CVE-2024-56593: wifi: brcmfmac: Fix oops due to NULL pointer dereference in brcmf_sdiod_sglist_rw()
First published: Fri Dec 27 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: Fix oops due to NULL pointer dereference in brcmf_sdiod_sglist_rw() This patch fixes a NULL pointer dereference bug in brcmfmac that occurs when a high 'sd_sgentry_align' value applies (e.g. 512) and a lot of queued SKBs are sent from the pkt queue. The problem is the number of entries in the pre-allocated sgtable, it is nents = max(rxglom_size, txglom_size) + max(rxglom_size, txglom_size) >> 4 + 1. Given the default [rt]xglom_size=32 it's actually 35 which is too small. Worst case, the pkt queue can end up with 64 SKBs. This occurs when a new SKB is added for each original SKB if tailroom isn't enough to hold tail_pad. At least one sg entry is needed for each SKB. So, eventually the "skb_queue_walk loop" in brcmf_sdiod_sglist_rw may run out of sg entries. This makes sg_next return NULL and this causes the oops. The patch sets nents to max(rxglom_size, txglom_size) * 2 to be able handle the worst-case. Btw. this requires only 64-35=29 * 16 (or 20 if CONFIG_NEED_SG_DMA_LENGTH) = 464 additional bytes of memory.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | <5.4.287 | |
| Linux Kernel | >=5.5<5.10.231 | |
| Linux Kernel | >=5.11<5.15.174 | |
| Linux Kernel | >=5.16<6.1.120 | |
| Linux Kernel | >=6.2<6.6.66 | |
| Linux Kernel | >=6.7<6.12.5 | |
| debian/linux | <=5.10.223-1 | 5.10.234-1 6.1.129-1 6.1.128-1 6.12.21-1 |
| debian/linux-6.1 | 6.1.129-1~deb11u1 |
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Reference Links
- https://git.kernel.org/stable/c/342f87d263462c2670b77ea9a32074cab2ac6fa1
- https://git.kernel.org/stable/c/7522d7d745d13fbeff3350fe6aa56c8dae263571
- https://git.kernel.org/stable/c/dfb3f9d3f602602de208da7bdcc0f6d5ee74af68
- https://git.kernel.org/stable/c/67a25ea28f8ec1da8894f2f115d01d3becf67dc7
- https://git.kernel.org/stable/c/07c020c6d14d29e5a3ea4e4576b8ecf956a80834
- https://git.kernel.org/stable/c/34941321b516bd7c6103bd01287d71a1804d19d3
- https://git.kernel.org/stable/c/857282b819cbaa0675aaab1e7542e2c0579f52d7
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-56593
- https://nvd.nist.gov/vuln/detail/CVE-2024-56593
- https://launchpad.net/bugs/cve/CVE-2024-56593
- https://security-tracker.debian.org/tracker/CVE-2024-56593
- https://ubuntu.com/security/CVE-2024-56593
- https://git.kernel.org/linus/857282b819cbaa0675aaab1e7542e2c0579f52d7
Frequently Asked Questions
What is the severity of CVE-2024-56593?
CVE-2024-56593 is categorized as a moderate severity issue due to the potential for a NULL pointer dereference in the Linux kernel's brcmfmac component.
How do I fix CVE-2024-56593?
To fix CVE-2024-56593, you should upgrade your Linux kernel to a version that includes the patch addressing this vulnerability.
What affected versions are vulnerable to CVE-2024-56593?
CVE-2024-56593 affects Linux kernel versions prior to 5.4.287, between 5.5 and 5.10.231, between 5.11 and 5.15.174, between 5.16 and 6.1.120, between 6.2 and 6.6.66, and between 6.7 and 6.12.5.
What component of the Linux kernel is affected by CVE-2024-56593?
The vulnerability CVE-2024-56593 specifically affects the brcmfmac component of the Linux kernel.
When was CVE-2024-56593 disclosed?
CVE-2024-56593 was disclosed as part of a series of patches meant to address various issues in the Linux kernel.
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