CVE-2025-38581

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

crypto: ccp - Fix crash when rebind ccp device for ccp.ko

When CONFIG_CRYPTO_DEV_CCP_DEBUGFS is enabled, rebinding the ccp device causes the following crash:

$ echo 0000:0a:00.2 > /sys/bus/pci/drivers/ccp/unbind $ echo 0000:0a:00.2 > /sys/bus/pci/drivers/ccp/bind

[ 204.976930] BUG: kernel NULL pointer dereference, address: 0000000000000098 [ 204.978026] #PF: supervisor write access in kernel mode [ 204.979126] #PF: error_code(0x0002) - not-present page [ 204.980226] PGD 0 P4D 0 [ 204.981317] Oops: Oops: 0002 [#1] SMP NOPTI … [ 204.997852] Call Trace: [ 204.999074] [ 205.000297] start_creating+0x9f/0x1c0 [ 205.001533] debugfs_create_dir+0x1f/0x170 [ 205.002769] ? srso_return_thunk+0x5/0x5f [ 205.004000] ccp5_debugfs_setup+0x87/0x170 [ccp] [ 205.005241] ccp5_init+0x8b2/0x960 [ccp] [ 205.006469] ccp_dev_init+0xd4/0x150 [ccp] [ 205.007709] sp_init+0x5f/0x80 [ccp] [ 205.008942] sp_pci_probe+0x283/0x2e0 [ccp] [ 205.010165] ? srso_return_thunk+0x5/0x5f [ 205.011376] local_pci_probe+0x4f/0xb0 [ 205.012584] pci_device_probe+0xdb/0x230 [ 205.013810] really_probe+0xed/0x380 [ 205.015024] __driver_probe_device+0x7e/0x160 [ 205.016240] device_driver_attach+0x2f/0x60 [ 205.017457] bind_store+0x7c/0xb0 [ 205.018663] drv_attr_store+0x28/0x40 [ 205.019868] sysfs_kf_write+0x5f/0x70 [ 205.021065] kernfs_fop_write_iter+0x145/0x1d0 [ 205.022267] vfs_write+0x308/0x440 [ 205.023453] ksys_write+0x6d/0xe0 [ 205.024616] __x64_sys_write+0x1e/0x30 [ 205.025778] x64_sys_call+0x16ba/0x2150 [ 205.026942] do_syscall_64+0x56/0x1e0 [ 205.028108] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 205.029276] RIP: 0033:0x7fbc36f10104 [ 205.030420] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 e1 08 2e 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5

This patch sets ccp_debugfs_dir to NULL after destroying it in ccp5_debugfs_destroy, allowing the directory dentry to be recreated when rebinding the ccp device.

Tested on AMD Ryzen 7 1700X.

Weakness

The product dereferences a pointer that it expects to be valid but is NULL.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/181698af38d3f93381229ad89c09b5bd0496661a
• https://git.kernel.org/stable/c/20c0ed8dd65834e6bab464f54cd6ff68659bacb9
• https://git.kernel.org/stable/c/2d4060f05e74dbee884ba723f6afd9282befc3c5
• https://git.kernel.org/stable/c/64ec9a7e7a6398b172ab6feba60e952163a1c3d5
• https://git.kernel.org/stable/c/6eadf50c1d894cb34f3237064063207460946040
• https://git.kernel.org/stable/c/9dea08eac4f6d6fbbae59992978252e2edab995d
• https://git.kernel.org/stable/c/a25ab6dfa0ce323ec308966988be6b675eb9d3e5
• https://git.kernel.org/stable/c/ce63a83925964ab7564bd216bd92b80bc365492e
• https://git.kernel.org/stable/c/db111468531777cac8b4beb6515a88a54b0c4a74
• https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html