aboutsummaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorGreg Kurz <groug@kaod.org>2021-06-24 12:18:09 +0200
committerDr. David Alan Gilbert <dgilbert@redhat.com>2021-07-05 10:51:26 +0100
commit1d03e5660711c40f79917054328e0dc6bcb879a3 (patch)
treeffb792629e4a5e975439029c120d3e2506bbce9b /include
parent3399bca4514b5c8d513a88fa3e472756468cb4c6 (diff)
virtiofsd: Don't allow file creation with FUSE_OPEN
A well behaved FUSE client uses FUSE_CREATE to create files. It isn't supposed to pass O_CREAT along a FUSE_OPEN request, as documented in the "fuse_lowlevel.h" header : /** * Open a file * * Open flags are available in fi->flags. The following rules * apply. * * - Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be * filtered out / handled by the kernel. But if the client happens to do it anyway, the server ends up passing this flag to open() without the mandatory mode_t 4th argument. Since open() is a variadic function, glibc will happily pass whatever it finds on the stack to the syscall. If this file is compiled with -D_FORTIFY_SOURCE=2, glibc will even detect that and abort: *** invalid openat64 call: O_CREAT or O_TMPFILE without mode ***: terminated Specifying O_CREAT with FUSE_OPEN is a protocol violation. Check this in do_open(), print out a message and return an error to the client, EINVAL like we already do when fuse_mbuf_iter_advance() fails. The FUSE filesystem doesn't currently support O_TMPFILE, but the very same would happen if O_TMPFILE was passed in a FUSE_OPEN request. Check that as well. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210624101809.48032-1-groug@kaod.org> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions