CVE-2024-36016 Information

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.

Reference

https://git.kernel.org/stable/c/47388e807f85948eefc403a8a5fdc5b406a65d5a https://git.kernel.org/stable/c/f126ce7305fe88f49cdabc6db4168b9318898ea3 https://git.kernel.org/stable/c/b890d45aaf02b564e6cae2d2a590f9649330857d