Five smb3 client fixes, most also for stable

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Merge tag '6.8-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull smb client fixes from Steve French:
 "Five smb3 client fixes, most also for stable:

   - Two multichannel fixes (one to fix potential handle leak on retry)

   - Work around possible serious data corruption (due to change in
     folios in 6.3, for cases when non standard maximum write size
     negotiated)

   - Symlink creation fix

   - Multiuser automount fix"

* tag '6.8-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  smb: Fix regression in writes when non-standard maximum write size negotiated
  smb: client: handle path separator of created SMB symlinks
  smb: client: set correct id, uid and cruid for multiuser automounts
  cifs: update the same create_guid on replay
  cifs: fix underflow in parse_server_interfaces()

fs/smb/client/cached_dir.c

@@ -242,6 +242,7 @@ replay_again:
 		.desired_access =  FILE_READ_DATA | FILE_READ_ATTRIBUTES,
 		.disposition = FILE_OPEN,
 		.fid = pfid,
+		.replay = !!(retries),
 	};
 
 	rc = SMB2_open_init(tcon, server,

fs/smb/client/cifsglob.h

@@ -1378,6 +1378,7 @@ struct cifs_open_parms {
 	struct cifs_fid *fid;
 	umode_t mode;
 	bool reconnect:1;
+	bool replay:1; /* indicates that this open is for a replay */
 };
 
 struct cifs_fid {

fs/smb/client/connect.c

@@ -3444,8 +3444,18 @@ int cifs_mount_get_tcon(struct cifs_mount_ctx *mnt_ctx)
 	 * the user on mount
 	 */
 	if ((cifs_sb->ctx->wsize == 0) ||
-	    (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx)))
-		cifs_sb->ctx->wsize = server->ops->negotiate_wsize(tcon, ctx);
+	    (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx))) {
+		cifs_sb->ctx->wsize =
+			round_down(server->ops->negotiate_wsize(tcon, ctx), PAGE_SIZE);
+		/*
+		 * in the very unlikely event that the server sent a max write size under PAGE_SIZE,
+		 * (which would get rounded down to 0) then reset wsize to absolute minimum eg 4096
+		 */
+		if (cifs_sb->ctx->wsize == 0) {
+			cifs_sb->ctx->wsize = PAGE_SIZE;
+			cifs_dbg(VFS, "wsize too small, reset to minimum ie PAGE_SIZE, usually 4096\n");
+		}
+	}
 	if ((cifs_sb->ctx->rsize == 0) ||
 	    (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
 		cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);

fs/smb/client/fs_context.c

@@ -1111,6 +1111,17 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
 	case Opt_wsize:
 		ctx->wsize = result.uint_32;
 		ctx->got_wsize = true;
+		if (ctx->wsize % PAGE_SIZE != 0) {
+			ctx->wsize = round_down(ctx->wsize, PAGE_SIZE);
+			if (ctx->wsize == 0) {
+				ctx->wsize = PAGE_SIZE;
+				cifs_dbg(VFS, "wsize too small, reset to minimum %ld\n", PAGE_SIZE);
+			} else {
+				cifs_dbg(VFS,
+					 "wsize rounded down to %d to multiple of PAGE_SIZE %ld\n",
+					 ctx->wsize, PAGE_SIZE);
+			}
+		}
 		break;
 	case Opt_acregmax:
 		ctx->acregmax = HZ * result.uint_32;

fs/smb/client/namespace.c

@@ -168,6 +168,21 @@ static char *automount_fullpath(struct dentry *dentry, void *page)
 	return s;
 }
 
+static void fs_context_set_ids(struct smb3_fs_context *ctx)
+{
+	kuid_t uid = current_fsuid();
+	kgid_t gid = current_fsgid();
+
+	if (ctx->multiuser) {
+		if (!ctx->uid_specified)
+			ctx->linux_uid = uid;
+		if (!ctx->gid_specified)
+			ctx->linux_gid = gid;
+	}
+	if (!ctx->cruid_specified)
+		ctx->cred_uid = uid;
+}
+
 /*
  * Create a vfsmount that we can automount
  */
@@ -205,6 +220,7 @@ static struct vfsmount *cifs_do_automount(struct path *path)
 	tmp.leaf_fullpath = NULL;
 	tmp.UNC = tmp.prepath = NULL;
 	tmp.dfs_root_ses = NULL;
+	fs_context_set_ids(&tmp);
 
 	rc = smb3_fs_context_dup(ctx, &tmp);
 	if (rc) {

fs/smb/client/smb2ops.c

@@ -619,7 +619,7 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
 		goto out;
 	}
 
-	while (bytes_left >= sizeof(*p)) {
+	while (bytes_left >= (ssize_t)sizeof(*p)) {
 		memset(&tmp_iface, 0, sizeof(tmp_iface));
 		tmp_iface.speed = le64_to_cpu(p->LinkSpeed);
 		tmp_iface.rdma_capable = le32_to_cpu(p->Capability & RDMA_CAPABLE) ? 1 : 0;
@@ -1204,6 +1204,7 @@ replay_again:
 		.disposition = FILE_OPEN,
 		.create_options = cifs_create_options(cifs_sb, 0),
 		.fid = &fid,
+		.replay = !!(retries),
 	};
 
 	rc = SMB2_open_init(tcon, server,
@@ -1569,6 +1570,7 @@ replay_again:
 		.disposition = FILE_OPEN,
 		.create_options = cifs_create_options(cifs_sb, create_options),
 		.fid = &fid,
+		.replay = !!(retries),
 	};
 
 	if (qi.flags & PASSTHRU_FSCTL) {
@@ -2295,6 +2297,7 @@ replay_again:
 		.disposition = FILE_OPEN,
 		.create_options = cifs_create_options(cifs_sb, 0),
 		.fid = fid,
+		.replay = !!(retries),
 	};
 
 	rc = SMB2_open_init(tcon, server,
@@ -2681,6 +2684,7 @@ replay_again:
 		.disposition = FILE_OPEN,
 		.create_options = cifs_create_options(cifs_sb, 0),
 		.fid = &fid,
+		.replay = !!(retries),
 	};
 
 	rc = SMB2_open_init(tcon, server,
@@ -5213,7 +5217,7 @@ static int smb2_create_reparse_symlink(const unsigned int xid,
 	struct inode *new;
 	struct kvec iov;
 	__le16 *path;
-	char *sym;
+	char *sym, sep = CIFS_DIR_SEP(cifs_sb);
 	u16 len, plen;
 	int rc = 0;
 
@@ -5227,7 +5231,8 @@ static int smb2_create_reparse_symlink(const unsigned int xid,
 		.symlink_target = sym,
 	};
 
-	path = cifs_convert_path_to_utf16(symname, cifs_sb);
+	convert_delimiter(sym, sep);
+	path = cifs_convert_path_to_utf16(sym, cifs_sb);
 	if (!path) {
 		rc = -ENOMEM;
 		goto out;
@@ -5250,7 +5255,10 @@ static int smb2_create_reparse_symlink(const unsigned int xid,
 	buf->PrintNameLength = cpu_to_le16(plen);
 	memcpy(buf->PathBuffer, path, plen);
 	buf->Flags = cpu_to_le32(*symname != '/' ? SYMLINK_FLAG_RELATIVE : 0);
+	if (*sym != sep)
+		buf->Flags = cpu_to_le32(SYMLINK_FLAG_RELATIVE);
 
+	convert_delimiter(sym, '/');
 	iov.iov_base = buf;
 	iov.iov_len = len;
 	new = smb2_get_reparse_inode(&data, inode->i_sb, xid,

fs/smb/client/smb2pdu.c

@@ -2404,8 +2404,13 @@ create_durable_v2_buf(struct cifs_open_parms *oparms)
 	 */
 	buf->dcontext.Timeout = cpu_to_le32(oparms->tcon->handle_timeout);
 	buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
-	generate_random_uuid(buf->dcontext.CreateGuid);
-	memcpy(pfid->create_guid, buf->dcontext.CreateGuid, 16);
+
+	/* for replay, we should not overwrite the existing create guid */
+	if (!oparms->replay) {
+		generate_random_uuid(buf->dcontext.CreateGuid);
+		memcpy(pfid->create_guid, buf->dcontext.CreateGuid, 16);
+	} else
+		memcpy(buf->dcontext.CreateGuid, pfid->create_guid, 16);
 
 	/* SMB2_CREATE_DURABLE_HANDLE_REQUEST is "DH2Q" */
 	buf->Name[0] = 'D';
@@ -3142,6 +3147,7 @@ replay_again:
 	/* reinitialize for possible replay */
 	flags = 0;
 	server = cifs_pick_channel(ses);
+	oparms->replay = !!(retries);
 
 	cifs_dbg(FYI, "create/open\n");
 	if (!ses || !server)