210428110100.27757-1-dgilbert@redhat.com>

From: Vivek Goyal <vgoyal@redhat.com>

If qemu guest asked to drop CAP_FSETID upon write, send that info
to qemu in SLAVE_FS_IO message so that qemu can drop capability
before WRITE. This is to make sure that any setuid bit is killed
on fd (if there is one set).

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 tools/virtiofsd/buffer.c         | 10 ++++++----
 tools/virtiofsd/fuse_common.h    |  6 +++++-
 tools/virtiofsd/fuse_lowlevel.h  |  6 +++++-
 tools/virtiofsd/fuse_virtio.c    |  5 ++++-
 tools/virtiofsd/passthrough_ll.c |  2 +-
 5 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/tools/virtiofsd/buffer.c b/tools/virtiofsd/buffer.c
index 8135d52d2a..b4cda7db9a 100644
--- a/tools/virtiofsd/buffer.c
+++ b/tools/virtiofsd/buffer.c
@@ -203,7 +203,7 @@ static ssize_t fuse_buf_fd_to_fd(const struct fuse_buf *dst, size_t dst_off,
 static ssize_t fuse_buf_copy_one(fuse_req_t req,
                                  const struct fuse_buf *dst, size_t dst_off,
                                  const struct fuse_buf *src, size_t src_off,
-                                 size_t len)
+                                 size_t len, bool dropped_cap_fsetid)
 {
     int src_is_fd = src->flags & FUSE_BUF_IS_FD;
     int dst_is_fd = dst->flags & FUSE_BUF_IS_FD;
@@ -211,7 +211,8 @@ static ssize_t fuse_buf_copy_one(fuse_req_t req,
     int dst_is_phys = src->flags & FUSE_BUF_PHYS_ADDR;
 
     if (src_is_phys && !src_is_fd && dst_is_fd) {
-        return fuse_virtio_write(req, dst, dst_off, src, src_off, len);
+        return fuse_virtio_write(req, dst, dst_off, src, src_off, len,
+                                 dropped_cap_fsetid);
     }
     assert(!src_is_phys && !dst_is_phys);
     if (!src_is_fd && !dst_is_fd) {
@@ -267,7 +268,7 @@ static int fuse_bufvec_advance(struct fuse_bufvec *bufv, size_t len)
 }
 
 ssize_t fuse_buf_copy(fuse_req_t req, struct fuse_bufvec *dstv,
-                      struct fuse_bufvec *srcv)
+                      struct fuse_bufvec *srcv, bool dropped_cap_fsetid)
 {
     size_t copied = 0, i;
 
@@ -309,7 +310,8 @@ ssize_t fuse_buf_copy(fuse_req_t req, struct fuse_bufvec *dstv,
         dst_len = dst->size - dstv->off;
         len = min_size(src_len, dst_len);
 
-        res = fuse_buf_copy_one(req, dst, dstv->off, src, srcv->off, len);
+        res = fuse_buf_copy_one(req, dst, dstv->off, src, srcv->off, len,
+                                dropped_cap_fsetid);
         if (res < 0) {
             if (!copied) {
                 return res;
diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h
index beed03aa93..8a75729be9 100644
--- a/tools/virtiofsd/fuse_common.h
+++ b/tools/virtiofsd/fuse_common.h
@@ -733,10 +733,14 @@ size_t fuse_buf_size(const struct fuse_bufvec *bufv);
  * @param req The request this copy is part of
  * @param dst destination buffer vector
  * @param src source buffer vector
+ * @param dropped_cap_fsetid Caller has dropped CAP_FSETID. If work is handed
+ *        over to a different thread/process, CAP_FSETID needs to be dropped
+ *        there as well.
  * @return actual number of bytes copied or -errno on error
  */
 ssize_t fuse_buf_copy(fuse_req_t req,
-                      struct fuse_bufvec *dst, struct fuse_bufvec *src);
+                      struct fuse_bufvec *dst, struct fuse_bufvec *src,
+                      bool dropped_cap_fsetid);
 
 /**
  * Memory buffer iterator
diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h
index 24e580aafe..dfd7e1525c 100644
--- a/tools/virtiofsd/fuse_lowlevel.h
+++ b/tools/virtiofsd/fuse_lowlevel.h
@@ -2030,9 +2030,13 @@ int64_t fuse_virtio_io(struct fuse_session *se, VhostUserFSSlaveMsg *msg,
  * @param src The source (memory) buffer
  * @param src_off The GPA
  * @param len Length in bytes
+ * @param dropped_cap_fsetid Caller dropped CAP_FSETID. If it is being handed
+ *        over to different thread/process, CAP_FSETID needs to be dropped
+ *        before write.
  */
 ssize_t fuse_virtio_write(fuse_req_t req, const struct fuse_buf *dst,
                           size_t dst_off, const struct fuse_buf *src,
-                          size_t src_off, size_t len);
+                          size_t src_off, size_t len,
+                          bool dropped_cap_fsetid);
 
 #endif /* FUSE_LOWLEVEL_H_ */
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index c6ea2bd2a1..9f3d38942a 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -1291,7 +1291,7 @@ int64_t fuse_virtio_io(struct fuse_session *se, VhostUserFSSlaveMsg *msg,
  */
 ssize_t fuse_virtio_write(fuse_req_t req, const struct fuse_buf *dst,
                           size_t dst_off, const struct fuse_buf *src,
-                          size_t src_off, size_t len)
+                          size_t src_off, size_t len, bool dropped_cap_fsetid)
 {
     VhostUserFSSlaveMsg *msg = g_malloc0(sizeof(VhostUserFSSlaveMsg) +
                                          sizeof(VhostUserFSSlaveMsgEntry));
@@ -1311,6 +1311,9 @@ ssize_t fuse_virtio_write(fuse_req_t req, const struct fuse_buf *dst,
     msg->entries[0].c_offset = (uintptr_t)src->mem + src_off;
     msg->entries[0].len = len;
     msg->entries[0].flags = VHOST_USER_FS_FLAG_MAP_W;
+    if (dropped_cap_fsetid) {
+        msg->flags |= VHOST_USER_FS_GENFLAG_DROP_FSETID;
+    }
 
     int64_t result = fuse_virtio_io(req->se, msg, dst->fd);
     fuse_log(FUSE_LOG_DEBUG, "%s: result=%" PRId64 " \n", __func__, result);
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index c5b8a1f5b1..b76d878509 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -2301,7 +2301,7 @@ static void lo_write_buf(fuse_req_t req, fuse_ino_t ino,
         }
     }
 
-    res = fuse_buf_copy(req, &out_buf, in_buf);
+    res = fuse_buf_copy(req, &out_buf, in_buf, fi->kill_priv);
     if (res < 0) {
         fuse_reply_err(req, -res);
     } else {
-- 
2.31.1



  parent reply	other threads:[~2021-04-28 11:23 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-28 11:00 [PATCH v3 00/26] virtiofs dax patches Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 01/26] virtiofs: Fixup printf args Dr. David Alan Gilbert (git)
2021-05-04 14:54   ` Stefan Hajnoczi
2021-05-05 11:06     ` Dr. David Alan Gilbert
2021-05-06 15:56   ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 02/26] virtiofsd: Don't assume header layout Dr. David Alan Gilbert (git)
2021-05-04 15:12   ` Stefan Hajnoczi
2021-05-06 15:56   ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 03/26] DAX: vhost-user: Rework slave return values Dr. David Alan Gilbert (git)
2021-05-04 15:23   ` Stefan Hajnoczi
2021-05-27 15:59     ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 04/26] DAX: libvhost-user: Route slave message payload Dr. David Alan Gilbert (git)
2021-05-04 15:26   ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 05/26] DAX: libvhost-user: Allow popping a queue element with bad pointers Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 06/26] DAX subprojects/libvhost-user: Add virtio-fs slave types Dr. David Alan Gilbert (git)
2021-04-29 15:48   ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 07/26] DAX: virtio: Add shared memory capability Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 08/26] DAX: virtio-fs: Add cache BAR Dr. David Alan Gilbert (git)
2021-05-05 12:12   ` Stefan Hajnoczi
2021-05-05 18:59     ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 09/26] DAX: virtio-fs: Add vhost-user slave commands for mapping Dr. David Alan Gilbert (git)
2021-05-05 14:15   ` Stefan Hajnoczi
2021-05-27 16:57     ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 10/26] DAX: virtio-fs: Fill in " Dr. David Alan Gilbert (git)
2021-05-05 16:43   ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 11/26] DAX: virtiofsd Add cache accessor functions Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 12/26] DAX: virtiofsd: Add setup/remove mappings fuse commands Dr. David Alan Gilbert (git)
2021-05-06 15:02   ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 13/26] DAX: virtiofsd: Add setup/remove mapping handlers to passthrough_ll Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 14/26] DAX: virtiofsd: Wire up passthrough_ll's lo_setupmapping Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 15/26] DAX: virtiofsd: Make lo_removemapping() work Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 16/26] DAX: virtiofsd: route se down to destroy method Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 17/26] DAX: virtiofsd: Perform an unmap on destroy Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 18/26] DAX/unmap: virtiofsd: Add VHOST_USER_SLAVE_FS_IO Dr. David Alan Gilbert (git)
2021-05-06 15:12   ` Stefan Hajnoczi
2021-05-27 17:44     ` Dr. David Alan Gilbert
2021-05-06 15:16   ` Stefan Hajnoczi
2021-05-27 17:31     ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 19/26] DAX/unmap virtiofsd: Add wrappers for VHOST_USER_SLAVE_FS_IO Dr. David Alan Gilbert (git)
2021-04-28 12:53   ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 20/26] DAX/unmap virtiofsd: Parse unmappable elements Dr. David Alan Gilbert (git)
2021-05-06 15:23   ` Stefan Hajnoczi
2021-05-27 17:56     ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 21/26] DAX/unmap virtiofsd: Route unmappable reads Dr. David Alan Gilbert (git)
2021-05-06 15:27   ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 22/26] DAX/unmap virtiofsd: route unmappable write to slave command Dr. David Alan Gilbert (git)
2021-05-06 15:28   ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 23/26] DAX:virtiofsd: implement FUSE_INIT map_alignment field Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 24/26] vhost-user-fs: Extend VhostUserFSSlaveMsg to pass additional info Dr. David Alan Gilbert (git)
2021-05-06 15:31   ` Stefan Hajnoczi
2021-05-06 15:32   ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 25/26] vhost-user-fs: Implement drop CAP_FSETID functionality Dr. David Alan Gilbert (git)
2021-04-28 11:01 ` Dr. David Alan Gilbert (git) [this message]
2021-05-06 15:37   ` [PATCH v3 26/26] virtiofsd: Ask qemu to drop CAP_FSETID if client asked for it Stefan Hajnoczi
2021-05-06 16:02     ` Vivek Goyal
2021-05-10  9:05       ` Stefan Hajnoczi
2021-05-10 15:23         ` Vivek Goyal
2021-05-10 15:32           ` Stefan Hajnoczi
2021-05-27 19:09             ` Dr. David Alan Gilbert
2021-06-10 15:29               ` Dr. David Alan Gilbert
2021-06-10 16:23                 ` Stefan Hajnoczi
2021-06-16 12:36                   ` Dr. David Alan Gilbert
2021-06-16 15:29                     ` Stefan Hajnoczi
2021-06-16 18:35                       ` Dr. David Alan Gilbert
2021-04-28 11:27 ` [PATCH v3 00/26] virtiofs dax patches no-reply
2021-05-06 15:37 ` Stefan Hajnoczi

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