[Virtio-fs] [PATCH v5 5/9] virtiofsd, fuse_lowlevel.c: Add capability to parse security context
Dr. David Alan Gilbert
dgilbert at redhat.com
Thu Feb 3 19:41:27 UTC 2022
* Vivek Goyal (vgoyal at redhat.com) wrote:
> Add capability to enable and parse security context as sent by client
> and put into fuse_req. Filesystems now can get security context from
> request and set it on files during creation.
>
> Signed-off-by: Vivek Goyal <vgoyal at redhat.com>
> ---
> tools/virtiofsd/fuse_common.h | 5 ++
> tools/virtiofsd/fuse_i.h | 7 +++
> tools/virtiofsd/fuse_lowlevel.c | 95 ++++++++++++++++++++++++++++++++-
> 3 files changed, 106 insertions(+), 1 deletion(-)
>
> diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h
> index 6f8a988202..bf46954dab 100644
> --- a/tools/virtiofsd/fuse_common.h
> +++ b/tools/virtiofsd/fuse_common.h
> @@ -377,6 +377,11 @@ struct fuse_file_info {
> */
> #define FUSE_CAP_SETXATTR_EXT (1 << 29)
>
> +/**
> + * Indicates that file server supports creating file security context
> + */
> +#define FUSE_CAP_SECURITY_CTX (1ULL << 32)
> +
> /**
> * Ioctl flags
> *
> diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
> index 492e002181..a5572fa4ae 100644
> --- a/tools/virtiofsd/fuse_i.h
> +++ b/tools/virtiofsd/fuse_i.h
> @@ -15,6 +15,12 @@
> struct fv_VuDev;
> struct fv_QueueInfo;
>
> +struct fuse_security_context {
> + const char *name;
> + uint32_t ctxlen;
> + const void *ctx;
> +};
> +
> struct fuse_req {
> struct fuse_session *se;
> uint64_t unique;
> @@ -35,6 +41,7 @@ struct fuse_req {
> } u;
> struct fuse_req *next;
> struct fuse_req *prev;
> + struct fuse_security_context secctx;
> };
>
> struct fuse_notify_req {
> diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
> index 83d29762a4..cd9ef97b3c 100644
> --- a/tools/virtiofsd/fuse_lowlevel.c
> +++ b/tools/virtiofsd/fuse_lowlevel.c
> @@ -886,11 +886,59 @@ static void do_readlink(fuse_req_t req, fuse_ino_t nodeid,
> }
> }
>
> +static int parse_secctx_fill_req(fuse_req_t req, struct fuse_mbuf_iter *iter)
> +{
> + struct fuse_secctx_header *fsecctx_header;
> + struct fuse_secctx *fsecctx;
> + const void *secctx;
> + const char *name;
> +
> + fsecctx_header = fuse_mbuf_iter_advance(iter, sizeof(*fsecctx_header));
> + if (!fsecctx_header) {
> + return -EINVAL;
> + }
> +
> + /*
> + * As of now maximum of one security context is supported. It can
> + * change in future though.
> + */
> + if (fsecctx_header->nr_secctx > 1) {
> + return -EINVAL;
> + }
> +
> + /* No security context sent. Maybe no LSM supports it */
> + if (!fsecctx_header->nr_secctx) {
> + return 0;
> + }
> +
> + fsecctx = fuse_mbuf_iter_advance(iter, sizeof(*fsecctx));
> + if (!fsecctx) {
> + return -EINVAL;
> + }
Are there any sanity checks to be done on fsecctx->size?
> + name = fuse_mbuf_iter_advance_str(iter);
> + if (!name) {
> + return -EINVAL;
> + }
> +
> + secctx = fuse_mbuf_iter_advance(iter, fsecctx->size);
> + if (!secctx) {
> + return -EINVAL;
> + }
> +
> + req->secctx.name = name;
> + req->secctx.ctx = secctx;
> + req->secctx.ctxlen = fsecctx->size;
It's OK to use the pointers into the iter here rather than take copies?
> + return 0;
> +}
> +
> static void do_mknod(fuse_req_t req, fuse_ino_t nodeid,
> struct fuse_mbuf_iter *iter)
> {
> struct fuse_mknod_in *arg;
> const char *name;
> + bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
> + int err;
>
> arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
> name = fuse_mbuf_iter_advance_str(iter);
> @@ -901,6 +949,13 @@ static void do_mknod(fuse_req_t req, fuse_ino_t nodeid,
>
> req->ctx.umask = arg->umask;
>
> + if (secctx_enabled) {
> + err = parse_secctx_fill_req(req, iter);
> + if (err) {
> + fuse_reply_err(req, -err);
return ?
> + }
> + }
> +
> if (req->se->op.mknod) {
> req->se->op.mknod(req, nodeid, name, arg->mode, arg->rdev);
> } else {
> @@ -913,6 +968,8 @@ static void do_mkdir(fuse_req_t req, fuse_ino_t nodeid,
> {
> struct fuse_mkdir_in *arg;
> const char *name;
> + bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
> + int err;
>
> arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
> name = fuse_mbuf_iter_advance_str(iter);
> @@ -923,6 +980,13 @@ static void do_mkdir(fuse_req_t req, fuse_ino_t nodeid,
>
> req->ctx.umask = arg->umask;
>
> + if (secctx_enabled) {
> + err = parse_secctx_fill_req(req, iter);
> + if (err) {
> + fuse_reply_err(req, err);
return ?
> + }
> + }
> +
> if (req->se->op.mkdir) {
> req->se->op.mkdir(req, nodeid, name, arg->mode);
> } else {
> @@ -969,12 +1033,21 @@ static void do_symlink(fuse_req_t req, fuse_ino_t nodeid,
> {
> const char *name = fuse_mbuf_iter_advance_str(iter);
> const char *linkname = fuse_mbuf_iter_advance_str(iter);
> + bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
> + int err;
>
> if (!name || !linkname) {
> fuse_reply_err(req, EINVAL);
> return;
> }
>
> + if (secctx_enabled) {
> + err = parse_secctx_fill_req(req, iter);
> + if (err) {
> + fuse_reply_err(req, err);
return ?
> + }
> + }
> +
> if (req->se->op.symlink) {
> req->se->op.symlink(req, linkname, nodeid, name);
> } else {
> @@ -1048,6 +1121,8 @@ static void do_link(fuse_req_t req, fuse_ino_t nodeid,
> static void do_create(fuse_req_t req, fuse_ino_t nodeid,
> struct fuse_mbuf_iter *iter)
> {
> + bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
> +
> if (req->se->op.create) {
> struct fuse_create_in *arg;
> struct fuse_file_info fi;
> @@ -1060,6 +1135,15 @@ static void do_create(fuse_req_t req, fuse_ino_t nodeid,
> return;
> }
>
> + if (secctx_enabled) {
> + int err;
> + err = parse_secctx_fill_req(req, iter);
> + if (err) {
> + fuse_reply_err(req, err);
> + return;
> + }
> + }
> +
> memset(&fi, 0, sizeof(fi));
> fi.flags = arg->flags;
> fi.kill_priv = arg->open_flags & FUSE_OPEN_KILL_SUIDGID;
> @@ -2016,6 +2100,9 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid,
> if (flags & FUSE_SETXATTR_EXT) {
> se->conn.capable |= FUSE_CAP_SETXATTR_EXT;
> }
> + if (flags & FUSE_SECURITY_CTX) {
> + se->conn.capable |= FUSE_CAP_SECURITY_CTX;
> + }
> #ifdef HAVE_SPLICE
> #ifdef HAVE_VMSPLICE
> se->conn.capable |= FUSE_CAP_SPLICE_WRITE | FUSE_CAP_SPLICE_MOVE;
> @@ -2155,8 +2242,14 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid,
> outarg.flags |= FUSE_SETXATTR_EXT;
> }
>
> + if (se->conn.want & FUSE_CAP_SECURITY_CTX) {
> + /* bits 32..63 get shifted down 32 bits into the flags2 field */
> + outarg.flags2 |= FUSE_SECURITY_CTX >> 32;
> + }
> +
> fuse_log(FUSE_LOG_DEBUG, " INIT: %u.%u\n", outarg.major, outarg.minor);
> - fuse_log(FUSE_LOG_DEBUG, " flags=0x%08x\n", outarg.flags);
> + fuse_log(FUSE_LOG_DEBUG, " flags2=0x%08x flags=0x%08x\n", outarg.flags2,
> + outarg.flags);
> fuse_log(FUSE_LOG_DEBUG, " max_readahead=0x%08x\n", outarg.max_readahead);
> fuse_log(FUSE_LOG_DEBUG, " max_write=0x%08x\n", outarg.max_write);
> fuse_log(FUSE_LOG_DEBUG, " max_background=%i\n", outarg.max_background);
> --
> 2.34.1
>
--
Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK
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