CVE-2022-49797

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

tracing: kprobe: Fix potential null-ptr-deref on traceeventfile in kprobeeventgentestexit()

When tracegeteventfile() failed, genkretprobetest will be assigned as the error code. If module kprobeeventgentest is removed now, the null pointer dereference will happen in kprobeeventgentestexit(). Check if genkprobetest or genkretprobetest is error code or NULL before dereference them.

BUG: kernel NULL pointer dereference, address: 0000000000000012 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 3 PID: 2210 Comm: modprobe Not tainted 6.1.0-rc1-00171-g2159299a3b74-dirty #217 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:kprobeeventgentestexit+0x1c/0xb5 [kprobeeventgentest] Code: Unable to access opcode bytes at 0xffffffff9ffffff2. RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246 RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000 RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800 R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f56b75be540(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> _x64sysdeletemodule+0x206/0x380 ? lockdephardirqsonprepare+0xd8/0x190 ? syscallenterfromusermode+0x1c/0x50 dosyscall64+0x3f/0x90 entrySYSCALL64afterhwframe+0x63/0xcd