CVE-2023-53578: net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-04 · updated 2026-06-17
Weakness: CWE-908

Description

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume() Syzbot reported a bug as following: ===================================================== BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230 qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230 qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108 call_write_iter include/linux/fs.h:2189 [inline] aio_write+0x63a/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was created at: slab_post_alloc_hook mm/slab.h:766 [inline] slab_alloc_node mm/slub.c:3452 [inline] __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:967 [inline] __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988 kmalloc_reserve net/core/skbuff.c:492 [inline] __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565 __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630 qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108 call_write_iter include/linux/fs.h:2189 [inline] aio_write+0x63a/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt) in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post(). But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot scenario. This triggers the uninit variable access bug. Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() to fix the bug.

Affected products

Linux kernel: from 5.6 before 5.10.178; from 5.11 before 5.15.108; from 5.16 before 6.1.25; from 6.2 before 6.2.12; 6.3-rc1, 6.3-rc2, 6.3-rc3, 6.3-rc4, 6.3-rc5, 6.3-rc6 — fixed in 5.10.178, 5.15.108, 6.1.25, 6.2.12

How to fix

Upgrade to a fixed version: Linux kernel 5.10.178, 5.15.108, 6.1.25, 6.2.12. Check the vendor advisory for mitigations.

References

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