CVE-2024-56593
Description
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.
How to fix
- linux linux_kernel5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.66, 6.12.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | v < 5.4.287, 5.5 ≤ v < 5.10.231, 5.11 ≤ v < 5.15.174, 5.16 ≤ v < 6.1.120, 6.2 ≤ v < 6.6.66, 6.7 ≤ v < 6.12.5 | 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.66, 6.12.5 |
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