Re: Bug in getting file attributes with SMB3.1.1 and posix
From: Steve French
Date: Sun Feb 16 2025 - 23:27:00 EST
Oleh,
Good catch, and sorry about the delay (email had gotten missed).
Here is a fix (see attached) for the problem you reported. Let me
know if it also works for you or if you see any problems with it.
This is important fix for SMB3.1.1 POSIX Extensions client implementation.
On Wed, Jan 1, 2025 at 11:05 AM Oleh Nykyforchyn <oleh.nyk@xxxxxxxxx> wrote:
>
> Hello,
>
> I encountered a funny bug when a share is mounted with vers=3.1.1, posix,... If a file size has bits 0x410 = ATTR_DIRECTORY | ATTR_REPARSE = 1040 set, then the file is regarded as a directory and its open fails. A simplest test example is any file 1040 bytes long.
>
> The cause of this bug is that Attributes field in smb2_file_all_info struct occupies the same place that EndOfFile field in smb311_posix_qinfo, and sometimes the latter struct is incorrectly processed as if it was the first one. I attach an example patch that solves the problem for me, obviously not ready for submission, but just to show which places in the code are subject to problems. The patch is against linux-6.12.6 kernel, but, AFAICS, nothing has changed since then in relevant places. If I have guessed more or less correctly what the intended functionality is, please feel free to use my patch as a basis for corrections.
>
> Best regards
>
> Olen Nykyforchyn
--
Thanks,
Steve
From 540b0ebd176ad342644798947153aed35d5b9cab Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Sun, 16 Feb 2025 22:17:54 -0600
Subject: [PATCH] smb311: failure to open files of length 1040 when mounting
with SMB3.1.1 POSIX extensions
If a file size has bits 0x410 = ATTR_DIRECTORY | ATTR_REPARSE set
then during queryinfo (stat) the file is regarded as a directory
and subsequent opens can fail. A simple test example is trying
to open any file 1040 bytes long when mounting with "posix"
(SMB3.1.1 POSIX/Linux Extensions).
The cause of this bug is that Attributes field in smb2_file_all_info
struct occupies the same place that EndOfFile field in
smb311_posix_qinfo, and sometimes the latter struct is incorrectly
processed as if it was the first one.
Reported-by: Oleh Nykyforchyn <oleh.nyk@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/smb/client/cifsglob.h | 1 +
fs/smb/client/reparse.h | 28 ++++++++++++++++++++++------
fs/smb/client/smb2inode.c | 4 ++++
fs/smb/client/smb2ops.c | 3 ++-
4 files changed, 29 insertions(+), 7 deletions(-)
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index ac1f890a0d54..fcc5d95ed2cd 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -253,6 +253,7 @@ struct cifs_cred {
struct cifs_open_info_data {
bool adjust_tz;
bool reparse_point;
+ bool contains_posix_file_info;
struct {
/* ioctl response buffer */
struct {
diff --git a/fs/smb/client/reparse.h b/fs/smb/client/reparse.h
index 5a753fec7e2c..c0be5ab45a78 100644
--- a/fs/smb/client/reparse.h
+++ b/fs/smb/client/reparse.h
@@ -99,14 +99,30 @@ static inline bool reparse_inode_match(struct inode *inode,
static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
{
- struct smb2_file_all_info *fi = &data->fi;
- u32 attrs = le32_to_cpu(fi->Attributes);
+ u32 attrs;
bool ret;
- ret = data->reparse_point || (attrs & ATTR_REPARSE);
- if (ret)
- attrs |= ATTR_REPARSE;
- fi->Attributes = cpu_to_le32(attrs);
+ if (data->contains_posix_file_info) {
+ struct smb311_posix_qinfo *fi = &data->posix_fi;
+
+ attrs = le32_to_cpu(fi->DosAttributes);
+ if (data->reparse_point) {
+ attrs |= ATTR_REPARSE;
+ fi->DosAttributes = cpu_to_le32(attrs);
+ }
+
+ } else {
+ struct smb2_file_all_info *fi = &data->fi;
+
+ attrs = le32_to_cpu(fi->Attributes);
+ if (data->reparse_point) {
+ attrs |= ATTR_REPARSE;
+ fi->Attributes = cpu_to_le32(attrs);
+ }
+ }
+
+ ret = attrs & ATTR_REPARSE;
+
return ret;
}
diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 5dfb30b0a852..826b57a5a2a8 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -650,6 +650,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
switch (cmds[i]) {
case SMB2_OP_QUERY_INFO:
idata = in_iov[i].iov_base;
+ idata->contains_posix_file_info = false;
if (rc == 0 && cfile && cfile->symlink_target) {
idata->symlink_target = kstrdup(cfile->symlink_target, GFP_KERNEL);
if (!idata->symlink_target)
@@ -673,6 +674,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
break;
case SMB2_OP_POSIX_QUERY_INFO:
idata = in_iov[i].iov_base;
+ idata->contains_posix_file_info = true;
if (rc == 0 && cfile && cfile->symlink_target) {
idata->symlink_target = kstrdup(cfile->symlink_target, GFP_KERNEL);
if (!idata->symlink_target)
@@ -770,6 +772,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
idata = in_iov[i].iov_base;
idata->reparse.io.iov = *iov;
idata->reparse.io.buftype = resp_buftype[i + 1];
+ idata->contains_posix_file_info = false; /* BB VERIFY */
rbuf = reparse_buf_ptr(iov);
if (IS_ERR(rbuf)) {
rc = PTR_ERR(rbuf);
@@ -791,6 +794,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
case SMB2_OP_QUERY_WSL_EA:
if (!rc) {
idata = in_iov[i].iov_base;
+ idata->contains_posix_file_info = false;
qi_rsp = rsp_iov[i + 1].iov_base;
data[0] = (u8 *)qi_rsp + le16_to_cpu(qi_rsp->OutputBufferOffset);
size[0] = le32_to_cpu(qi_rsp->OutputBufferLength);
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index ec36bed54b0b..23e0c8be7fb5 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -1001,6 +1001,7 @@ static int smb2_query_file_info(const unsigned int xid, struct cifs_tcon *tcon,
if (!data->symlink_target)
return -ENOMEM;
}
+ data->contains_posix_file_info = false;
return SMB2_query_info(xid, tcon, fid->persistent_fid, fid->volatile_fid, &data->fi);
}
@@ -5146,7 +5147,7 @@ int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
FILE_CREATE, CREATE_NOT_DIR |
CREATE_OPTION_SPECIAL, ACL_NO_MODE);
oparms.fid = &fid;
-
+ idata.contains_posix_file_info = false;
rc = server->ops->open(xid, &oparms, &oplock, &idata);
if (rc)
goto out;
--
2.43.0