CVE-2024-26901

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

do_sys_name_to_handle(): use kzalloc() to fix kernel-infoleak

syzbot identified a kernel information leak vulnerability in do_sys_name_to_handle() and issued the following report [1].

[1] BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x100 lib/usercopy.c:40 instrument_copy_to_user include/linux/instrumented.h:114 [inline] _copy_to_user+0xbc/0x100 lib/usercopy.c:40 copy_to_user include/linux/uaccess.h:191 [inline] do_sys_name_to_handle fs/fhandle.c:73 [inline] __do_sys_name_to_handle_at fs/fhandle.c:112 [inline] __se_sys_name_to_handle_at+0x949/0xb10 fs/fhandle.c:94 __x64_sys_name_to_handle_at+0xe4/0x140 fs/fhandle.c:94 …

Uninit was created at: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] __kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc+0x121/0x3c0 mm/slab_common.c:1020 kmalloc include/linux/slab.h:604 [inline] do_sys_name_to_handle fs/fhandle.c:39 [inline] __do_sys_name_to_handle_at fs/fhandle.c:112 [inline] __se_sys_name_to_handle_at+0x441/0xb10 fs/fhandle.c:94 __x64_sys_name_to_handle_at+0xe4/0x140 fs/fhandle.c:94 …

Bytes 18-19 of 20 are uninitialized Memory access of size 20 starts at ffff888128a46380 Data copied to user address 0000000020000240

Per Chuck Levers suggestion, use kzalloc() instead of kmalloc() to solve the problem.

Weakness

The product uses or accesses a resource that has not been initialized.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/3948abaa4e2be938ccdfc289385a27342fb13d43
• https://git.kernel.org/stable/c/423b6bdf19bbc5e1f7e7461045099917378f7e71
• https://git.kernel.org/stable/c/4bac28f441e3cc9d3f1a84c8d023228a68d8a7c1
• https://git.kernel.org/stable/c/772a7def9868091da3bcb0d6c6ff9f0c03d7fa8b
• https://git.kernel.org/stable/c/bf9ec1b24ab4e94345aa1c60811dd329f069c38b
• https://git.kernel.org/stable/c/c1362eae861db28b1608b9dc23e49634fe87b63b
• https://git.kernel.org/stable/c/cba138f1ef37ec6f961baeab62f312dedc7cf730
• https://git.kernel.org/stable/c/cde76b3af247f615447bcfecf610bb76c3529126
• https://git.kernel.org/stable/c/e6450d5e46a737a008b4885aa223486113bf0ad6