First published: Thu Feb 22 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a race condition between btf_put() and map_free() When running `./test_progs -j` in my local vm with latest kernel, I once hit a kasan error like below: [ 1887.184724] BUG: KASAN: slab-use-after-free in bpf_rb_root_free+0x1f8/0x2b0 [ 1887.185599] Read of size 4 at addr ffff888106806910 by task kworker/u12:2/2830 [ 1887.186498] [ 1887.186712] CPU: 3 PID: 2830 Comm: kworker/u12:2 Tainted: G OEL 6.7.0-rc3-00699-g90679706d486-dirty #494 [ 1887.188034] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 1887.189618] Workqueue: events_unbound bpf_map_free_deferred [ 1887.190341] Call Trace: [ 1887.190666] <TASK> [ 1887.190949] dump_stack_lvl+0xac/0xe0 [ 1887.191423] ? nf_tcp_handle_invalid+0x1b0/0x1b0 [ 1887.192019] ? panic+0x3c0/0x3c0 [ 1887.192449] print_report+0x14f/0x720 [ 1887.192930] ? preempt_count_sub+0x1c/0xd0 [ 1887.193459] ? __virt_addr_valid+0xac/0x120 [ 1887.194004] ? bpf_rb_root_free+0x1f8/0x2b0 [ 1887.194572] kasan_report+0xc3/0x100 [ 1887.195085] ? bpf_rb_root_free+0x1f8/0x2b0 [ 1887.195668] bpf_rb_root_free+0x1f8/0x2b0 [ 1887.196183] ? __bpf_obj_drop_impl+0xb0/0xb0 [ 1887.196736] ? preempt_count_sub+0x1c/0xd0 [ 1887.197270] ? preempt_count_sub+0x1c/0xd0 [ 1887.197802] ? _raw_spin_unlock+0x1f/0x40 [ 1887.198319] bpf_obj_free_fields+0x1d4/0x260 [ 1887.198883] array_map_free+0x1a3/0x260 [ 1887.199380] bpf_map_free_deferred+0x7b/0xe0 [ 1887.199943] process_scheduled_works+0x3a2/0x6c0 [ 1887.200549] worker_thread+0x633/0x890 [ 1887.201047] ? __kthread_parkme+0xd7/0xf0 [ 1887.201574] ? kthread+0x102/0x1d0 [ 1887.202020] kthread+0x1ab/0x1d0 [ 1887.202447] ? pr_cont_work+0x270/0x270 [ 1887.202954] ? kthread_blkcg+0x50/0x50 [ 1887.203444] ret_from_fork+0x34/0x50 [ 1887.203914] ? kthread_blkcg+0x50/0x50 [ 1887.204397] ret_from_fork_asm+0x11/0x20 [ 1887.204913] </TASK> [ 1887.204913] </TASK> [ 1887.205209] [ 1887.205416] Allocated by task 2197: [ 1887.205881] kasan_set_track+0x3f/0x60 [ 1887.206366] __kasan_kmalloc+0x6e/0x80 [ 1887.206856] __kmalloc+0xac/0x1a0 [ 1887.207293] btf_parse_fields+0xa15/0x1480 [ 1887.207836] btf_parse_struct_metas+0x566/0x670 [ 1887.208387] btf_new_fd+0x294/0x4d0 [ 1887.208851] __sys_bpf+0x4ba/0x600 [ 1887.209292] __x64_sys_bpf+0x41/0x50 [ 1887.209762] do_syscall_64+0x4c/0xf0 [ 1887.210222] entry_SYSCALL_64_after_hwframe+0x63/0x6b [ 1887.210868] [ 1887.211074] Freed by task 36: [ 1887.211460] kasan_set_track+0x3f/0x60 [ 1887.211951] kasan_save_free_info+0x28/0x40 [ 1887.212485] ____kasan_slab_free+0x101/0x180 [ 1887.213027] __kmem_cache_free+0xe4/0x210 [ 1887.213514] btf_free+0x5b/0x130 [ 1887.213918] rcu_core+0x638/0xcc0 [ 1887.214347] __do_softirq+0x114/0x37e The error happens at bpf_rb_root_free+0x1f8/0x2b0: 00000000000034c0 <bpf_rb_root_free>: ; { 34c0: f3 0f 1e fa endbr64 34c4: e8 00 00 00 00 callq 0x34c9 <bpf_rb_root_free+0x9> 34c9: 55 pushq %rbp 34ca: 48 89 e5 movq %rsp, %rbp ... ; if (rec && rec->refcount_off >= 0 && 36aa: 4d 85 ed testq %r13, %r13 36ad: 74 a9 je 0x3658 <bpf_rb_root_free+0x198> 36af: 49 8d 7d 10 leaq 0x10(%r13), %rdi 36b3: e8 00 00 00 00 callq 0x36b8 <bpf_rb_root_free+0x1f8> <==== kasan function 36b8: 45 8b 7d 10 movl 0x10(%r13), %r15d <==== use-after-free load 36bc: 45 85 ff testl %r15d, %r15d 36bf: 78 8c js 0x364d <bpf_rb_root_free+0x18d> So the problem ---truncated---
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Software | Affected Version | How to fix |
---|---|---|
Linux Linux kernel | >=6.2.0<6.6.14 | |
Linux Linux kernel | >=6.7.0<6.7.2 | |
ubuntu/linux | <6.5.0-41.41 | 6.5.0-41.41 |
ubuntu/linux | <6.8~ | 6.8~ |
ubuntu/linux-aws | <6.5.0-1021.21 | 6.5.0-1021.21 |
ubuntu/linux-aws | <6.8~ | 6.8~ |
ubuntu/linux-aws-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-aws-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-aws-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-aws-fips | <6.8~ | 6.8~ |
ubuntu/linux-aws-hwe | <6.8~ | 6.8~ |
ubuntu/linux-azure | <6.5.0-1022.23 | 6.5.0-1022.23 |
ubuntu/linux-azure | <6.8~ | 6.8~ |
ubuntu/linux-azure-4.15 | <6.8~ | 6.8~ |
ubuntu/linux-azure-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-azure-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-azure-6.5 | <6.5.0-1022.23~22.04.1 | 6.5.0-1022.23~22.04.1 |
ubuntu/linux-azure-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-azure-fde | <6.8~ | 6.8~ |
ubuntu/linux-azure-fde-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-azure-fips | <6.8~ | 6.8~ |
ubuntu/linux-bluefield | <6.8~ | 6.8~ |
ubuntu/linux-fips | <6.8~ | 6.8~ |
ubuntu/linux-gcp | <6.5.0-1022.24 | 6.5.0-1022.24 |
ubuntu/linux-gcp | <6.8~ | 6.8~ |
ubuntu/linux-gcp-4.15 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-6.5 | <6.5.0-1022.24~22.04.1 | 6.5.0-1022.24~22.04.1 |
ubuntu/linux-gcp-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-fips | <6.8~ | 6.8~ |
ubuntu/linux-gke | <6.8~ | 6.8~ |
ubuntu/linux-gkeop | <6.8~ | 6.8~ |
ubuntu/linux-gkeop-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-hwe | <6.8~ | 6.8~ |
ubuntu/linux-hwe-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-hwe-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-hwe-6.5 | <6.5.0-41.41~22.04.2 | 6.5.0-41.41~22.04.2 |
ubuntu/linux-hwe-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-ibm | <6.8~ | 6.8~ |
ubuntu/linux-ibm-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-ibm-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-intel | <6.8~ | 6.8~ |
ubuntu/linux-intel-iotg | <6.8~ | 6.8~ |
ubuntu/linux-intel-iotg-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-iot | <6.8~ | 6.8~ |
ubuntu/linux-kvm | <6.8~ | 6.8~ |
ubuntu/linux-laptop | <6.5.0-1017.20 | 6.5.0-1017.20 |
ubuntu/linux-laptop | <6.8~ | 6.8~ |
ubuntu/linux-lowlatency | <6.5.0-41.41.1 | 6.5.0-41.41.1 |
ubuntu/linux-lowlatency | <6.8~ | 6.8~ |
ubuntu/linux-lowlatency-hwe-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-lowlatency-hwe-6.5 | <6.5.0-41.41.1~22.04.1 | 6.5.0-41.41.1~22.04.1 |
ubuntu/linux-lowlatency-hwe-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-lts-xenial | <6.8~ | 6.8~ |
ubuntu/linux-nvidia | <6.8~ | 6.8~ |
ubuntu/linux-nvidia-6.5 | <6.5.0-1021.22 | 6.5.0-1021.22 |
ubuntu/linux-nvidia-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-nvidia-6.8 | <6.8~ | 6.8~ |
ubuntu/linux-nvidia-lowlatency | <6.8~ | 6.8~ |
ubuntu/linux-oem-6.5 | <6.5.0-1024.25 | 6.5.0-1024.25 |
ubuntu/linux-oem-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-oem-6.8 | <6.8~ | 6.8~ |
ubuntu/linux-oracle | <6.5.0-1024.24 | 6.5.0-1024.24 |
ubuntu/linux-oracle | <6.8~ | 6.8~ |
ubuntu/linux-oracle-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-oracle-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-oracle-6.5 | <6.5.0-1024.24~22.04.1 | 6.5.0-1024.24~22.04.1 |
ubuntu/linux-oracle-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-raspi | <6.5.0-1018.21 | 6.5.0-1018.21 |
ubuntu/linux-raspi | <6.8~ | 6.8~ |
ubuntu/linux-raspi-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-riscv | <6.5.0-40.40.1 | 6.5.0-40.40.1 |
ubuntu/linux-riscv | <6.8~ | 6.8~ |
ubuntu/linux-riscv-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-riscv-6.5 | <6.5.0-40.40.1~22.04.1 | 6.5.0-40.40.1~22.04.1 |
ubuntu/linux-riscv-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-starfive | <6.5.0-1015.16 | 6.5.0-1015.16 |
ubuntu/linux-starfive | <6.8~ | 6.8~ |
ubuntu/linux-starfive-6.5 | <6.5.0-1015.16~22.04.1 | 6.5.0-1015.16~22.04.1 |
ubuntu/linux-starfive-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-xilinx-zynqmp | <6.8~ | 6.8~ |
debian/linux | 5.10.223-1 6.1.106-3 6.1.99-1 6.10.6-1 6.10.7-1 |
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(Appears in the following advisories)