net/tls: Consume empty data records in tls_sw_read_sock()
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.6.145, 6.12.97, 6.18.40, 7.1.5
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
In the Linux kernel, the following vulnerability has been resolved: net/tls: Consume empty data records in tls_sw_read_sock() A peer may send a zero-length TLS application_data record; TLS 1.3 explicitly permits these as a traffic-analysis countermeasure (RFC 8446, Section 5.1). After decryption such a record has full_len == 0. tls_sw_read_sock() hands it to the read_actor, which has no payload to consume and returns zero. The loop treats a zero return as backpressure (used <= 0), requeues the skb at the head of rx_list, and stops. rx_list is serviced head-first on the next call, so the empty record is dequeued, fails the same way, and is requeued again; every later record on the connection is blocked behind it. tls_sw_recvmsg() does not stall on this: a zero-length data record copies nothing and falls through to consume_skb(). Mirror that in the read_sock() path by recognizing an empty data record before the actor runs, consuming it, and continuing.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
From 662fbcec32f4af6bdcf5b4006b792ebe9543d945 · fixed in 0867b0f2513ebc1c475af9898c97f4772a68d964; From 662fbcec32f4af6bdcf5b4006b792ebe9543d945 · fixed in c6b440cf766a557b08d25f1b571b3d57d039686e; From 662fbcec32f4af6bdcf5b4006b792ebe9543d945 · fixed in e8a4c9fc437b16aef38f86ce3275677e36924259; From 662fbcec32f4af6bdcf5b4006b792ebe9543d945 · fixed in ebc295ce343600c2d60c1e1e0c5d192080217457; From 662fbcec32f4af6bdcf5b4006b792ebe9543d945 · fixed in 3be28e2c9cd0230cb51fd4967df095273afd3848
- Linux Linux
6.6
- KernelLinux
From 6.6.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.97; From 6.13.0 · fixed in 6.18.40; From 6.19.0 · fixed in 7.1.5