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[Qemu-devel] [PATCH 2/4] 9pfs: check for file device to avoid QID path c
From: |
antonios.motakis |
Subject: |
[Qemu-devel] [PATCH 2/4] 9pfs: check for file device to avoid QID path collisions |
Date: |
Thu, 8 Feb 2018 19:00:17 +0100 |
From: Antonios Motakis <address@hidden>
The QID path should uniquely identify a file. However, the
inode of a file is currently used as the QID path, which
on its own only uniquely identifies wiles within a device.
Here we track the device hosting the 9pfs share, in order
to prevent security issues with QID path collisions from
other devices.
Signed-off-by: Antonios Motakis <address@hidden>
---
hw/9pfs/9p.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++-------------
hw/9pfs/9p.h | 1 +
2 files changed, 54 insertions(+), 14 deletions(-)
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 85a1ed8..4da858f 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -573,10 +573,16 @@ static void coroutine_fn virtfs_reset(V9fsPDU *pdu)
P9_STAT_MODE_SOCKET)
/* This is the algorithm from ufs in spfs */
-static void stat_to_qid(const struct stat *stbuf, V9fsQID *qidp)
+static int stat_to_qid(V9fsPDU *pdu, const struct stat *stbuf, V9fsQID *qidp)
{
size_t size;
+ if (pdu->s->dev_id == 0) {
+ pdu->s->dev_id = stbuf->st_dev;
+ } else if (pdu->s->dev_id != stbuf->st_dev) {
+ return -ENOSYS;
+ }
+
memset(&qidp->path, 0, sizeof(qidp->path));
size = MIN(sizeof(stbuf->st_ino), sizeof(qidp->path));
memcpy(&qidp->path, &stbuf->st_ino, size);
@@ -588,6 +594,8 @@ static void stat_to_qid(const struct stat *stbuf, V9fsQID
*qidp)
if (S_ISLNK(stbuf->st_mode)) {
qidp->type |= P9_QID_TYPE_SYMLINK;
}
+
+ return 0;
}
static int coroutine_fn fid_to_qid(V9fsPDU *pdu, V9fsFidState *fidp,
@@ -600,7 +608,10 @@ static int coroutine_fn fid_to_qid(V9fsPDU *pdu,
V9fsFidState *fidp,
if (err < 0) {
return err;
}
- stat_to_qid(&stbuf, qidp);
+ err = stat_to_qid(pdu, &stbuf, qidp);
+ if (err < 0) {
+ return err;
+ }
return 0;
}
@@ -831,7 +842,10 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu,
V9fsPath *path,
memset(v9stat, 0, sizeof(*v9stat));
- stat_to_qid(stbuf, &v9stat->qid);
+ err = stat_to_qid(pdu, stbuf, &v9stat->qid);
+ if (err < 0) {
+ return err;
+ }
v9stat->mode = stat_to_v9mode(stbuf);
v9stat->atime = stbuf->st_atime;
v9stat->mtime = stbuf->st_mtime;
@@ -892,7 +906,7 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu,
V9fsPath *path,
#define P9_STATS_ALL 0x00003fffULL /* Mask for All fields above */
-static void stat_to_v9stat_dotl(V9fsState *s, const struct stat *stbuf,
+static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf,
V9fsStatDotl *v9lstat)
{
memset(v9lstat, 0, sizeof(*v9lstat));
@@ -914,7 +928,7 @@ static void stat_to_v9stat_dotl(V9fsState *s, const struct
stat *stbuf,
/* Currently we only support BASIC fields in stat */
v9lstat->st_result_mask = P9_STATS_BASIC;
- stat_to_qid(stbuf, &v9lstat->qid);
+ return stat_to_qid(pdu, stbuf, &v9lstat->qid);
}
static void print_sg(struct iovec *sg, int cnt)
@@ -1116,7 +1130,6 @@ static void coroutine_fn v9fs_getattr(void *opaque)
uint64_t request_mask;
V9fsStatDotl v9stat_dotl;
V9fsPDU *pdu = opaque;
- V9fsState *s = pdu->s;
retval = pdu_unmarshal(pdu, offset, "dq", &fid, &request_mask);
if (retval < 0) {
@@ -1137,7 +1150,10 @@ static void coroutine_fn v9fs_getattr(void *opaque)
if (retval < 0) {
goto out;
}
- stat_to_v9stat_dotl(s, &stbuf, &v9stat_dotl);
+ retval = stat_to_v9stat_dotl(pdu, &stbuf, &v9stat_dotl);
+ if (retval < 0) {
+ goto out;
+ }
/* fill st_gen if requested and supported by underlying fs */
if (request_mask & P9_STATS_GEN) {
@@ -1377,7 +1393,10 @@ static void coroutine_fn v9fs_walk(void *opaque)
if (err < 0) {
goto out;
}
- stat_to_qid(&stbuf, &qid);
+ err = stat_to_qid(pdu, &stbuf, &qid);
+ if (err < 0) {
+ goto out;
+ }
v9fs_path_copy(&dpath, &path);
}
memcpy(&qids[name_idx], &qid, sizeof(qid));
@@ -1477,7 +1496,10 @@ static void coroutine_fn v9fs_open(void *opaque)
if (err < 0) {
goto out;
}
- stat_to_qid(&stbuf, &qid);
+ err = stat_to_qid(pdu, &stbuf, &qid);
+ if (err < 0) {
+ goto out;
+ }
if (S_ISDIR(stbuf.st_mode)) {
err = v9fs_co_opendir(pdu, fidp);
if (err < 0) {
@@ -1587,7 +1609,10 @@ static void coroutine_fn v9fs_lcreate(void *opaque)
fidp->flags |= FID_NON_RECLAIMABLE;
}
iounit = get_iounit(pdu, &fidp->path);
- stat_to_qid(&stbuf, &qid);
+ err = stat_to_qid(pdu, &stbuf, &qid);
+ if (err < 0) {
+ goto out;
+ }
err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
if (err < 0) {
goto out;
@@ -2308,7 +2333,10 @@ static void coroutine_fn v9fs_create(void *opaque)
}
}
iounit = get_iounit(pdu, &fidp->path);
- stat_to_qid(&stbuf, &qid);
+ err = stat_to_qid(pdu, &stbuf, &qid);
+ if (err < 0) {
+ goto out;
+ }
err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
if (err < 0) {
goto out;
@@ -2365,7 +2393,10 @@ static void coroutine_fn v9fs_symlink(void *opaque)
if (err < 0) {
goto out;
}
- stat_to_qid(&stbuf, &qid);
+ err = stat_to_qid(pdu, &stbuf, &qid);
+ if (err < 0) {
+ goto out;
+ }
err = pdu_marshal(pdu, offset, "Q", &qid);
if (err < 0) {
goto out;
@@ -3033,7 +3064,10 @@ static void coroutine_fn v9fs_mknod(void *opaque)
if (err < 0) {
goto out;
}
- stat_to_qid(&stbuf, &qid);
+ err = stat_to_qid(pdu, &stbuf, &qid);
+ if (err < 0) {
+ goto out;
+ }
err = pdu_marshal(pdu, offset, "Q", &qid);
if (err < 0) {
goto out;
@@ -3191,7 +3225,10 @@ static void coroutine_fn v9fs_mkdir(void *opaque)
if (err < 0) {
goto out;
}
- stat_to_qid(&stbuf, &qid);
+ err = stat_to_qid(pdu, &stbuf, &qid);
+ if (err < 0) {
+ goto out;
+ }
err = pdu_marshal(pdu, offset, "Q", &qid);
if (err < 0) {
goto out;
@@ -3589,6 +3626,8 @@ int v9fs_device_realize_common(V9fsState *s, const
V9fsTransport *t,
goto out;
}
+ s->dev_id = 0;
+
s->ctx.fst = &fse->fst;
fsdev_throttle_init(s->ctx.fst);
diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index 5ced427..afb4ebd 100644
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -252,6 +252,7 @@ struct V9fsState
Error *migration_blocker;
V9fsConf fsconf;
V9fsQID root_qid;
+ dev_t dev_id;
};
/* 9p2000.L open flags */
--
1.8.3.1