The name argument can never be an empty string, and dirfd always point to
the containing directory of the file name. AT_EMPTY_PATH is hence useless
here. Also it breaks build with glibc version 2.13 and older.

It is actually an oversight of a previous tentative patch to implement this
function. We can safely drop it.
Reported-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: NGreg Kurz <groug@kaod.org>
Tested-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit b314f6a0)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

If we cannot open the given path, we can return right away instead of
passing -1 to fstatfs() and close(). This will make Coverity happy.

(Coverity issue CID1371729)
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NDaniel P. berrange <berrange@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
(cherry picked from commit 23da0145)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

Coverity issue CID1371731
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
(cherry picked from commit faab207f)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

This was spotted by Coverity as a fd leak. This is certainly true, but also
local_remove() would always return without doing anything, unless the fd is
zero, which is very unlikely.

(Coverity issue CID1371732)
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit b7361d46)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

Now that the all callbacks have been converted to use "at" syscalls, we
can drop this code.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit c23d5f1d)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_open2() callback is vulnerable to symlink attacks because it
calls:

(1) open() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_open2() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively. Since local_open2() already opens
a descriptor to the target file, local_set_cred_passthrough() is
modified to reuse it instead of opening a new one.

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to openat().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit a565fea5)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_mkdir() callback is vulnerable to symlink attacks because it
calls:

(1) mkdir() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_mkdir() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively.

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mkdirat().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 3f3a1699)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_mknod() callback is vulnerable to symlink attacks because it
calls:

(1) mknod() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_mknod() to rely on opendir_nofollow() and
mknodat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.

A new local_set_cred_passthrough() helper based on fchownat() and
fchmodat_nofollow() is introduced as a replacement to
local_post_create_passthrough() to fix (4).

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mknodat().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit d815e721)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_symlink() callback is vulnerable to symlink attacks because it
calls:

(1) symlink() which follows symbolic links for all path elements but the
    rightmost one
(2) open(O_NOFOLLOW) which follows symbolic links for all path elements but
    the rightmost one
(3) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(4) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

This patch converts local_symlink() to rely on opendir_nofollow() and
symlinkat() to fix (1), openat(O_NOFOLLOW) to fix (2), as well as
local_set_xattrat() and local_set_mapped_file_attrat() to fix (3) and
(4) respectively.

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 38771613)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_chown() callback is vulnerable to symlink attacks because it
calls:

(1) lchown() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

This patch converts local_chown() to rely on open_nofollow() and
fchownat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit d369f207)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_chmod() callback is vulnerable to symlink attacks because it
calls:

(1) chmod() which follows symbolic links for all path elements
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

We would need fchmodat() to implement AT_SYMLINK_NOFOLLOW to fix (1). This
isn't the case on linux unfortunately: the kernel doesn't even have a flags
argument to the syscall :-\ It is impossible to fix it in userspace in
a race-free manner. This patch hence converts local_chmod() to rely on
open_nofollow() and fchmod(). This fixes the vulnerability but introduces
a limitation: the target file must readable and/or writable for the call
to openat() to succeed.

It introduces a local_set_xattrat() replacement to local_set_xattr()
based on fsetxattrat() to fix (2), and a local_set_mapped_file_attrat()
replacement to local_set_mapped_file_attr() based on local_fopenat()
and mkdirat() to fix (3). No effort is made to factor out code because
both local_set_xattr() and local_set_mapped_file_attr() will be dropped
when all users have been converted to use the "at" versions.

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit e3187a45)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_link() callback is vulnerable to symlink attacks because it calls:

(1) link() which follows symbolic links for all path elements but the
    rightmost one
(2) local_create_mapped_attr_dir()->mkdir() which follows symbolic links
    for all path elements but the rightmost one

This patch converts local_link() to rely on opendir_nofollow() and linkat()
to fix (1), mkdirat() to fix (2).

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit ad0b46e6)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

When using the mapped-file security model, we also have to create a link
for the metadata file if it exists. In case of failure, we should rollback.

That's what this patch does.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 6dd4b1f1)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_rename() callback is vulnerable to symlink attacks because it
uses rename() which follows symbolic links in all path elements but the
rightmost one.

This patch simply transforms local_rename() into a wrapper around
local_renameat() which is symlink-attack safe.

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit d2767ede)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_renameat() callback is currently a wrapper around local_rename()
which is vulnerable to symlink attacks.

This patch rewrites local_renameat() to have its own implementation, based
on local_opendir_nofollow() and renameat().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 99f2cf4b)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_lstat() callback is vulnerable to symlink attacks because it
calls:

(1) lstat() which follows symbolic links in all path elements but the
    rightmost one
(2) getxattr() which follows symbolic links in all path elements
(3) local_mapped_file_attr()->local_fopen()->openat(O_NOFOLLOW) which
    follows symbolic links in all path elements but the rightmost
    one

This patch converts local_lstat() to rely on opendir_nofollow() and
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1), fgetxattrat_nofollow() to
fix (2).

A new local_fopenat() helper is introduced as a replacement to
local_fopen() to fix (3). No effort is made to factor out code
because local_fopen() will be dropped when all users have been
converted to call local_fopenat().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit f9aef99b)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_readlink() callback is vulnerable to symlink attacks because it
calls:

(1) open(O_NOFOLLOW) which follows symbolic links for all path elements but
    the rightmost one
(2) readlink() which follows symbolic links for all path elements but the
    rightmost one

This patch converts local_readlink() to rely on open_nofollow() to fix (1)
and opendir_nofollow(), readlinkat() to fix (2).

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit bec1e954)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_truncate() callback is vulnerable to symlink attacks because
it calls truncate() which follows symbolic links in all path elements.

This patch converts local_truncate() to rely on open_nofollow() and
ftruncate() instead.

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit ac125d99)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_statfs() callback is vulnerable to symlink attacks because it
calls statfs() which follows symbolic links in all path elements.

This patch converts local_statfs() to rely on open_nofollow() and fstatfs()
instead.

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 31e51d1c)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_utimensat() callback is vulnerable to symlink attacks because it
calls qemu_utimens()->utimensat(AT_SYMLINK_NOFOLLOW) which follows symbolic
links in all path elements but the rightmost one or qemu_utimens()->utimes()
which follows symbolic links for all path elements.

This patch converts local_utimensat() to rely on opendir_nofollow() and
utimensat(AT_SYMLINK_NOFOLLOW) directly instead of using qemu_utimens().
It is hence assumed that the OS supports utimensat(), i.e. has glibc 2.6
or higher and linux 2.6.22 or higher, which seems reasonable nowadays.

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit a33eda0d)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_remove() callback is vulnerable to symlink attacks because it
calls:

(1) lstat() which follows symbolic links in all path elements but the
    rightmost one
(2) remove() which follows symbolic links in all path elements but the
    rightmost one

This patch converts local_remove() to rely on opendir_nofollow(),
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1) and unlinkat() to fix (2).

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit a0e640a8)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_unlinkat() callback is vulnerable to symlink attacks because it
calls remove() which follows symbolic links in all path elements but the
rightmost one.

This patch converts local_unlinkat() to rely on opendir_nofollow() and
unlinkat() instead.

Most of the code is moved to a separate local_unlinkat_common() helper
which will be reused in a subsequent patch to fix the same issue in
local_remove().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit df4938a6)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_lremovexattr() callback is vulnerable to symlink attacks because
it calls lremovexattr() which follows symbolic links in all path elements
but the rightmost one.

This patch introduces a helper to emulate the non-existing fremovexattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lremovexattr().

local_lremovexattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 72f0d0bf)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_lsetxattr() callback is vulnerable to symlink attacks because
it calls lsetxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing fsetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lsetxattr().

local_lsetxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 3e36aba7)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_llistxattr() callback is vulnerable to symlink attacks because
it calls llistxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing flistxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to llistxattr().

local_llistxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 5507904e)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_lgetxattr() callback is vulnerable to symlink attacks because
it calls lgetxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing fgetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lgetxattr().

local_lgetxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 56ad3e54)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

The local_open() and local_opendir() callbacks are vulnerable to symlink
attacks because they call:

(1) open(O_NOFOLLOW) which follows symbolic links in all path elements but
    the rightmost one
(2) opendir() which follows symbolic links in all path elements

This patch converts both callbacks to use new helpers based on
openat_nofollow() to only open files and directories if they are
below the virtfs shared folder

This partly fixes CVE-2016-9602.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 996a0d76)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

This patch opens the shared folder and caches the file descriptor, so that
it can be used to do symlink-safe path walk.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 0e35a378)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

When using the passthrough security mode, symbolic links created by the
guest are actual symbolic links on the host file system.

Since the resolution of symbolic links during path walk is supposed to
occur on the client side. The server should hence never receive any path
pointing to an actual symbolic link. This isn't guaranteed by the protocol
though, and malicious code in the guest can trick the server to issue
various syscalls on paths whose one or more elements are symbolic links.
In the case of the "local" backend using the "passthrough" or "none"
security modes, the guest can directly create symbolic links to arbitrary
locations on the host (as per spec). The "mapped-xattr" and "mapped-file"
security modes are also affected to a lesser extent as they require some
help from an external entity to create actual symbolic links on the host,
i.e. another guest using "passthrough" mode for example.

The current code hence relies on O_NOFOLLOW and "l*()" variants of system
calls. Unfortunately, this only applies to the rightmost path component.
A guest could maliciously replace any component in a trusted path with a
symbolic link. This could allow any guest to escape a virtfs shared folder.

This patch introduces a variant of the openat() syscall that successively
opens each path element with O_NOFOLLOW. When passing a file descriptor
pointing to a trusted directory, one is guaranteed to be returned a
file descriptor pointing to a path which is beneath the trusted directory.
This will be used by subsequent patches to implement symlink-safe path walk
for any access to the backend.

Symbolic links aren't the only threats actually: a malicious guest could
change a path element to point to other types of file with undesirable
effects:
- a named pipe or any other thing that would cause openat() to block
- a terminal device which would become QEMU's controlling terminal

These issues can be addressed with O_NONBLOCK and O_NOCTTY.

Two helpers are introduced: one to open intermediate path elements and one
to open the rightmost path element.
Suggested-by: NJann Horn <jannh@google.com>
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(renamed openat_nofollow() to relative_openat_nofollow(),
 assert path is relative and doesn't contain '//',
 fixed side-effect in assert, Greg Kurz)
Signed-off-by: NGreg Kurz <groug@kaod.org>

(cherry picked from commit 6482a961)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

If these functions fail, they should not change *fs. Let's use local
variables to fix this.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 21328e1e)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

If this function fails, it should not modify *ctx.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 00c90bd1)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

These functions are always called indirectly. It really doesn't make sense
for them to sit in a header file.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 56fc494b)
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

In the init operation of proxy backend dirver, it allocates a
V9fsProxy struct and some other resources. We should free these
resources when the 9pfs device is unrealized. This is what this
patch does.
Signed-off-by: NLi Qiang <liq3ea@gmail.com>
Reviewed-by: NGreg Kurz <groug@kaod.org>
Signed-off-by: NGreg Kurz <groug@kaod.org>

In the init operation of handle backend dirver, it allocates a
handle_data struct and opens a mount file. We should free these
resources when the 9pfs device is unrealized. This is what this
patch does.
Signed-off-by: NLi Qiang <liq3ea@gmail.com>
Reviewed-by: NGreg Kurz <groug@kaod.org>
Signed-off-by: NGreg Kurz <groug@kaod.org>

Currently, the backend of VirtFS doesn't have a cleanup
function. This will lead resource leak issues if the backed
driver allocates resources. This patch addresses this issue.
Signed-off-by: NLi Qiang <liq3ea@gmail.com>
Reviewed-by: NGreg Kurz <groug@kaod.org>
Signed-off-by: NGreg Kurz <groug@kaod.org>

Unrealize should undo things that were set during realize in
reverse order. So should do in the error path in realize.
Signed-off-by: NLi Qiang <liq3ea@gmail.com>
Reviewed-by: NGreg Kurz <groug@kaod.org>
Signed-off-by: NGreg Kurz <groug@kaod.org>

The virtfs_reset() function is called either when the virtio-9p device
gets reset, or when the client starts a new 9P session. In both cases,
if it finds fids from a previous session, the following is printed in
the monitor:

9pfs:virtfs_reset: One or more uncluncked fids found during reset

For example, if a linux guest with a mounted 9P share is reset from the
monitor with system_reset, the message will be printed. This is excessive
since these fids are now clunked and the state is clean.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NEric Blake <eblake@redhat.com>

A buggy or malicious guest could pass the id of an already opened fid and
cause QEMU to abort. Let's return EINVAL to the guest instead.
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NEric Blake <eblake@redhat.com>

The xattrcreate operation only makes sense on a freshly cloned fid
actually, since any open state would be leaked because of the fid_type
change. This is indeed what the linux kernel client does:

	fid = clone_fid(fid);
	[...]
	retval = p9_client_xattrcreate(fid, name, value_len, flags);

This patch also reverts commit ff55e94d since we are sure that a fid
with type P9_FID_NONE doesn't have a previously allocated xattr.
Signed-off-by: NGreg Kurz <groug@kaod.org>

We shouldn't allow guests to create extended attribute with arbitrary sizes.
On linux hosts, the limit is XATTR_SIZE_MAX. Let's use it.
Signed-off-by: NGreg Kurz <groug@kaod.org>