Commit fc22118d authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Anthony Liguori

virtio-9p: Use layered xattr approach

We would need this to make sure we handle the mapped
security model correctly for different xattr names.
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
parent 0f8151cb
......@@ -249,7 +249,8 @@ sound-obj-$(CONFIG_CS4231A) += cs4231a.o
adlib.o fmopl.o: QEMU_CFLAGS += -DBUILD_Y8950=0
hw-obj-$(CONFIG_SOUND) += $(sound-obj-y)
hw-obj-$(CONFIG_VIRTFS) += virtio-9p-debug.o virtio-9p-local.o
hw-obj-$(CONFIG_VIRTFS) += virtio-9p-debug.o virtio-9p-local.o virtio-9p-xattr.o
hw-obj-$(CONFIG_VIRTFS) += virtio-9p-xattr-user.o
######################################################################
# libdis
......
......@@ -47,11 +47,14 @@ typedef struct FsCred
dev_t fc_rdev;
} FsCred;
struct xattr_operations;
typedef struct FsContext
{
char *fs_root;
SecModel fs_sm;
uid_t uid;
struct xattr_operations **xops;
} FsContext;
extern void cred_init(FsCred *);
......@@ -94,4 +97,12 @@ typedef struct FileOperations
int (*lremovexattr)(FsContext *, const char *, const char *);
void *opaque;
} FileOperations;
static inline const char *rpath(FsContext *ctx, const char *path)
{
/* FIXME: so wrong... */
static char buffer[4096];
snprintf(buffer, sizeof(buffer), "%s/%s", ctx->fs_root, path);
return buffer;
}
#endif
......@@ -12,6 +12,7 @@
*/
#include "virtio.h"
#include "virtio-9p.h"
#include "virtio-9p-xattr.h"
#include <arpa/inet.h>
#include <pwd.h>
#include <grp.h>
......@@ -19,14 +20,6 @@
#include <sys/un.h>
#include <attr/xattr.h>
static const char *rpath(FsContext *ctx, const char *path)
{
/* FIXME: so wrong... */
static char buffer[4096];
snprintf(buffer, sizeof(buffer), "%s/%s", ctx->fs_root, path);
return buffer;
}
static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf)
{
......@@ -497,103 +490,25 @@ static int local_statfs(FsContext *s, const char *path, struct statfs *stbuf)
static ssize_t local_lgetxattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
if ((ctx->fs_sm == SM_MAPPED) &&
(strncmp(name, "user.virtfs.", 12) == 0)) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = ENOATTR;
return -1;
}
return lgetxattr(rpath(ctx, path), name, value, size);
return v9fs_get_xattr(ctx, path, name, value, size);
}
static ssize_t local_llistxattr(FsContext *ctx, const char *path,
void *value, size_t size)
{
ssize_t retval;
ssize_t actual_len = 0;
char *orig_value, *orig_value_start;
char *temp_value, *temp_value_start;
ssize_t xattr_len, parsed_len = 0, attr_len;
if (ctx->fs_sm != SM_MAPPED) {
return llistxattr(rpath(ctx, path), value, size);
}
/* Get the actual len */
xattr_len = llistxattr(rpath(ctx, path), value, 0);
/* Now fetch the xattr and find the actual size */
orig_value = qemu_malloc(xattr_len);
xattr_len = llistxattr(rpath(ctx, path), orig_value, xattr_len);
/*
* For mapped security model drop user.virtfs namespace
* from the list
*/
temp_value = qemu_mallocz(xattr_len);
temp_value_start = temp_value;
orig_value_start = orig_value;
while (xattr_len > parsed_len) {
attr_len = strlen(orig_value) + 1;
if (strncmp(orig_value, "user.virtfs.", 12) != 0) {
/* Copy this entry */
strcat(temp_value, orig_value);
temp_value += attr_len;
actual_len += attr_len;
}
parsed_len += attr_len;
orig_value += attr_len;
}
if (!size) {
retval = actual_len;
goto out;
} else if (size >= actual_len) {
/* now copy the parsed attribute list back */
memset(value, 0, size);
memcpy(value, temp_value_start, actual_len);
retval = actual_len;
goto out;
}
errno = ERANGE;
retval = -1;
out:
qemu_free(orig_value_start);
qemu_free(temp_value_start);
return retval;
return v9fs_list_xattr(ctx, path, value, size);
}
static int local_lsetxattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags)
{
if ((ctx->fs_sm == SM_MAPPED) &&
(strncmp(name, "user.virtfs.", 12) == 0)) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = EACCES;
return -1;
}
return lsetxattr(rpath(ctx, path), name, value, size, flags);
return v9fs_set_xattr(ctx, path, name, value, size, flags);
}
static int local_lremovexattr(FsContext *ctx,
const char *path, const char *name)
{
if ((ctx->fs_sm == SM_MAPPED) &&
(strncmp(name, "user.virtfs.", 12) == 0)) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = EACCES;
return -1;
}
return lremovexattr(rpath(ctx, path), name);
return v9fs_remove_xattr(ctx, path, name);
}
......
/*
* Virtio 9p user. xattr callback
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include <sys/types.h>
#include "virtio.h"
#include "virtio-9p.h"
#include "file-op-9p.h"
#include "virtio-9p-xattr.h"
static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = ENOATTR;
return -1;
}
return lgetxattr(rpath(ctx, path), name, value, size);
}
static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
char *name, void *value, size_t size)
{
int name_size = strlen(name) + 1;
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
return 0;
}
if (!value) {
return name_size;
}
if (size < name_size) {
errno = ERANGE;
return -1;
}
strncpy(value, name, name_size);
return name_size;
}
static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags)
{
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = EACCES;
return -1;
}
return lsetxattr(rpath(ctx, path), name, value, size, flags);
}
static int mp_user_removexattr(FsContext *ctx,
const char *path, const char *name)
{
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = EACCES;
return -1;
}
return lremovexattr(rpath(ctx, path), name);
}
XattrOperations mapped_user_xattr = {
.name = "user.",
.getxattr = mp_user_getxattr,
.setxattr = mp_user_setxattr,
.listxattr = mp_user_listxattr,
.removexattr = mp_user_removexattr,
};
XattrOperations passthrough_user_xattr = {
.name = "user.",
.getxattr = pt_getxattr,
.setxattr = pt_setxattr,
.listxattr = pt_listxattr,
.removexattr = pt_removexattr,
};
/*
* Virtio 9p xattr callback
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "virtio.h"
#include "virtio-9p.h"
#include "file-op-9p.h"
#include "virtio-9p-xattr.h"
static XattrOperations *get_xattr_operations(XattrOperations **h,
const char *name)
{
XattrOperations *xops;
for (xops = *(h)++; xops != NULL; xops = *(h)++) {
if (!strncmp(name, xops->name, strlen(xops->name))) {
return xops;
}
}
return NULL;
}
ssize_t v9fs_get_xattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
XattrOperations *xops = get_xattr_operations(ctx->xops, name);
if (xops) {
return xops->getxattr(ctx, path, name, value, size);
}
errno = -EOPNOTSUPP;
return -1;
}
ssize_t pt_listxattr(FsContext *ctx, const char *path,
char *name, void *value, size_t size)
{
int name_size = strlen(name) + 1;
if (!value) {
return name_size;
}
if (size < name_size) {
errno = ERANGE;
return -1;
}
strncpy(value, name, name_size);
return name_size;
}
/*
* Get the list and pass to each layer to find out whether
* to send the data or not
*/
ssize_t v9fs_list_xattr(FsContext *ctx, const char *path,
void *value, size_t vsize)
{
ssize_t size = 0;
void *ovalue = value;
XattrOperations *xops;
char *orig_value, *orig_value_start;
ssize_t xattr_len, parsed_len = 0, attr_len;
/* Get the actual len */
xattr_len = llistxattr(rpath(ctx, path), value, 0);
/* Now fetch the xattr and find the actual size */
orig_value = qemu_malloc(xattr_len);
xattr_len = llistxattr(rpath(ctx, path), orig_value, xattr_len);
/* store the orig pointer */
orig_value_start = orig_value;
while (xattr_len > parsed_len) {
xops = get_xattr_operations(ctx->xops, orig_value);
if (!xops) {
goto next_entry;
}
if (!value) {
size += xops->listxattr(ctx, path, orig_value, value, vsize);
} else {
size = xops->listxattr(ctx, path, orig_value, value, vsize);
if (size < 0) {
goto err_out;
}
value += size;
vsize -= size;
}
next_entry:
/* Got the next entry */
attr_len = strlen(orig_value) + 1;
parsed_len += attr_len;
orig_value += attr_len;
}
if (value) {
size = value - ovalue;
}
err_out:
qemu_free(orig_value_start);
return size;
}
int v9fs_set_xattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags)
{
XattrOperations *xops = get_xattr_operations(ctx->xops, name);
if (xops) {
return xops->setxattr(ctx, path, name, value, size, flags);
}
errno = -EOPNOTSUPP;
return -1;
}
int v9fs_remove_xattr(FsContext *ctx,
const char *path, const char *name)
{
XattrOperations *xops = get_xattr_operations(ctx->xops, name);
if (xops) {
return xops->removexattr(ctx, path, name);
}
errno = -EOPNOTSUPP;
return -1;
}
XattrOperations *mapped_xattr_ops[] = {
&mapped_user_xattr,
NULL,
};
XattrOperations *passthrough_xattr_ops[] = {
&passthrough_user_xattr,
NULL,
};
/* for .user none model should be same as passthrough */
XattrOperations *none_xattr_ops[] = {
&passthrough_user_xattr,
NULL,
};
/*
* Virtio 9p
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#ifndef _QEMU_VIRTIO_9P_XATTR_H
#define _QEMU_VIRTIO_9P_XATTR_H
#include <attr/xattr.h>
typedef struct xattr_operations
{
const char *name;
ssize_t (*getxattr)(FsContext *ctx, const char *path,
const char *name, void *value, size_t size);
ssize_t (*listxattr)(FsContext *ctx, const char *path,
char *name, void *value, size_t size);
int (*setxattr)(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags);
int (*removexattr)(FsContext *ctx,
const char *path, const char *name);
} XattrOperations;
extern XattrOperations mapped_user_xattr;
extern XattrOperations passthrough_user_xattr;
extern XattrOperations *mapped_xattr_ops[];
extern XattrOperations *passthrough_xattr_ops[];
extern XattrOperations *none_xattr_ops[];
extern ssize_t v9fs_get_xattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size);
extern ssize_t v9fs_list_xattr(FsContext *ctx, const char *path,
void *value, size_t vsize);
extern int v9fs_set_xattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags);
extern int v9fs_remove_xattr(FsContext *ctx,
const char *path, const char *name);
extern ssize_t pt_listxattr(FsContext *ctx, const char *path,
char *name, void *value, size_t size);
static inline ssize_t pt_getxattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
return lgetxattr(rpath(ctx, path), name, value, size);
}
static inline int pt_setxattr(FsContext *ctx, const char *path,
const char *name, void *value,
size_t size, int flags)
{
return lsetxattr(rpath(ctx, path), name, value, size, flags);
}
static inline int pt_removexattr(FsContext *ctx,
const char *path, const char *name)
{
return lremovexattr(rpath(ctx, path), name);
}
#endif
......@@ -17,6 +17,7 @@
#include "virtio-9p.h"
#include "fsdev/qemu-fsdev.h"
#include "virtio-9p-debug.h"
#include "virtio-9p-xattr.h"
int debug_9p_pdu;
......@@ -3712,23 +3713,26 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
if (!strcmp(fse->security_model, "passthrough")) {
/* Files on the Fileserver set to client user credentials */
s->ctx.fs_sm = SM_PASSTHROUGH;
s->ctx.xops = passthrough_xattr_ops;
} else if (!strcmp(fse->security_model, "mapped")) {
/* Files on the fileserver are set to QEMU credentials.
* Client user credentials are saved in extended attributes.
*/
s->ctx.fs_sm = SM_MAPPED;
s->ctx.xops = mapped_xattr_ops;
} else if (!strcmp(fse->security_model, "none")) {
/*
* Files on the fileserver are set to QEMU credentials.
*/
s->ctx.fs_sm = SM_NONE;
s->ctx.xops = none_xattr_ops;
} else {
fprintf(stderr, "Default to security_model=none. You may want"
" enable advanced security model using "
"security option:\n\t security_model=passthrough \n\t "
"security_model=mapped\n");
s->ctx.fs_sm = SM_NONE;
s->ctx.xops = none_xattr_ops;
}
if (lstat(fse->path, &stat)) {
......
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