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bh=V2BlothwnuvK74svt80ryMiDyNHZ1Slm0mwafWJ7S6I=; b=B2ErH+6cpsdKhist1n7EI0vAcC76YXligd8U8qJOtnQsLYK8LDbF1/XDR1TxjnmhhJG4sx YaBxCLUxmitq74BpYbmlDtwcbkIIuTmOhzp1sOCH4Vhqrm3wom5rvjcYG+CnCzjr6my2XZ 2sSAJOZeojSePMMt9C9+wtQlycLhEN4= X-MC-Unique: 7Lp1PuXEOA-VV9kUlbp93A-1 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, vgoyal@redhat.com, stefanha@redhat.com, groug@kaod.org 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 Message-Id: <20210428110100.27757-27-dgilbert@redhat.com> In-Reply-To: <20210428110100.27757-1-dgilbert@redhat.com> References: <20210428110100.27757-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.22, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" From: Vivek Goyal 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 --- 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_of= f, const struct fuse_buf *src, size_t src_of= f, - size_t len) + size_t len, bool dropped_cap_fsetid) { int src_is_fd =3D src->flags & FUSE_BUF_IS_FD; int dst_is_fd =3D 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 =3D src->flags & FUSE_BUF_PHYS_ADDR; =20 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) } =20 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 =3D 0, i; =20 @@ -309,7 +310,8 @@ ssize_t fuse_buf_copy(fuse_req_t req, struct fuse_bufve= c *dstv, dst_len =3D dst->size - dstv->off; len =3D min_size(src_len, dst_len); =20 - res =3D fuse_buf_copy_one(req, dst, dstv->off, src, srcv->off, len= ); + res =3D 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 han= ded + * over to a different thread/process, CAP_FSETID needs to be dropp= ed + * 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); =20 /** * Memory buffer iterator diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowleve= l.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, Vhos= tUserFSSlaveMsg *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 han= ded + * 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); =20 #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, Vhost= UserFSSlaveMsg *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_fse= tid) { VhostUserFSSlaveMsg *msg =3D g_malloc0(sizeof(VhostUserFSSlaveMsg) + sizeof(VhostUserFSSlaveMsgEntry)); @@ -1311,6 +1311,9 @@ ssize_t fuse_virtio_write(fuse_req_t req, const struc= t fuse_buf *dst, msg->entries[0].c_offset =3D (uintptr_t)src->mem + src_off; msg->entries[0].len =3D len; msg->entries[0].flags =3D VHOST_USER_FS_FLAG_MAP_W; + if (dropped_cap_fsetid) { + msg->flags |=3D VHOST_USER_FS_GENFLAG_DROP_FSETID; + } =20 int64_t result =3D fuse_virtio_io(req->se, msg, dst->fd); fuse_log(FUSE_LOG_DEBUG, "%s: result=3D%" PRId64 " \n", __func__, resu= lt); 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 i= no, } } =20 - res =3D fuse_buf_copy(req, &out_buf, in_buf); + res =3D fuse_buf_copy(req, &out_buf, in_buf, fi->kill_priv); if (res < 0) { fuse_reply_err(req, -res); } else { --=20 2.31.1