Moderate: samba security, bug fix, and enhancement update

Topic

An update for samba is now available for Red Hat Enterprise Linux 8.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

Samba is an open-source implementation of the Server Message Block (SMB) protocol and the related Common Internet File System (CIFS) protocol, which allow PC-compatible machines to share files, printers, and various information.

The following packages have been upgraded to a later upstream version: samba (4.15.5). (BZ#2013596)

Security Fix(es):

• samba: Symlink race error can allow metadata read and modify outside of the exported share (CVE-2021-20316)
• samba: Information leak via symlinks of existance of files or directories outside of the exported share (CVE-2021-44141)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.6 Release Notes linked from the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the smb service will be restarted automatically.

Affected Products

• Red Hat Enterprise Linux for x86_64 8 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 8.6 x86_64
• Red Hat Enterprise Linux Server - AUS 8.6 x86_64
• Red Hat Enterprise Linux for IBM z Systems 8 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 8.6 s390x
• Red Hat Enterprise Linux for Power, little endian 8 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 8.6 ppc64le
• Red Hat Virtualization Host 4 for RHEL 8 x86_64
• Red Hat Enterprise Linux Server - TUS 8.6 x86_64
• Red Hat Enterprise Linux for ARM 64 8 aarch64
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 8.6 aarch64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 8.6 ppc64le
• Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions 8.6 x86_64
• Red Hat CodeReady Linux Builder for x86_64 8 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian 8 ppc64le
• Red Hat CodeReady Linux Builder for ARM 64 8 aarch64
• Red Hat CodeReady Linux Builder for IBM z Systems 8 s390x
• Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support 8.6 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support 8.6 ppc64le
• Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support 8.6 s390x
• Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support 8.6 aarch64

Fixes

• BZ - 1979959 - Samba autorid fails to map AD users if id rangesize fits in the id range only once
• BZ - 1995849 - [RFE] Change change password change prompt phrasing
• BZ - 1999294 - With "samba-4.13.3-4.el8_4.x86_64" there was error/message in the winbind service status . "open_internal_pipe: Could not connect to dssetup pipe: NT_STATUS_RPC_INTERFACE_NOT_FOUND" ; "DCERPC_NCA_S_OP_RNG_ERROR "
• BZ - 2009673 - CVE-2021-20316 samba: Symlink race error can allow metadata read and modify outside of the exported share
• BZ - 2013596 - Rebase Samba to the the latest 4.15.x release
• BZ - 2019461 - Directory containing dangling symlinks cannot be deleted.
• BZ - 2028029 - Winbindd crashes after NULL pointer dereference - missing return value check in winbindd_util.c:fill_domain_username_talloc()
• BZ - 2035528 - [smb] Segmentation fault when joining the domain
• BZ - 2038148 - Failed to authenticate users after upgrade samba package to release samba-4.14.5-7x
• BZ - 2038796 - filename_convert_internal: open_pathref_fsp [xxx] failed: NT_STATUS_ACCESS_DENIED
• BZ - 2043154 - smb.service: Got notification message from PID [pid1], but reception only permitted for main PID [pid2]
• BZ - 2044404 - Printing no longer works on Windows 7 with 2021-10 monthly rollup patch (KB5006743)
• BZ - 2046120 - CVE-2021-44141 samba: Information leak via symlinks of existance of files or directories outside of the exported share
• BZ - 2049602 - SAMBA: Disable NTLMSSP for ldap client connections (e.g. libads)
• BZ - 2057503 - Regression: [samba] winbind isn't able to refresh Kerberos tickets
• BZ - 2064325 - [Regression] `create krb5 conf = yes` doesn't work with a single KDC

CVEs

• CVE-2021-20316
• CVE-2021-44141

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.6_release_notes/