can: bcm: Fix UAF in bcm_proc_show()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: can: bcm: Fix UAF in bcm_proc_show() BUG: KASAN: slab-use-after-free in bcm_proc_show+0x969/0xa80 Read of size 8 at addr ffff888155846230 by task cat/7862 CPU: 1 PID: 7862 Comm: cat Not tainted 6.5.0-rc1-00153-gc8746099c197 #230 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0xd5/0x150 print_report+0xc1/0x5e0 kasan_report+0xba/0xf0 bcm_proc_show+0x969/0xa80 seq_read_iter+0x4f6/0x1260 seq_read+0x165/0x210 proc_reg_read+0x227/0x300 vfs_read+0x1d5/0x8d0 ksys_read+0x11e/0x240 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Allocated by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0x9e/0xa0 bcm_sendmsg+0x264b/0x44e0 sock_sendmsg+0xda/0x180 ____sys_sendmsg+0x735/0x920 ___sys_sendmsg+0x11d/0x1b0 __sys_sendmsg+0xfa/0x1d0 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x27/0x40 ____kasan_slab_free+0x161/0x1c0 slab_free_freelist_hook+0x119/0x220 __kmem_cache_free+0xb4/0x2e0 rcu_core+0x809/0x1bd0 bcm_op is freed before procfs entry be removed in bcm_release(), this lead to bcm_proc_show() may read the freed bcm_op.

References

• https://git.kernel.org/stable/c/11b8e27ed448baa385d90154a141466bd5e92f18
• https://git.kernel.org/stable/c/9b58d36d0c1ea29a9571e0222a9c29df0ccfb7ff
• https://git.kernel.org/stable/c/9533dbfac0ff7edd77a5fa2c24974b1d66c8b0a6
• https://git.kernel.org/stable/c/cf254b4f68e480e73dab055014e002b77aed30ed
• https://git.kernel.org/stable/c/3c3941bb1eb53abe7d640ffee5c4d6b559829ab3
• https://git.kernel.org/stable/c/995f47d76647708ec26c6e388663ad4f3f264787
• https://git.kernel.org/stable/c/dfd0aa26e9a07f2ce546ccf8304ead6a2914e8a7
• https://git.kernel.org/stable/c/55c3b96074f3f9b0aee19bf93cd71af7516582bb