CVE-2024-26896

Published Apr 17, 2024

Last updated 2 years ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: wifi: wfx: fix memory leak when starting AP Kmemleak reported this error: unreferenced object 0xd73d1180 (size 184): comm "wpa_supplicant", pid 1559, jiffies 13006305 (age 964.245s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 1e 00 01 00 00 00 00 00 ................ backtrace: [<5ca11420>] kmem_cache_alloc+0x20c/0x5ac [<127bdd74>] __alloc_skb+0x144/0x170 [<fb8a5e38>] __netdev_alloc_skb+0x50/0x180 [<0f9fa1d5>] __ieee80211_beacon_get+0x290/0x4d4 [mac80211] [<7accd02d>] ieee80211_beacon_get_tim+0x54/0x18c [mac80211] [<41e25cc3>] wfx_start_ap+0xc8/0x234 [wfx] [<93a70356>] ieee80211_start_ap+0x404/0x6b4 [mac80211] [<a4a661cd>] nl80211_start_ap+0x76c/0x9e0 [cfg80211] [<47bd8b68>] genl_rcv_msg+0x198/0x378 [<453ef796>] netlink_rcv_skb+0xd0/0x130 [<6b7c977a>] genl_rcv+0x34/0x44 [<66b2d04d>] netlink_unicast+0x1b4/0x258 [<f965b9b6>] netlink_sendmsg+0x1e8/0x428 [<aadb8231>] ____sys_sendmsg+0x1e0/0x274 [<d2b5212d>] ___sys_sendmsg+0x80/0xb4 [<69954f45>] __sys_sendmsg+0x64/0xa8 unreferenced object 0xce087000 (size 1024): comm "wpa_supplicant", pid 1559, jiffies 13006305 (age 964.246s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 10 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00 ...@............ backtrace: [<9a993714>] __kmalloc_track_caller+0x230/0x600 [<f83ea192>] kmalloc_reserve.constprop.0+0x30/0x74 [<a2c61343>] __alloc_skb+0xa0/0x170 [<fb8a5e38>] __netdev_alloc_skb+0x50/0x180 [<0f9fa1d5>] __ieee80211_beacon_get+0x290/0x4d4 [mac80211] [<7accd02d>] ieee80211_beacon_get_tim+0x54/0x18c [mac80211] [<41e25cc3>] wfx_start_ap+0xc8/0x234 [wfx] [<93a70356>] ieee80211_start_ap+0x404/0x6b4 [mac80211] [<a4a661cd>] nl80211_start_ap+0x76c/0x9e0 [cfg80211] [<47bd8b68>] genl_rcv_msg+0x198/0x378 [<453ef796>] netlink_rcv_skb+0xd0/0x130 [<6b7c977a>] genl_rcv+0x34/0x44 [<66b2d04d>] netlink_unicast+0x1b4/0x258 [<f965b9b6>] netlink_sendmsg+0x1e8/0x428 [<aadb8231>] ____sys_sendmsg+0x1e0/0x274 [<d2b5212d>] ___sys_sendmsg+0x80/0xb4 However, since the kernel is build optimized, it seems the stack is not accurate. It appears the issue is related to wfx_set_mfp_ap(). The issue is obvious in this function: memory allocated by ieee80211_beacon_get() is never released. Fixing this leak makes kmemleak happy.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-125

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: net: gro: properly validate BIG TCP aggregation criteria When GRO attempts to aggregate packets beyond GRO_LEGACY_MAX_SIZE (64KB), BIG TCP should only be permitted for plain IPv4 TCP and plain IPv6 TCP (with sufficient MAC header room to insert the temporary HBH jumbo header). However, commit b1a78b9b9886 ("net: add support for ipv4 big tcp") loosened the check in skb_gro_receive(), leading to several issues: 1. skb_gro_receive() checked skb_headroom(p) instead of the actual space before the MAC header (p->mac_header). Because skb_headroom(p) includes mac_len, crafted frames (e.g. injected via AF_PACKET) can pass the check with p->mac_header < 8 bytes. When ipv6_gro_complete() inserts the temporary HBH jumbo header, the memmove() starts before skb->head, causing an out-of-bounds write and wrapping skb->mac_header. 2. It allowed non-IP protocols such as software VLAN (ETH_P_8021Q / ETH_P_8021AD) to aggregate beyond 64KB because p->protocol != ETH_P_IPV6 was true. 3. It checked p->encapsulation instead of NAPI_GRO_CB(skb)->encap_mark, allowing encapsulated flows (e.g. SIT / IPv6-in-IPv4) to aggregate beyond 64KB. Fix skb_gro_receive() to strictly enforce: - NAPI_GRO_CB(skb)->proto == IPPROTO_TCP - Not encapsulated (!NAPI_GRO_CB(skb)->encap_mark && !p->encapsulation) - Protocol must be either ETH_P_IP or ETH_P_IPV6 - If ETH_P_IPV6, p->mac_header must be at least sizeof(struct hop_jumbo_hdr) Returning -E2BIG from skb_gro_receive() ensures that packets which cannot become BIG TCP are cleanly flushed at <= 64KB and delivered intact without dropping. This issue does not exist in mainline (7.0+) because the subsystem was rewritten in commit 81be30c1f5f2 ("net/ipv6: Drop HBH for BIG TCP on RX side"), making this fix relevant only for older stable branches like 6.18.y.CVE-2026-80725