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CVE-2024-56700: media: wl128x: Fix atomicity violation in fmc_send_cmd()

Description

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

media: wl128x: Fix atomicity violation in fmc_send_cmd()

Atomicity violation occurs when the fmc_send_cmd() function is executed
simultaneously with the modification of the fmdev->resp_skb value.
Consider a scenario where, after passing the validity check within the
function, a non-null fmdev->resp_skb variable is assigned a null value.
This results in an invalid fmdev->resp_skb variable passing the validity
check. As seen in the later part of the function, skb = fmdev->resp_skb;
when the invalid fmdev->resp_skb passes the check, a null pointer
dereference error may occur at line 478, evt_hdr = (void *)skb->data;

To address this issue, it is recommended to include the validity check of
fmdev->resp_skb within the locked section of the function. This
modification ensures that the value of fmdev->resp_skb does not change
during the validation process, thereby maintaining its validity.

This possible bug is found by an experimental static analysis tool
developed by our team. This tool analyzes the locking APIs
to extract function pairs that can be concurrently executed, and then
analyzes the instructions in the paired functions to identify possible
concurrency bugs including data races and atomicity violations.

Classification

CVE ID: CVE-2024-56700

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/d16109c9fdc1b8cea4fe63b42e06e926c3f68990
https://git.kernel.org/stable/c/3c818ad07e964bca3d27adac1e1f50e1e3c9180e
https://git.kernel.org/stable/c/d7408a052aa1b4f6fb6f1c7a8877b84017a07ac9
https://git.kernel.org/stable/c/ed228b74d8a500380150965d5becabf9a1e33141
https://git.kernel.org/stable/c/372dc9509122e5d45d4c12978e31c3c7d00aaca4
https://git.kernel.org/stable/c/378ce4e08ca2b1ac7bbf1d57b68643ca4226c5f8
https://git.kernel.org/stable/c/2e63c908de357048180516b84740ed62dac0b269
https://git.kernel.org/stable/c/80a3b2ee01eecf22dfa06968b3cde92c691dea10
https://git.kernel.org/stable/c/ca59f9956d4519ab18ab2270be47c6b8c6ced091

Timeline