Bug 219181
| Summary: | KASAN: null-ptr-deref in bpf_core_calc_relo_insn | ||
|---|---|---|---|
| Product: | Linux | Reporter: | RuiTong Liu (cnitlrt) |
| Component: | Kernel | Assignee: | Virtual assignee for kernel bugs (linux-kernel) |
| Status: | NEW --- | ||
| Severity: | normal | CC: | cnitlrt |
| Priority: | P3 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | <=linux-6.11-rc4 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: | the poc file | ||
I use gdb debug it,and found that the lack of a NULL check before using local_type has led to a null pointer dereference vulnerability.
```
───────────────────────────────────────────────────────────────────────────[ REGISTERS / show-flags off / show-compact-regs off ]───────────────────────────────────────────────────────────────────────────
RAX 0xdffffc0000000000
RBX 0xdffffc0000000000
RCX 0xffffffff816c8b8b (btf_type_by_id+235) ◂— 0x404be85576e53944
RDX 0x0
RDI 0x4
RSI 0xffffffff816c8bea (btf_type_by_id+330) ◂— 0xe0894c5d5be43145
R8 0xffff88811669f778 ◂— 0x0
R9 0xffff888115f48000 ◂— 0x0
R10 0x4
R11 0xffff888104562080 ◂— 0x0
R12 0x0
R13 0xffff8881135b7000 —▸ 0xffff8881166280c2 ◂— 0x0
R14 0x4
R15 0xffff888115f48000 ◂— 0x0
RBP 0xffff88811669f6c0 —▸ 0xffff88811669f798 —▸ 0xffffffff8160fcb0 (check_btf_line) ◂— 0x56415741e5894855
RSP 0xffff88811669f3d0 ◂— 0x1ffff11022cd3e92
*RIP 0xffffffff8173e51e (bpf_core_calc_relo_insn+286) ◂— 0x83e0894c0214b60f
────────────────────────────────────────────────────────────────────────────────────[ DISASM / x86-64 / set emulate on ]────────────────────────────────────────────────────────────────────────────────────
0xffffffff8173e505 <bpf_core_calc_relo_insn+261> call btf_type_by_id <btf_type_by_id>
0xffffffff8173e50a <bpf_core_calc_relo_insn+266> mov rdx, rax
0xffffffff8173e50d <bpf_core_calc_relo_insn+269> mov r12, rax
0xffffffff8173e510 <bpf_core_calc_relo_insn+272> movabs rax, 0xdffffc0000000000
0xffffffff8173e51a <bpf_core_calc_relo_insn+282> shr rdx, 3 <fixed_percpu_data+3>
► 0xffffffff8173e51e <bpf_core_calc_relo_insn+286> movzx edx, byte ptr [rdx + rax]
0xffffffff8173e522 <bpf_core_calc_relo_insn+290> mov rax, r12
0xffffffff8173e525 <bpf_core_calc_relo_insn+293> and eax, 7 <fixed_percpu_data+7>
0xffffffff8173e528 <bpf_core_calc_relo_insn+296> add eax, 3 <fixed_percpu_data+3>
0xffffffff8173e52b <bpf_core_calc_relo_insn+299> cmp al, dl
0xffffffff8173e52d <bpf_core_calc_relo_insn+301> jl bpf_core_calc_relo_insn+311 <bpf_core_calc_relo_insn+311>
─────────────────────────────────────────────────────────────────────────────────────────────[ SOURCE (CODE) ]──────────────────────────────────────────────────────────────────────────────────────────────
In file: /home/ubuntu/linux-6.11-rc4/tools/lib/bpf/relo_core.c:1300
1295 char spec_buf[256];
1296 int i, j, err;
1297
1298 local_id = relo->type_id;
1299 local_type = btf_type_by_id(local_btf, local_id);
► 1300 local_name = btf__name_by_offset(local_btf, local_type->name_off);
1301 if (!local_name)
1302 return -EINVAL;
1303
1304 err = bpf_core_parse_spec(prog_name, local_btf, relo, local_spec);
1305 if (err) {
─────────────────────────────────────────────────────────────────────────────────────────────────[ STACK ]──────────────────────────────────────────────────────────────────────────────────────────────────
```
|
Created attachment 306758 [details] the poc file I found a bug in the Linux kernel version 6.11.0-rc4 using syzkaller. Here is the crash information ``` [ 89.482115] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI [ 89.482639] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [ 89.482979] CPU: 1 UID: 0 PID: 214 Comm: test Not tainted 6.11.0-rc4 #1 [ 89.483276] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 89.483632] RIP: 0010:bpf_core_calc_relo_insn+0x11e/0x1e90 [ 89.483885] Code: 48 8b 85 28 fd ff ff 4c 89 ef 44 8b 70 04 44 89 f6 e8 96 a5 f8 ff 48 89 c2 49 89 c4 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14c [ 89.484686] RSP: 0018:ffff888108f373d0 EFLAGS: 00010246 [ 89.484924] RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: ffffffff816c8b8b [ 89.485247] RDX: 0000000000000000 RSI: ffffffff816c8bea RDI: 0000000000000004 [ 89.485563] RBP: ffff888108f376c0 R08: ffff888108f37778 R09: ffff88810991c000 [ 89.485880] R10: 0000000000000004 R11: ffff888103ab1c90 R12: 0000000000000000 [ 89.486197] R13: ffff888103ddfe00 R14: 0000000000000004 R15: ffff88810991c000 [ 89.486514] FS: 00007f94a2d15640(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 [ 89.486874] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 89.487128] CR2: 0000000020000480 CR3: 0000000106058000 CR4: 00000000003006f0 [ 89.487439] Call Trace: [ 89.487553] <TASK> [ 89.487654] ? show_regs+0x93/0xa0 [ 89.487815] ? die_addr+0x50/0xd0 [ 89.487972] ? exc_general_protection+0x19f/0x320 [ 89.488185] ? asm_exc_general_protection+0x26/0x30 [ 89.488405] ? btf_type_by_id+0xeb/0x1a0 [ 89.488584] ? btf_type_by_id+0x14a/0x1a0 [ 89.488766] ? bpf_core_calc_relo_insn+0x11e/0x1e90 [ 89.488989] ? __printk_safe_exit+0x9/0x20 [ 89.489175] ? stack_depot_save_flags+0x616/0x7c0 [ 89.489392] ? bpf_prog_load+0x151c/0x2450 [ 89.489594] ? kasan_save_stack+0x34/0x50 [ 89.489792] ? kasan_save_stack+0x24/0x50 [ 89.489987] ? __pfx_bpf_core_calc_relo_insn+0x10/0x10 [ 89.490231] ? bpf_check+0x6744/0xba00 [ 89.490415] ? bpf_prog_load+0x151c/0x2450 [ 89.490612] ? __sys_bpf+0x12be/0x5290 [ 89.490795] ? __x64_sys_bpf+0x78/0xc0 [ 89.490979] ? do_syscall_64+0xa6/0x1a0 [ 89.491167] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 89.491417] ? __pfx_vsnprintf+0x10/0x10 [ 89.491611] ? sort_r+0x45/0x5f0 [ 89.491774] ? _copy_to_user+0x77/0x90 [ 89.491954] ? bpf_verifier_vlog+0x25b/0x690 [ 89.492150] ? __pfx_sort+0x10/0x10 [ 89.492314] ? verbose+0xde/0x170 [ 89.492470] ? kasan_unpoison+0x27/0x60 [ 89.492648] ? __kasan_slab_alloc+0x30/0x70 [ 89.492837] ? __kmalloc_cache_noprof+0xf0/0x270 [ 89.493050] bpf_core_apply+0x48b/0xaf0 [ 89.493228] ? btf_name_by_offset+0x13a/0x180 [ 89.493431] ? __pfx_bpf_core_apply+0x10/0x10 [ 89.493631] ? __pfx_check_btf_line+0x10/0x10 [ 89.493830] ? bpf_check_uarg_tail_zero+0x142/0x1c0 [ 89.494051] ? __pfx_bpf_check_uarg_tail_zero+0x10/0x10 [ 89.494286] bpf_check+0x6744/0xba00 [ 89.494458] ? kasan_save_stack+0x34/0x50 [ 89.494653] ? kasan_save_stack+0x24/0x50 [ 89.494848] ? kasan_save_track+0x14/0x30 [ 89.495039] ? __kasan_kmalloc+0x7f/0x90 [ 89.495232] ? __pfx_bpf_check+0x10/0x10 [ 89.495426] ? pcpu_chunk_relocate+0x145/0x1c0 [ 89.495640] ? mutex_unlock+0x7e/0xd0 [ 89.495820] ? kasan_unpoison+0x27/0x60 [ 89.496008] ? __kasan_slab_alloc+0x30/0x70 [ 89.496208] ? __kmalloc_cache_noprof+0xf0/0x270 [ 89.496430] ? kasan_save_track+0x14/0x30 [ 89.496622] ? __kasan_kmalloc+0x7f/0x90 [ 89.496810] ? selinux_bpf_prog_load+0x15b/0x1c0 [ 89.497024] bpf_prog_load+0x151c/0x2450 [ 89.497206] ? __pfx_bpf_prog_load+0x10/0x10 [ 89.497405] ? avc_has_perm+0x175/0x2f0 [ 89.497585] ? __pte_offset_map+0x12f/0x1f0 [ 89.497774] ? bpf_check_uarg_tail_zero+0x142/0x1c0 [ 89.497994] ? selinux_bpf+0xdd/0x120 [ 89.498163] ? security_bpf+0x8d/0xb0 [ 89.498333] __sys_bpf+0x12be/0x5290 [ 89.498500] ? folio_add_lru+0x58/0x80 [ 89.498675] ? __pfx___sys_bpf+0x10/0x10 [ 89.498855] ? __pfx_down_read_trylock+0x10/0x10 [ 89.499069] ? __pfx___handle_mm_fault+0x10/0x10 [ 89.499283] ? do_user_addr_fault+0x595/0x1220 [ 89.499524] __x64_sys_bpf+0x78/0xc0 [ 89.499738] ? exc_page_fault+0xae/0x180 [ 89.499928] do_syscall_64+0xa6/0x1a0 [ 89.500109] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 89.500361] RIP: 0033:0x44ceed [ 89.500512] Code: c3 e8 d7 1e 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 018 [ 89.501348] RSP: 002b:00007f94a2d15178 EFLAGS: 00000287 ORIG_RAX: 0000000000000141 [ 89.501695] RAX: ffffffffffffffda RBX: 00007f94a2d15640 RCX: 000000000044ceed [ 89.502013] RDX: 0000000000000090 RSI: 0000000020000480 RDI: 0000000000000005 [ 89.502323] RBP: 00007f94a2d151a0 R08: 0000000000000000 R09: 0000000000000000 [ 89.502635] R10: 0000000000000000 R11: 0000000000000287 R12: 00007f94a2d15640 [ 89.502949] R13: 0000000000000000 R14: 00000000004160d0 R15: 00007f94a2cf5000 [ 89.503269] </TASK> [ 89.503376] Modules linked in: [ 89.503586] ---[ end trace 0000000000000000 ]--- [ 89.503793] RIP: 0010:bpf_core_calc_relo_insn+0x11e/0x1e90 [ 89.504045] Code: 48 8b 85 28 fd ff ff 4c 89 ef 44 8b 70 04 44 89 f6 e8 96 a5 f8 ff 48 89 c2 49 89 c4 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14c [ 89.504860] RSP: 0018:ffff888108f373d0 EFLAGS: 00010246 [ 89.505112] RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: ffffffff816c8b8b [ 89.505441] RDX: 0000000000000000 RSI: ffffffff816c8bea RDI: 0000000000000004 [ 89.505768] RBP: ffff888108f376c0 R08: ffff888108f37778 R09: ffff88810991c000 [ 89.506099] R10: 0000000000000004 R11: ffff888103ab1c90 R12: 0000000000000000 [ 89.506427] R13: ffff888103ddfe00 R14: 0000000000000004 R15: ffff88810991c000 [ 89.506754] FS: 00007f94a2d15640(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 [ 89.507129] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 89.507398] CR2: 0000000020000480 CR3: 0000000106058000 CR4: 00000000003006f0 ``` I use gdb debug it,and found that the lack of a NULL check before using local_type has led to a null pointer dereference vulnerability.