[Qemu-devel] [PULL 7/7] 9p: xattr: Properly translate xattrcreate flags

[Greg Kurz <groug@kaod.org>]

From: Keno Fischer <keno@juliacomputing.com>

As with unlinkat, these flags come from the client and need to
be translated to their host values. The protocol values happen
to match linux, but that need not be true in general.

Signed-off-by: Keno Fischer <keno@juliacomputing.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/9pfs/9p.c | 17 +++++++++++++++--
 hw/9pfs/9p.h |  4 ++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index c842ec555ea1..eef289e394d4 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -3327,7 +3327,7 @@ out_nofid:
 
 static void coroutine_fn v9fs_xattrcreate(void *opaque)
 {
-    int flags;
+    int flags, rflags = 0;
     int32_t fid;
     uint64_t size;
     ssize_t err = 0;
@@ -3344,6 +3344,19 @@ static void coroutine_fn v9fs_xattrcreate(void *opaque)
     }
     trace_v9fs_xattrcreate(pdu->tag, pdu->id, fid, name.data, size, flags);
 
+    if (flags & ~(P9_XATTR_CREATE | P9_XATTR_REPLACE)) {
+        err = -EINVAL;
+        goto out_nofid;
+    }
+
+    if (flags & P9_XATTR_CREATE) {
+        rflags |= XATTR_CREATE;
+    }
+
+    if (flags & P9_XATTR_REPLACE) {
+        rflags |= XATTR_REPLACE;
+    }
+
     if (size > XATTR_SIZE_MAX) {
         err = -E2BIG;
         goto out_nofid;
@@ -3365,7 +3378,7 @@ static void coroutine_fn v9fs_xattrcreate(void *opaque)
     xattr_fidp->fs.xattr.copied_len = 0;
     xattr_fidp->fs.xattr.xattrwalk_fid = false;
     xattr_fidp->fs.xattr.len = size;
-    xattr_fidp->fs.xattr.flags = flags;
+    xattr_fidp->fs.xattr.flags = rflags;
     v9fs_string_init(&xattr_fidp->fs.xattr.name);
     v9fs_string_copy(&xattr_fidp->fs.xattr.name, &name);
     xattr_fidp->fs.xattr.value = g_malloc0(size);
diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index bad8ee719c4b..8883761b2c1d 100644
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -169,6 +169,10 @@ typedef struct V9fsConf
     char *fsdev_id;
 } V9fsConf;
 
+/* 9p2000.L xattr flags (matches Linux values) */
+#define P9_XATTR_CREATE 1
+#define P9_XATTR_REPLACE 2
+
 typedef struct V9fsXattr
 {
     uint64_t copied_len;
-- 
2.14.4