msnfs41client: Patches for QueryVolumeInformation-should-return-STATUS_BUFFER_OVERFLOW, increase EA size, 2025-07-18
Posted by Anonymous on Fri 18th Jul 2025 13:22
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From dc5279b2ab6b75265921b901c8bfe116bddff084 Mon Sep 17 00:00:00 2001
From: Roland Mainz <roland.mainz@nrubsig.org>
Date: Fri, 18 Jul 2025 12:07:44 +0200
Subject: [PATCH 1/2] sys: VolumeInformation queries should return
 |STATUS_BUFFER_OVERFLOW|+partial data if buffer is too small

VolumeInformation queries should return |STATUS_BUFFER_OVERFLOW|+partial
data if buffer is too small, as required by the Win32 spec.

Previously we tried |STATUS_BUFFER_TOO_SMALL| and return the required
buffer size (so that the caller can allocate a bigger buffer and then
try again), but this caused the Visual Studio 2019 linker and
$ '/cygdrive/c/Program Files/Git/cmd/git' clone ... # to fail.

Reported-by: Cedric Blancher <cedric.blancher@gmail.com>
Signed-off-by: Cedric Blancher <cedric.blancher@gmail.com>
---
 sys/nfs41sys_driver.h     |  3 ++-
 sys/nfs41sys_fileinfo.c   |  2 +-
 sys/nfs41sys_updowncall.c | 20 +++++++++++++++-----
 sys/nfs41sys_volinfo.c    | 12 ++++++++----
 4 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/sys/nfs41sys_driver.h b/sys/nfs41sys_driver.h
index 3057e25..a5cb6cd 100644
--- a/sys/nfs41sys_driver.h
+++ b/sys/nfs41sys_driver.h
@@ -827,7 +827,8 @@ void unmarshal_nfs41_attrget(
     nfs41_updowncall_entry *cur,
     PVOID attr_value,
     ULONG *attr_len,
-    unsigned char **buf);
+    unsigned char **buf,
+    BOOL copy_partial);
 NTSTATUS nfs41_UpcallCreate(
     IN DWORD opcode,
     IN PSECURITY_CLIENT_CONTEXT clnt_sec_ctx,
diff --git a/sys/nfs41sys_fileinfo.c b/sys/nfs41sys_fileinfo.c
index 36407f6..202e2fd 100644
--- a/sys/nfs41sys_fileinfo.c
+++ b/sys/nfs41sys_fileinfo.c
@@ -156,7 +156,7 @@ void unmarshal_nfs41_getattr(
     nfs41_updowncall_entry *cur,
     unsigned char **buf)
 {
-    unmarshal_nfs41_attrget(cur, cur->buf, &cur->buf_len, buf);
+    unmarshal_nfs41_attrget(cur, cur->buf, &cur->buf_len, buf, FALSE);
     RtlCopyMemory(&cur->ChangeTime, *buf, sizeof(ULONGLONG));
 #ifdef DEBUG_MARSHAL_DETAIL
     if (cur->u.QueryFile.InfoClass == FileBasicInformation)
diff --git a/sys/nfs41sys_updowncall.c b/sys/nfs41sys_updowncall.c
index 9ec5382..7e113be 100644
--- a/sys/nfs41sys_updowncall.c
+++ b/sys/nfs41sys_updowncall.c
@@ -166,14 +166,24 @@ void unmarshal_nfs41_attrget(
     nfs41_updowncall_entry *cur,
     PVOID attr_value,
     ULONG *attr_len,
-    unsigned char **buf)
+    unsigned char **buf,
+    BOOL copy_partial)
 {
     ULONG buf_len;
     RtlCopyMemory(&buf_len, *buf, sizeof(ULONG));
-    if (buf_len > *attr_len) {
-        cur->status = STATUS_BUFFER_TOO_SMALL;
-        return;
+    if (copy_partial) {
+        if (buf_len > *attr_len) {
+            cur->status = STATUS_BUFFER_OVERFLOW;
+            buf_len = *attr_len;
+        }
     }
+    else {
+        if (buf_len > *attr_len) {
+            cur->status = STATUS_BUFFER_TOO_SMALL;
+            return;
+        }
+    }
+
     *buf += sizeof(ULONG);
     *attr_len = buf_len;
     RtlCopyMemory(attr_value, *buf, buf_len);
@@ -745,7 +755,7 @@ NTSTATUS nfs41_downcall(
             unmarshal_nfs41_symlink(cur, &buf);
             break;
         case NFS41_SYSOP_VOLUME_QUERY:
-            unmarshal_nfs41_attrget(cur, cur->buf, &cur->buf_len, &buf);
+            unmarshal_nfs41_attrget(cur, cur->buf, &cur->buf_len, &buf, TRUE);
             break;
         case NFS41_SYSOP_ACL_QUERY:
             status = unmarshal_nfs41_getacl(cur, &buf);
diff --git a/sys/nfs41sys_volinfo.c b/sys/nfs41sys_volinfo.c
index 1b1e470..182efcc 100644
--- a/sys/nfs41sys_volinfo.c
+++ b/sys/nfs41sys_volinfo.c
@@ -203,10 +203,14 @@ NTSTATUS nfs41_QueryVolumeInformation(
         goto out;
     }

-    if (entry->status == STATUS_BUFFER_TOO_SMALL) {
-        RxContext->InformationToReturn = entry->buf_len;
-        status = STATUS_BUFFER_TOO_SMALL;
-    } else if (entry->status == STATUS_SUCCESS) {
+    if (entry->status == STATUS_BUFFER_OVERFLOW) {
+        /*
+         * Supplied buffer was too small, so we copied only part of
+         * the data into the buffer
+         */
+        status = STATUS_BUFFER_OVERFLOW;
+    }
+    else if (entry->status == STATUS_SUCCESS) {
 #ifdef ENABLE_TIMINGS
         InterlockedIncrement(&volume.sops);
         InterlockedAdd64(&volume.size, entry->u.Volume.buf_len);
--
2.45.1

From d4de60c0ec48238977a8491c12b9cf64daf9b66a Mon Sep 17 00:00:00 2001
From: Roland Mainz <roland.mainz@nrubsig.org>
Date: Fri, 18 Jul 2025 13:58:16 +0200
Subject: [PATCH 2/2] daemon: Increase size limit for EAs to 8192

Increase size limit for EAs from 2048 to 8192.

Signed-off-by: Cedric Blancher <cedric.blancher@gmail.com>
---
 daemon/ea.c          | 8 ++++++++
 daemon/nfs41_const.h | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/daemon/ea.c b/daemon/ea.c
index b9e68b7..a1fb42f 100644
--- a/daemon/ea.c
+++ b/daemon/ea.c
@@ -32,6 +32,14 @@
 #include "daemon_debug.h"
 #include "nfs_ea.h"

+/*
+ * Compile safeguard to see whether |NFS4_EASIZE+header| will still fit into
+ * |UPCALL_BUF_SIZE|
+ */
+#if (NFS4_EASIZE+1024) > UPCALL_BUF_SIZE
+#error NFS4_EASIZE does not fit into UPCALL_BUF_SIZE
+#endif
+
 /*
  * |WIN_NFS4_EA_NAME_PREFIX| - Prefix for Windows EA in NFSv4
  * XATTR (extended attributes) namespace
diff --git a/daemon/nfs41_const.h b/daemon/nfs41_const.h
index 524dd30..9ce6692 100644
--- a/daemon/nfs41_const.h
+++ b/daemon/nfs41_const.h
@@ -42,7 +42,7 @@
 #define NFS4_OPAQUE_LIMIT_ATTR  (8192)
 #define NFS4_SESSIONID_SIZE     16
 #define NFS4_STATEID_OTHER      12
-#define NFS4_EASIZE             2048
+#define NFS4_EASIZE             8192
 #define NFS4_EANAME_SIZE        128

 #define NFSD_THREAD_STACK_SIZE (4*1024*1024)
--
2.45.1