Beyond Linux® From Scratch (System V Edition) - Version r11.2-1338

Chapter 20. Major Servers

vsftpd-3.0.5

Introduction to vsftpd

The vsftpd package contains a very secure and very small FTP daemon. This is useful for serving files over a network.

This package is known to build and work properly using an LFS 11.3 platform.

Package Information

vsftpd Dependencies

Required

libnsl-2.0.0

Recommended

Linux-PAM-1.5.2

Optional

libcap-2.67 with PAM

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/vsftpd

Installation of vsftpd

For security reasons, running vsftpd as an unprivileged user and group is encouraged. Also, a user should be created to map anonymous users. As the root user, create the needed directories, users, and groups with the following commands: 

install -v -d -m 0755 /usr/share/vsftpd/empty &&
install -v -d -m 0755 /home/ftp               &&
groupadd -g 47 vsftpd                         &&
groupadd -g 45 ftp                            &&

useradd -c "vsftpd User"  -d /dev/null -g vsftpd -s /bin/false -u 47 vsftpd &&
useradd -c anonymous_user -d /home/ftp -g ftp    -s /bin/false -u 45 ftp

Gcc-10 and later flags an error for an implicit type cast. Make it explicit: 

sed -e "s/kVSFSysStrOpenUnknown;/(enum EVSFSysUtilOpenMode)&/" -i sysstr.c

Build vsftpd as an unprivileged user using the following command: 

make

This package does not come with a test suite.

Once again, become the root user and install vsftpd with the following commands: 

install -v -m 755 vsftpd        /usr/sbin/vsftpd    &&
install -v -m 644 vsftpd.8      /usr/share/man/man8 &&
install -v -m 644 vsftpd.conf.5 /usr/share/man/man5 &&
install -v -m 644 vsftpd.conf   /etc

Command Explanations

install -v -d ...: This creates the directory that anonymous users will use (/home/ftp) and the directory the daemon will chroot into (/usr/share/vsftpd/empty).

[Note]

Note

/home/ftp should not be owned by the user vsftpd, or the user ftp.

echo "#define VSF_BUILD_TCPWRAPPERS" >>builddefs.h: Use this prior to make to add support for tcpwrappers.

echo "#define VSF_BUILD_SSL" >>builddefs.h: Use this prior to make to add support for SSL.

install -v -m ...: The Makefile uses non-standard installation paths. These commands install the files in /usr and /etc.

Configuring vsftpd

Config Files

/etc/vsftpd.conf

Configuration Information

vsftpd comes with a basic anonymous-only configuration file that was copied to /etc above. While still as root, this file should be modified because it is now recommended to run vsftpd in standalone mode. Also, you should specify the privilege separation user created above. Finally, you should specify the chroot directory. man vsftpd.conf will give you all the details. 

cat >> /etc/vsftpd.conf << "EOF"
background=YES
nopriv_user=vsftpd
secure_chroot_dir=/usr/share/vsftpd/empty
EOF

The vsftpd daemon uses seccomp to improve security by default. But it's known to cause vsftpd unable to handle ftp LIST command with recent kernel versions. Append a line to /etc/vsftpd.conf (as the root user) to disable seccomp and workaround this issue: 

cat >> /etc/vsftpd.conf << "EOF"
seccomp_sandbox=NO
EOF

To enable local logins, append the following to the /etc/vsftpd.conf file (as the root user): 

cat >> /etc/vsftpd.conf << "EOF"
local_enable=YES
EOF

In addition, if using Linux-PAM and vsftpd with local user logins, you will need a Linux-PAM configuration file. As the root user, create the /etc/pam.d/vsftpd file, and add the needed configuration changes for Linux-PAM session support using the following commands: 

cat > /etc/pam.d/vsftpd << "EOF" &&
# Begin /etc/pam.d/vsftpd
auth       required     /lib/security/pam_listfile.so item=user sense=deny \
                                                      file=/etc/ftpusers \
                                                      onerr=succeed
auth       required     pam_shells.so
auth       include      system-auth
account    include      system-account
session    include      system-session
EOF

cat >> /etc/vsftpd.conf << "EOF"
session_support=YES
pam_service_name=vsftpd
EOF

Boot Script

Install the /etc/rc.d/init.d/vsftpd init script included in the blfs-bootscripts-20230101 package: 

make install-vsftpd

Contents

Installed Program: vsftpd
Installed Libraries: None
Installed Directories: /usr/share/vsftpd, /home/ftp

Short Descriptions

vsftpd

is the FTP daemon