AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity
35ab8c9085
kernel_optimize_test/kernel/bpf
History
Daniel Borkmann 35ab8c9085 bpf: Fix out of bounds access from invalid *_or_null type verification 
[ no upstream commit given implicitly fixed through the larger refactoring
  in c25b2ae136039ffa820c26138ed4a5e5f3ab3841 ]

While auditing some other code, I noticed missing checks inside the pointer
arithmetic simulation, more specifically, adjust_ptr_min_max_vals(). Several
*_OR_NULL types are not rejected whereas they are _required_ to be rejected
given the expectation is that they get promoted into a 'real' pointer type
for the success case, that is, after an explicit != NULL check.

One case which stands out and is accessible from unprivileged (iff enabled
given disabled by default) is BPF ring buffer. From crafting a PoC, the NULL
check can be bypassed through an offset, and its id marking will then lead
to promotion of mem_or_null to a mem type.

bpf_ringbuf_reserve() helper can trigger this case through passing of reserved
flags, for example.

  func#0 @0
  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  0: (7a) *(u64 *)(r10 -8) = 0
  1: R1=ctx(id=0,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm
  1: (18) r1 = 0x0
  3: R1_w=map_ptr(id=0,off=0,ks=0,vs=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm
  3: (b7) r2 = 8
  4: R1_w=map_ptr(id=0,off=0,ks=0,vs=0,imm=0) R2_w=invP8 R10=fp0 fp-8_w=mmmmmmmm
  4: (b7) r3 = 0
  5: R1_w=map_ptr(id=0,off=0,ks=0,vs=0,imm=0) R2_w=invP8 R3_w=invP0 R10=fp0 fp-8_w=mmmmmmmm
  5: (85) call bpf_ringbuf_reserve#131
  6: R0_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  6: (bf) r6 = r0
  7: R0_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R6_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  7: (07) r0 += 1
  8: R0_w=mem_or_null(id=2,ref_obj_id=2,off=1,imm=0) R6_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  8: (15) if r0 == 0x0 goto pc+4
   R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  9: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  9: (62) *(u32 *)(r6 +0) = 0
   R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  10: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  10: (bf) r1 = r6
  11: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R1_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  11: (b7) r2 = 0
  12: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R1_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R2_w=invP0 R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
  12: (85) call bpf_ringbuf_submit#132
  13: R6=invP(id=0) R10=fp0 fp-8=mmmmmmmm
  13: (b7) r0 = 0
  14: R0_w=invP0 R6=invP(id=0) R10=fp0 fp-8=mmmmmmmm
  14: (95) exit

  from 8 to 13: safe
  processed 15 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 0
  OK

All three commits, that is b121b341e5 ("bpf: Add PTR_TO_BTF_ID_OR_NULL support"),
457f44363a ("bpf: Implement BPF ring buffer and verifier support for it"), and the
afbf21dce6 ("bpf: Support readonly/readwrite buffers in verifier") suffer the same
cause and their *_OR_NULL type pendants must be rejected in adjust_ptr_min_max_vals().

Make the test more robust by reusing reg_type_may_be_null() helper such that we catch
all *_OR_NULL types we have today and in future.

Note that pointer arithmetic on PTR_TO_BTF_ID, PTR_TO_RDONLY_BUF, and PTR_TO_RDWR_BUF
is generally allowed.

Fixes: b121b341e5 ("bpf: Add PTR_TO_BTF_ID_OR_NULL support")
Fixes: 457f44363a ("bpf: Implement BPF ring buffer and verifier support for it")
Fixes: afbf21dce6 ("bpf: Support readonly/readwrite buffers in verifier")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-16 09:14:22 +01:00
..
preload bpf: Fix umd memory leak in copy_process() 2021-03-30 14:32:03 +02:00
arraymap.c bpf: Fix potential race in tail call compatibility check 2021-11-02 19:48:21 +01:00
bpf_inode_storage.c bpf: Change inode_storage's lookup_elem return value from NULL to -EBADF 2021-03-30 14:31:56 +02:00
bpf_iter.c bpf: Fix an unitialized value in bpf_iter 2021-03-04 11:37:33 +01:00
bpf_local_storage.c bpf: Use hlist_add_head_rcu when linking to local_storage 2020-09-19 01:12:35 +02:00
bpf_lru_list.c bpf_lru_list: Read double-checked variable once without lock 2021-03-04 11:37:29 +01:00
bpf_lru_list.h bpf: Fix a typo "inacitve" -> "inactive" 2020-04-06 21:54:10 +02:00
bpf_lsm.c bpf: Update verification logic for LSM programs 2020-11-06 13:15:21 -08:00
bpf_struct_ops_types.h bpf: tcp: Support tcp_congestion_ops in bpf 2020-01-09 08:46:18 -08:00
bpf_struct_ops.c bpf: Handle return value of BPF_PROG_TYPE_STRUCT_OPS prog 2021-10-06 15:55:50 +02:00
btf.c bpf: Forbid trampoline attach for functions with variable arguments 2021-06-16 12:01:35 +02:00
cgroup.c bpf, cgroup: Fix problematic bounds check 2021-02-10 09:29:12 +01:00
core.c bpf: Prevent increasing bpf_jit_limit above max 2021-11-18 14:03:42 +01:00
cpumap.c bpf, cpumap: Remove rcpu pointer from cpu_map_build_skb signature 2020-09-28 23:30:42 +02:00
devmap.c bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc 2021-12-17 10:14:41 +01:00
disasm.c bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-08-04 12:46:44 +02:00
disasm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
dispatcher.c bpf: Remove bpf_image tree 2020-03-13 12:49:52 -07:00
hashtab.c bpf: Fix integer overflow involving bucket_size 2021-08-18 08:59:10 +02:00
helpers.c bpf: Fix potentially incorrect results with bpf_get_local_storage() 2021-09-03 10:09:31 +02:00
inode.c bpf: link: Refuse non-O_RDWR flags in BPF_OBJ_GET 2021-04-14 08:42:00 +02:00
local_storage.c bpf: Fix NULL pointer dereference in bpf_get_local_storage() helper 2021-09-03 10:09:21 +02:00
lpm_trie.c bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
Makefile bpf: Don't rely on GCC __attribute__((optimize)) to disable GCSE 2020-10-29 20:01:46 -07:00
map_in_map.c bpf: Relax max_entries check for most of the inner map types 2020-08-28 15:41:30 +02:00
map_in_map.h bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
map_iter.c bpf: Implement link_query callbacks in map element iterators 2020-08-21 14:01:39 -07:00
net_namespace.c bpf: Add support for forced LINK_DETACH command 2020-08-01 20:38:28 -07:00
offload.c bpf, offload: Replace bitwise AND by logical AND in bpf_prog_offload_info_fill 2020-02-17 16:53:49 +01:00
percpu_freelist.c bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI 2020-10-06 00:04:11 +02:00
percpu_freelist.h bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI 2020-10-06 00:04:11 +02:00
prog_iter.c bpf: Refactor bpf_iter_reg to have separate seq_info member 2020-07-25 20:16:32 -07:00
queue_stack_maps.c bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
reuseport_array.c bpf, net: Rework cookie generator as per-cpu one 2020-09-30 11:50:35 -07:00
ringbuf.c bpf: Fix false positive kmemleak report in bpf_ringbuf_area_alloc() 2021-07-19 09:44:54 +02:00
stackmap.c bpf: Fix integer overflow in prealloc_elems_and_freelist() 2021-10-13 10:04:26 +02:00
syscall.c bpf: Add kconfig knob for disabling unpriv bpf by default 2022-01-05 12:40:34 +01:00
sysfs_btf.c bpf: Fix sysfs export of empty BTF section 2020-09-21 21:50:24 +02:00
task_iter.c bpf: Save correct stopping point in file seq iteration 2021-01-19 18:27:28 +01:00
tnum.c bpf: Verifier, do explicit ALU32 bounds tracking 2020-03-30 14:59:53 -07:00
trampoline.c bpf: Fix fexit trampoline. 2021-04-07 15:00:03 +02:00
verifier.c bpf: Fix out of bounds access from invalid *_or_null type verification 2022-01-16 09:14:22 +01:00