Add required infrastructure and modify create/open2 and mkdir per the new
security model.
Signed-off-by: Venkateswararao Jujjuri <jv...@linux.vnet.ibm.com>
---
hw/file-op-9p.h | 23 +++++++++-
hw/virtio-9p-local.c | 117 +++++++++++++++++++++++++++++++++----------------
hw/virtio-9p.c | 42 ++++++++++++------
3 files changed, 129 insertions(+), 53 deletions(-)
diff --git a/hw/file-op-9p.h b/hw/file-op-9p.h
index f84767f..1eceeb2 100644
--- a/hw/file-op-9p.h
+++ b/hw/file-op-9p.h
@@ -18,13 +18,32 @@
#include <utime.h>
#include <sys/stat.h>
#include <sys/uio.h>
+#define SM_LOCAL_MODE_BITS 0600
+
+typedef enum
+{
+ sm_none = 0,
+ sm_passthrough, /* uid/gid set on fileserver files */
+ sm_mapped, /* uid/gid part of xattr */
+} SecModel;
+
+typedef struct FsCred
+{
+ uid_t fc_uid;
+ gid_t fc_gid;
+ mode_t fc_mode;
+ dev_t fc_rdev;
+} FsCred;
typedef struct FsContext
{
char *fs_root;
+ SecModel fs_sm;
uid_t uid;
} FsContext;
+extern void cred_init(FsCred *);
+
typedef struct FileOperations
{
int (*lstat)(FsContext *, const char *, struct stat *);
@@ -42,7 +61,7 @@ typedef struct FileOperations
int (*closedir)(FsContext *, DIR *);
DIR *(*opendir)(FsContext *, const char *);
int (*open)(FsContext *, const char *, int);
- int (*open2)(FsContext *, const char *, int, mode_t);
+ int (*open2)(FsContext *, const char *, int, FsCred *);
void (*rewinddir)(FsContext *, DIR *);
off_t (*telldir)(FsContext *, DIR *);
struct dirent *(*readdir)(FsContext *, DIR *);
@@ -50,7 +69,7 @@ typedef struct FileOperations
ssize_t (*readv)(FsContext *, int, const struct iovec *, int);
ssize_t (*writev)(FsContext *, int, const struct iovec *, int);
off_t (*lseek)(FsContext *, int, off_t, int);
- int (*mkdir)(FsContext *, const char *, mode_t);
+ int (*mkdir)(FsContext *, const char *, FsCred *);
int (*fstat)(FsContext *, int, struct stat *);
int (*rename)(FsContext *, const char *, const char *);
int (*truncate)(FsContext *, const char *, off_t);
diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
index 1afb731..8ed8c66 100644
--- a/hw/virtio-9p-local.c
+++ b/hw/virtio-9p-local.c
@@ -17,6 +17,7 @@
#include <grp.h>
#include <sys/socket.h>
#include <sys/un.h>
+#include <attr/xattr.h>
static const char *rpath(FsContext *ctx, const char *path)
{
@@ -31,47 +32,49 @@ static int local_lstat(FsContext *ctx, const char *path,
struct stat *stbuf)
return lstat(rpath(ctx, path), stbuf);
}
-static int local_setuid(FsContext *ctx, uid_t uid)
+static void local_set_cred(FsCred *credp)
{
- struct passwd *pw;
- gid_t groups[33];
- int ngroups;
- static uid_t cur_uid = -1;
-
- if (cur_uid == uid) {
- return 0;
+ if (credp->fc_uid != -1) {
+ setuid(credp->fc_uid);
}
-
- if (setreuid(0, 0)) {
- return -1;
+ if (credp->fc_gid != -1) {
+ setgid(credp->fc_gid);
}
+}
- pw = getpwuid(uid);
- if (pw == NULL) {
- return -1;
+static int local_set_xattr(const char *path, FsCred *credp)
+{
+ int err;
+ if (credp->fc_uid != -1) {
+ err = setxattr(path, "user.virtfs.uid", &credp->fc_uid, sizeof(uid_t),
+ XATTR_CREATE);
+ if (err) {
+ return err;
+ }
}
-
- ngroups = 33;
- if (getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups) == -1) {
- return -1;
+ if (credp->fc_gid != -1) {
+ err = setxattr(path, "user.virtfs.gid", &credp->fc_uid, sizeof(gid_t),
+ XATTR_CREATE);
+ if (err) {
+ return err;
+ }
}
-
- if (setgroups(ngroups, groups)) {
- return -1;
+ if (credp->fc_mode != -1) {
+ err = setxattr(path, "user.virtfs.mode", &credp->fc_mode,
+ sizeof(mode_t), XATTR_CREATE);
+ if (err) {
+ return err;
+ }
}
-
- if (setregid(-1, pw->pw_gid)) {
- return -1;
- }
-
- if (setreuid(-1, uid)) {
- return -1;
+ if (credp->fc_rdev != -1) {
+ err = setxattr(path, "user.virtfs.rdev", &credp->fc_rdev,
+ sizeof(dev_t), XATTR_CREATE);
+ if (err) {
+ return err;
+ }
}
-
- cur_uid = uid;
-
- return 0;
-}
+ return 0;
+ }
static ssize_t local_readlink(FsContext *ctx, const char *path,
char *buf, size_t bufsz)
@@ -168,9 +171,26 @@ static int local_mksock(FsContext *ctx2, const char *path)
return 0;
}
-static int local_mkdir(FsContext *ctx, const char *path, mode_t mode)
+static int local_mkdir(FsContext *fs_ctx, const char *path, FsCred *credp)
{
- return mkdir(rpath(ctx, path), mode);
+ int err = -1;
+ /* Determine the security model */
+ if (fs_ctx->fs_sm == sm_mapped) {
+ err = mkdir(rpath(fs_ctx, path), SM_LOCAL_MODE_BITS);
+ if (err == -1) {
+ return err;
+ }
+ credp->fc_mode = credp->fc_mode|S_IFDIR;
+ err = local_set_xattr(rpath(fs_ctx, path), credp);
+ if (err == -1) {
+ remove(rpath(fs_ctx, path));
+ return err;
+ }
+ } else if (fs_ctx->fs_sm == sm_passthrough) {
+ local_set_cred(credp);
+ err = mkdir(rpath(fs_ctx, path), credp->fc_mode);
+ }
+ return err;
}
static int local_fstat(FsContext *ctx, int fd, struct stat *stbuf)
@@ -178,9 +198,31 @@ static int local_fstat(FsContext *ctx, int fd, struct stat
*stbuf)
return fstat(fd, stbuf);
}
-static int local_open2(FsContext *ctx, const char *path, int flags, mode_t
mode)
+static int local_open2(FsContext *fs_ctx, const char *path, int flags,
+ FsCred *credp)
{
- return open(rpath(ctx, path), flags, mode);
+ int fd = -1;
+ /* Determine the security model */
+ if (fs_ctx->fs_sm == sm_mapped) {
+ int err;
+ fd = open(rpath(fs_ctx, path), flags, SM_LOCAL_MODE_BITS);
+ if (fd == -1) {
+ goto err_end;
+ }
+ credp->fc_mode = credp->fc_mode|S_IFREG;
+ /* Set cleint credentials in xattr */
+ err = local_set_xattr(rpath(fs_ctx, path), credp);
+ if (err == -1) {
+ close(fd);
+ remove(rpath(fs_ctx, path));
+ return err;
+ }
+ } else if (fs_ctx->fs_sm == sm_passthrough) {
+ local_set_cred(credp);
+ fd = open(rpath(fs_ctx, path), flags, credp->fc_mode);
+ }
+err_end:
+ return fd;
}
static int local_symlink(FsContext *ctx, const char *oldpath,
@@ -264,7 +306,6 @@ static int local_fsync(FsContext *ctx, int fd)
FileOperations local_ops = {
.lstat = local_lstat,
- .setuid = local_setuid,
.readlink = local_readlink,
.close = local_close,
.closedir = local_closedir,
diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index 365259c..9033541 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -67,14 +67,17 @@ static int omode_to_uflags(int8_t mode)
return ret;
}
-static int v9fs_do_lstat(V9fsState *s, V9fsString *path, struct stat *stbuf)
+void cred_init(FsCred *credp)
{
- return s->ops->lstat(&s->ctx, path->data, stbuf);
+ credp->fc_uid = -1;
+ credp->fc_gid = -1;
+ credp->fc_mode = -1;
+ credp->fc_rdev = -1;
}
-static int v9fs_do_setuid(V9fsState *s, uid_t uid)
+static int v9fs_do_lstat(V9fsState *s, V9fsString *path, struct stat *stbuf)
{
- return s->ops->setuid(&s->ctx, uid);
+ return s->ops->lstat(&s->ctx, path->data, stbuf);
}
static ssize_t v9fs_do_readlink(V9fsState *s, V9fsString *path, V9fsString
*buf)
@@ -164,9 +167,15 @@ static int v9fs_do_mksock(V9fsState *s, V9fsString *path)
return s->ops->mksock(&s->ctx, path->data);
}
-static int v9fs_do_mkdir(V9fsState *s, V9fsString *path, mode_t mode)
+static int v9fs_do_mkdir(V9fsState *s, V9fsCreateState *vs)
{
- return s->ops->mkdir(&s->ctx, path->data, mode);
+ FsCred cred;
+
+ cred_init(&cred);
+ cred.fc_uid = vs->fidp->uid;
+ cred.fc_mode = vs->perm & 0777;
+
+ return s->ops->mkdir(&s->ctx, vs->fullname.data, &cred);
}
static int v9fs_do_fstat(V9fsState *s, int fd, struct stat *stbuf)
@@ -174,9 +183,17 @@ static int v9fs_do_fstat(V9fsState *s, int fd, struct stat
*stbuf)
return s->ops->fstat(&s->ctx, fd, stbuf);
}
-static int v9fs_do_open2(V9fsState *s, V9fsString *path, int flags, mode_t
mode)
+static int v9fs_do_open2(V9fsState *s, V9fsCreateState *vs)
{
- return s->ops->open2(&s->ctx, path->data, flags, mode);
+ FsCred cred;
+ int flags;
+
+ cred_init(&cred);
+ cred.fc_uid = vs->fidp->uid;
+ cred.fc_mode = vs->perm & 0777;
+ flags = omode_to_uflags(vs->mode) | O_CREAT;
+
+ return s->ops->open2(&s->ctx, vs->fullname.data, flags, &cred);
}
static int v9fs_do_symlink(V9fsState *s, V9fsString *oldpath,
@@ -348,7 +365,6 @@ static V9fsFidState *lookup_fid(V9fsState *s, int32_t fid)
for (f = s->fid_list; f; f = f->next) {
if (f->fid == fid) {
- v9fs_do_setuid(s, f->uid);
return f;
}
}
@@ -1758,7 +1774,7 @@ static void v9fs_create_post_lstat(V9fsState *s,
V9fsCreateState *vs, int err)
}
if (vs->perm & P9_STAT_MODE_DIR) {
- err = v9fs_do_mkdir(s, &vs->fullname, vs->perm & 0777);
+ err = v9fs_do_mkdir(s, vs);
v9fs_create_post_mkdir(s, vs, err);
} else if (vs->perm & P9_STAT_MODE_SYMLINK) {
err = v9fs_do_symlink(s, &vs->extension, &vs->fullname);
@@ -1805,9 +1821,7 @@ static void v9fs_create_post_lstat(V9fsState *s,
V9fsCreateState *vs, int err)
err = v9fs_do_mksock(s, &vs->fullname);
v9fs_create_post_mksock(s, vs, err);
} else {
- vs->fidp->fd = v9fs_do_open2(s, &vs->fullname,
- omode_to_uflags(vs->mode) | O_CREAT,
- vs->perm & 0777);
+ vs->fidp->fd = v9fs_do_open2(s, vs);
v9fs_create_post_open2(s, vs, err);
}
@@ -2255,10 +2269,12 @@ 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;
} 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;
} else {
/* user haven't specified a correct security option */
fprintf(stderr, "one of the following must be specified as the"
--
1.6.5.2
