vulnerability

Red Hat: CVE-2024-36016: kernel: tty: n_gsm: fix possible out-of-bounds in gsm0_receive() (Multiple Advisories)

Severity
6
CVSS
(AV:A/AC:H/Au:M/C:C/I:C/A:C)
Published
05/29/2024
Added
07/16/2024
Modified
03/10/2025

Description

In the Linux kernel, the following vulnerability has been resolved:

tty: n_gsm: fix possible out-of-bounds in gsm0_receive()

Assuming the following:
- side A configures the n_gsm in basic option mode
- side B sends the header of a basic option mode frame with data length 1
- side A switches to advanced option mode
- side B sends 2 data bytes which exceeds gsm->len
Reason: gsm->len is not used in advanced option mode.
- side A switches to basic option mode
- side B keeps sending until gsm0_receive() writes past gsm->buf
Reason: Neither gsm->state nor gsm->len have been reset after
reconfiguration.

Fix this by changing gsm->count to gsm->len comparison from equal to less
than. Also add upper limit checks against the constant MAX_MRU in
gsm0_receive() and gsm1_receive() to harden against memory corruption of
gsm->len and gsm->mru.

All other checks remain as we still need to limit the data according to the
user configuration and actual payload size.

Solution(s)

redhat-upgrade-kernelredhat-upgrade-kernel-rt
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