CVE-2023-52767

syzkaller discovered that if tlsswspliceeof() is executed as part of sendfile() when the plaintext/ciphertext skmsg are empty, the send path gets confused because the empty ciphertext buffer does not have enough space for the encryption overhead. This causes tlspushrecord() to go on the split = true path (which is only supposed to be used when interacting with an attached BPF program), and then get further confused and hit the tlsmergeopen_record() path, which then assumes that there must be at least one populated buffer element, leading to a NULL deref.

It is possible to have empty plaintext/ciphertext buffers if we previously bailed from tlsswsendmsglocked() via the tlstrimbothmsgs() path. tlsswpushpendingrecord() already handles this case correctly; let's do the same check in tlsswsplice_eof().

References

Affected packages

Debian:12 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

6.1.82-1

Affected versions

6.*

6.1.27-1

6.1.37-1

6.1.38-1

6.1.38-2~bpo11+1

6.1.38-2

6.1.38-3

6.1.38-4~bpo11+1

6.1.38-4

6.1.52-1

6.1.55-1~bpo11+1

6.1.55-1

6.1.64-1

6.1.66-1

6.1.67-1

6.1.69-1~bpo11+1

6.1.69-1

6.1.76-1~bpo11+1

6.1.76-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:13 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

6.6.8-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}