Commit Graph

2616 Commits

Author SHA1 Message Date
Jordan Rome
82da3aedc9 bpf: Fix iter/task tid filtering
[ Upstream commit 9495a5b731fcaf580448a3438d63601c88367661 ]

In userspace, you can add a tid filter by setting
the "task.tid" field for "bpf_iter_link_info".
However, `get_pid_task` when called for the
`BPF_TASK_ITER_TID` type should have been using
`PIDTYPE_PID` (tid) instead of `PIDTYPE_TGID` (pid).

Fixes: f0d74c4da1 ("bpf: Parameterize task iterators.")
Signed-off-by: Jordan Rome <linux@jordanrome.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241016210048.1213935-1-linux@jordanrome.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-01 01:56:01 +01:00
Toke Høiland-Jørgensen
eb485fbdc2 bpf: fix kfunc btf caching for modules
[ Upstream commit 6cb86a0fdece87e126323ec1bb19deb16a52aedf ]

The verifier contains a cache for looking up module BTF objects when
calling kfuncs defined in modules. This cache uses a 'struct
bpf_kfunc_btf_tab', which contains a sorted list of BTF objects that
were already seen in the current verifier run, and the BTF objects are
looked up by the offset stored in the relocated call instruction using
bsearch().

The first time a given offset is seen, the module BTF is loaded from the
file descriptor passed in by libbpf, and stored into the cache. However,
there's a bug in the code storing the new entry: it stores a pointer to
the new cache entry, then calls sort() to keep the cache sorted for the
next lookup using bsearch(), and then returns the entry that was just
stored through the stored pointer. However, because sort() modifies the
list of entries in place *by value*, the stored pointer may no longer
point to the right entry, in which case the wrong BTF object will be
returned.

The end result of this is an intermittent bug where, if a BPF program
calls two functions with the same signature in two different modules,
the function from the wrong module may sometimes end up being called.
Whether this happens depends on the order of the calls in the BPF
program (as that affects whether sort() reorders the array of BTF
objects), making it especially hard to track down. Simon, credited as
reporter below, spent significant effort analysing and creating a
reproducer for this issue. The reproducer is added as a selftest in a
subsequent patch.

The fix is straight forward: simply don't use the stored pointer after
calling sort(). Since we already have an on-stack pointer to the BTF
object itself at the point where the function return, just use that, and
populate it from the cache entry in the branch where the lookup
succeeds.

Fixes: 2357672c54 ("bpf: Introduce BPF support for kernel module function calls")
Reported-by: Simon Sundberg <simon.sundberg@kau.se>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20241010-fix-kfunc-btf-caching-for-modules-v2-1-745af6c1af98@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-01 01:55:57 +01:00
Jiri Olsa
616e935d8a bpf: Fix memory leak in bpf_core_apply
[ Upstream commit 45126b155e3b5201179cdc038504bf93a8ccd921 ]

We need to free specs properly.

Fixes: 3d2786d65aaa ("bpf: correctly handle malformed BPF_CORE_TYPE_ID_LOCAL relos")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20241007160958.607434-1-jolsa@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-01 01:55:56 +01:00
Florian Kauer
a778fbe087 bpf: devmap: provide rxq after redirect
[ Upstream commit ca9984c5f0ab3690d98b13937b2485a978c8dd73 ]

rxq contains a pointer to the device from where
the redirect happened. Currently, the BPF program
that was executed after a redirect via BPF_MAP_TYPE_DEVMAP*
does not have it set.

This is particularly bad since accessing ingress_ifindex, e.g.

SEC("xdp")
int prog(struct xdp_md *pkt)
{
        return bpf_redirect_map(&dev_redirect_map, 0, 0);
}

SEC("xdp/devmap")
int prog_after_redirect(struct xdp_md *pkt)
{
        bpf_printk("ifindex %i", pkt->ingress_ifindex);
        return XDP_PASS;
}

depends on access to rxq, so a NULL pointer gets dereferenced:

<1>[  574.475170] BUG: kernel NULL pointer dereference, address: 0000000000000000
<1>[  574.475188] #PF: supervisor read access in kernel mode
<1>[  574.475194] #PF: error_code(0x0000) - not-present page
<6>[  574.475199] PGD 0 P4D 0
<4>[  574.475207] Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
<4>[  574.475217] CPU: 4 UID: 0 PID: 217 Comm: kworker/4:1 Not tainted 6.11.0-rc5-reduced-00859-g780801200300 #23
<4>[  574.475226] Hardware name: Intel(R) Client Systems NUC13ANHi7/NUC13ANBi7, BIOS ANRPL357.0026.2023.0314.1458 03/14/2023
<4>[  574.475231] Workqueue: mld mld_ifc_work
<4>[  574.475247] RIP: 0010:bpf_prog_5e13354d9cf5018a_prog_after_redirect+0x17/0x3c
<4>[  574.475257] Code: cc cc cc cc cc cc cc 80 00 00 00 cc cc cc cc cc cc cc cc f3 0f 1e fa 0f 1f 44 00 00 66 90 55 48 89 e5 f3 0f 1e fa 48 8b 57 20 <48> 8b 52 00 8b 92 e0 00 00 00 48 bf f8 a6 d5 c4 5d a0 ff ff be 0b
<4>[  574.475263] RSP: 0018:ffffa62440280c98 EFLAGS: 00010206
<4>[  574.475269] RAX: ffffa62440280cd8 RBX: 0000000000000001 RCX: 0000000000000000
<4>[  574.475274] RDX: 0000000000000000 RSI: ffffa62440549048 RDI: ffffa62440280ce0
<4>[  574.475278] RBP: ffffa62440280c98 R08: 0000000000000002 R09: 0000000000000001
<4>[  574.475281] R10: ffffa05dc8b98000 R11: ffffa05f577fca40 R12: ffffa05dcab24000
<4>[  574.475285] R13: ffffa62440280ce0 R14: ffffa62440549048 R15: ffffa62440549000
<4>[  574.475289] FS:  0000000000000000(0000) GS:ffffa05f4f700000(0000) knlGS:0000000000000000
<4>[  574.475294] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[  574.475298] CR2: 0000000000000000 CR3: 000000025522e000 CR4: 0000000000f50ef0
<4>[  574.475303] PKRU: 55555554
<4>[  574.475306] Call Trace:
<4>[  574.475313]  <IRQ>
<4>[  574.475318]  ? __die+0x23/0x70
<4>[  574.475329]  ? page_fault_oops+0x180/0x4c0
<4>[  574.475339]  ? skb_pp_cow_data+0x34c/0x490
<4>[  574.475346]  ? kmem_cache_free+0x257/0x280
<4>[  574.475357]  ? exc_page_fault+0x67/0x150
<4>[  574.475368]  ? asm_exc_page_fault+0x26/0x30
<4>[  574.475381]  ? bpf_prog_5e13354d9cf5018a_prog_after_redirect+0x17/0x3c
<4>[  574.475386]  bq_xmit_all+0x158/0x420
<4>[  574.475397]  __dev_flush+0x30/0x90
<4>[  574.475407]  veth_poll+0x216/0x250 [veth]
<4>[  574.475421]  __napi_poll+0x28/0x1c0
<4>[  574.475430]  net_rx_action+0x32d/0x3a0
<4>[  574.475441]  handle_softirqs+0xcb/0x2c0
<4>[  574.475451]  do_softirq+0x40/0x60
<4>[  574.475458]  </IRQ>
<4>[  574.475461]  <TASK>
<4>[  574.475464]  __local_bh_enable_ip+0x66/0x70
<4>[  574.475471]  __dev_queue_xmit+0x268/0xe40
<4>[  574.475480]  ? selinux_ip_postroute+0x213/0x420
<4>[  574.475491]  ? alloc_skb_with_frags+0x4a/0x1d0
<4>[  574.475502]  ip6_finish_output2+0x2be/0x640
<4>[  574.475512]  ? nf_hook_slow+0x42/0xf0
<4>[  574.475521]  ip6_finish_output+0x194/0x300
<4>[  574.475529]  ? __pfx_ip6_finish_output+0x10/0x10
<4>[  574.475538]  mld_sendpack+0x17c/0x240
<4>[  574.475548]  mld_ifc_work+0x192/0x410
<4>[  574.475557]  process_one_work+0x15d/0x380
<4>[  574.475566]  worker_thread+0x29d/0x3a0
<4>[  574.475573]  ? __pfx_worker_thread+0x10/0x10
<4>[  574.475580]  ? __pfx_worker_thread+0x10/0x10
<4>[  574.475587]  kthread+0xcd/0x100
<4>[  574.475597]  ? __pfx_kthread+0x10/0x10
<4>[  574.475606]  ret_from_fork+0x31/0x50
<4>[  574.475615]  ? __pfx_kthread+0x10/0x10
<4>[  574.475623]  ret_from_fork_asm+0x1a/0x30
<4>[  574.475635]  </TASK>
<4>[  574.475637] Modules linked in: veth br_netfilter bridge stp llc iwlmvm x86_pkg_temp_thermal iwlwifi efivarfs nvme nvme_core
<4>[  574.475662] CR2: 0000000000000000
<4>[  574.475668] ---[ end trace 0000000000000000 ]---

Therefore, provide it to the program by setting rxq properly.

Fixes: cb261b594b ("bpf: Run devmap xdp_prog on flush instead of bulk enqueue")
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Florian Kauer <florian.kauer@linutronix.de>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20240911-devel-koalo-fix-ingress-ifindex-v4-1-5c643ae10258@linutronix.de
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-01 01:55:56 +01:00
Wander Lairson Costa
5eb34999d1 bpf: Use raw_spinlock_t in ringbuf
[ Upstream commit 8b62645b09f870d70c7910e7550289d444239a46 ]

The function __bpf_ringbuf_reserve is invoked from a tracepoint, which
disables preemption. Using spinlock_t in this context can lead to a
"sleep in atomic" warning in the RT variant. This issue is illustrated
in the example below:

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 556208, name: test_progs
preempt_count: 1, expected: 0
RCU nest depth: 1, expected: 1
INFO: lockdep is turned off.
Preemption disabled at:
[<ffffd33a5c88ea44>] migrate_enable+0xc0/0x39c
CPU: 7 PID: 556208 Comm: test_progs Tainted: G
Hardware name: Qualcomm SA8775P Ride (DT)
Call trace:
 dump_backtrace+0xac/0x130
 show_stack+0x1c/0x30
 dump_stack_lvl+0xac/0xe8
 dump_stack+0x18/0x30
 __might_resched+0x3bc/0x4fc
 rt_spin_lock+0x8c/0x1a4
 __bpf_ringbuf_reserve+0xc4/0x254
 bpf_ringbuf_reserve_dynptr+0x5c/0xdc
 bpf_prog_ac3d15160d62622a_test_read_write+0x104/0x238
 trace_call_bpf+0x238/0x774
 perf_call_bpf_enter.isra.0+0x104/0x194
 perf_syscall_enter+0x2f8/0x510
 trace_sys_enter+0x39c/0x564
 syscall_trace_enter+0x220/0x3c0
 do_el0_svc+0x138/0x1dc
 el0_svc+0x54/0x130
 el0t_64_sync_handler+0x134/0x150
 el0t_64_sync+0x17c/0x180

Switch the spinlock to raw_spinlock_t to avoid this error.

Fixes: 457f44363a ("bpf: Implement BPF ring buffer and verifier support for it")
Reported-by: Brian Grech <bgrech@redhat.com>
Signed-off-by: Wander Lairson Costa <wander.lairson@gmail.com>
Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20240920190700.617253-1-wander@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-01 01:55:56 +01:00
Tao Chen
39b5ecc927 bpf: Check percpu map value size first
[ Upstream commit 1d244784be6b01162b732a5a7d637dfc024c3203 ]

Percpu map is often used, but the map value size limit often ignored,
like issue: https://github.com/iovisor/bcc/issues/2519. Actually,
percpu map value size is bound by PCPU_MIN_UNIT_SIZE, so we
can check the value size whether it exceeds PCPU_MIN_UNIT_SIZE first,
like percpu map of local_storage. Maybe the error message seems clearer
compared with "cannot allocate memory".

Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Tao Chen <chen.dylane@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240910144111.1464912-2-chen.dylane@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-17 15:22:12 +02:00
Daniel Borkmann
8397bf7898 bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error
[ Upstream commit 4b3786a6c5397dc220b1483d8e2f4867743e966f ]

For all non-tracing helpers which formerly had ARG_PTR_TO_{LONG,INT} as input
arguments, zero the value for the case of an error as otherwise it could leak
memory. For tracing, it is not needed given CAP_PERFMON can already read all
kernel memory anyway hence bpf_get_func_arg() and bpf_get_func_ret() is skipped
in here.

Also, the MTU helpers mtu_len pointer value is being written but also read.
Technically, the MEM_UNINIT should not be there in order to always force init.
Removing MEM_UNINIT needs more verifier rework though: MEM_UNINIT right now
implies two things actually: i) write into memory, ii) memory does not have
to be initialized. If we lift MEM_UNINIT, it then becomes: i) read into memory,
ii) memory must be initialized. This means that for bpf_*_check_mtu() we're
readding the issue we're trying to fix, that is, it would then be able to
write back into things like .rodata BPF maps. Follow-up work will rework the
MEM_UNINIT semantics such that the intent can be better expressed. For now
just clear the *mtu_len on error path which can be lifted later again.

Fixes: 8a67f2de9b ("bpf: expose bpf_strtol and bpf_strtoul to all program types")
Fixes: d7a4cb9b67 ("bpf: Introduce bpf_strtol and bpf_strtoul helpers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/e5edd241-59e7-5e39-0ee5-a51e31b6840a@iogearbox.net
Link: https://lore.kernel.org/r/20240913191754.13290-5-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-17 15:21:00 +02:00
Daniel Borkmann
81c602aa35 bpf: Improve check_raw_mode_ok test for MEM_UNINIT-tagged types
[ Upstream commit 18752d73c1898fd001569195ba4b0b8c43255f4a ]

When checking malformed helper function signatures, also take other argument
types into account aside from just ARG_PTR_TO_UNINIT_MEM.

This concerns (formerly) ARG_PTR_TO_{INT,LONG} given uninitialized memory can
be passed there, too.

The func proto sanity check goes back to commit 435faee1aa ("bpf, verifier:
add ARG_PTR_TO_RAW_STACK type"), and its purpose was to detect wrong func protos
which had more than just one MEM_UNINIT-tagged type as arguments.

The reason more than one is currently not supported is as we mark stack slots with
STACK_MISC in check_helper_call() in case of raw mode based on meta.access_size to
allow uninitialized stack memory to be passed to helpers when they just write into
the buffer.

Probing for base type as well as MEM_UNINIT tagging ensures that other types do not
get missed (as it used to be the case for ARG_PTR_TO_{INT,LONG}).

Fixes: 57c3bb725a ("bpf: Introduce ARG_PTR_TO_{INT,LONG} arg types")
Reported-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Link: https://lore.kernel.org/r/20240913191754.13290-4-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-17 15:21:00 +02:00
Daniel Borkmann
1782b0f0da bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit
[ Upstream commit cfe69c50b05510b24e26ccb427c7cc70beafd6c1 ]

The bpf_strtol() and bpf_strtoul() helpers are currently broken on 32bit:

The argument type ARG_PTR_TO_LONG is BPF-side "long", not kernel-side "long"
and therefore always considered fixed 64bit no matter if 64 or 32bit underlying
architecture.

This contract breaks in case of the two mentioned helpers since their BPF_CALL
definition for the helpers was added with {unsigned,}long *res. Meaning, the
transition from BPF-side "long" (BPF program) to kernel-side "long" (BPF helper)
breaks here.

Both helpers call __bpf_strtoll() with "long long" correctly, but later assigning
the result into 32-bit "*(long *)" on 32bit architectures. From a BPF program
point of view, this means upper bits will be seen as uninitialised.

Therefore, fix both BPF_CALL signatures to {s,u}64 types to fix this situation.

Now, changing also uapi/bpf.h helper documentation which generates bpf_helper_defs.h
for BPF programs is tricky: Changing signatures there to __{s,u}64 would trigger
compiler warnings (incompatible pointer types passing 'long *' to parameter of type
'__s64 *' (aka 'long long *')) for existing BPF programs.

Leaving the signatures as-is would be fine as from BPF program point of view it is
still BPF-side "long" and thus equivalent to __{s,u}64 on 64 or 32bit underlying
architectures.

Note that bpf_strtol() and bpf_strtoul() are the only helpers with this issue.

Fixes: d7a4cb9b67 ("bpf: Introduce bpf_strtol and bpf_strtoul helpers")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/481fcec8-c12c-9abb-8ecb-76c71c009959@iogearbox.net
Link: https://lore.kernel.org/r/20240913191754.13290-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-17 15:21:00 +02:00
Eduard Zingerman
dc7ce14f00 bpf: correctly handle malformed BPF_CORE_TYPE_ID_LOCAL relos
[ Upstream commit 3d2786d65aaa954ebd3fcc033ada433e10da21c4 ]

In case of malformed relocation record of kind BPF_CORE_TYPE_ID_LOCAL
referencing a non-existing BTF type, function bpf_core_calc_relo_insn
would cause a null pointer deference.

Fix this by adding a proper check upper in call stack, as malformed
relocation records could be passed from user space.

Simplest reproducer is a program:

    r0 = 0
    exit

With a single relocation record:

    .insn_off = 0,          /* patch first instruction */
    .type_id = 100500,      /* this type id does not exist */
    .access_str_off = 6,    /* offset of string "0" */
    .kind = BPF_CORE_TYPE_ID_LOCAL,

See the link for original reproducer or next commit for a test case.

Fixes: 74753e1462 ("libbpf: Replace btf__type_by_id() with btf_type_by_id().")
Reported-by: Liu RuiTong <cnitlrt@gmail.com>
Closes: https://lore.kernel.org/bpf/CAK55_s6do7C+DVwbwY_7nKfUz0YLDoiA1v6X3Y9+p0sWzipFSA@mail.gmail.com/
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240822080124.2995724-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-17 15:20:58 +02:00
Yonghong Song
61f4bd46a0 bpf: Silence a warning in btf_type_id_size()
commit e6c2f594ed961273479505b42040782820190305 upstream.

syzbot reported a warning in [1] with the following stacktrace:
  WARNING: CPU: 0 PID: 5005 at kernel/bpf/btf.c:1988 btf_type_id_size+0x2d9/0x9d0 kernel/bpf/btf.c:1988
  ...
  RIP: 0010:btf_type_id_size+0x2d9/0x9d0 kernel/bpf/btf.c:1988
  ...
  Call Trace:
   <TASK>
   map_check_btf kernel/bpf/syscall.c:1024 [inline]
   map_create+0x1157/0x1860 kernel/bpf/syscall.c:1198
   __sys_bpf+0x127f/0x5420 kernel/bpf/syscall.c:5040
   __do_sys_bpf kernel/bpf/syscall.c:5162 [inline]
   __se_sys_bpf kernel/bpf/syscall.c:5160 [inline]
   __x64_sys_bpf+0x79/0xc0 kernel/bpf/syscall.c:5160
   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
   do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
   entry_SYSCALL_64_after_hwframe+0x63/0xcd

With the following btf
  [1] DECL_TAG 'a' type_id=4 component_idx=-1
  [2] PTR '(anon)' type_id=0
  [3] TYPE_TAG 'a' type_id=2
  [4] VAR 'a' type_id=3, linkage=static
and when the bpf_attr.btf_key_type_id = 1 (DECL_TAG),
the following WARN_ON_ONCE in btf_type_id_size() is triggered:
  if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
                   !btf_type_is_var(size_type)))
          return NULL;

Note that 'return NULL' is the correct behavior as we don't want
a DECL_TAG type to be used as a btf_{key,value}_type_id even
for the case like 'DECL_TAG -> STRUCT'. So there
is no correctness issue here, we just want to silence warning.

To silence the warning, I added DECL_TAG as one of kinds in
btf_type_nosize() which will cause btf_type_id_size() returning
NULL earlier without the warning.

  [1] https://lore.kernel.org/bpf/000000000000e0df8d05fc75ba86@google.com/

Reported-by: syzbot+958967f249155967d42a@syzkaller.appspotmail.com
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230530205029.264910-1-yhs@fb.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-12 11:10:29 +02:00
Alexei Starovoitov
0fc3287d49 bpf: Avoid kfree_rcu() under lock in bpf_lpm_trie.
[ Upstream commit 59f2f841179aa6a0899cb9cf53659149a35749b7 ]

syzbot reported the following lock sequence:
cpu 2:
  grabs timer_base lock
    spins on bpf_lpm lock

cpu 1:
  grab rcu krcp lock
    spins on timer_base lock

cpu 0:
  grab bpf_lpm lock
    spins on rcu krcp lock

bpf_lpm lock can be the same.
timer_base lock can also be the same due to timer migration.
but rcu krcp lock is always per-cpu, so it cannot be the same lock.
Hence it's a false positive.
To avoid lockdep complaining move kfree_rcu() after spin_unlock.

Reported-by: syzbot+1fa663a2100308ab6eab@syzkaller.appspotmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240329171439.37813-1-alexei.starovoitov@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:30:22 +02:00
Kees Cook
d9a429fec7 bpf: Replace bpf_lpm_trie_key 0-length array with flexible array
[ Upstream commit 896880ff30866f386ebed14ab81ce1ad3710cfc4 ]

Replace deprecated 0-length array in struct bpf_lpm_trie_key with
flexible array. Found with GCC 13:

../kernel/bpf/lpm_trie.c:207:51: warning: array subscript i is outside array bounds of 'const __u8[0]' {aka 'const unsigned char[]'} [-Warray-bounds=]
  207 |                                        *(__be16 *)&key->data[i]);
      |                                                   ^~~~~~~~~~~~~
../include/uapi/linux/swab.h:102:54: note: in definition of macro '__swab16'
  102 | #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
      |                                                      ^
../include/linux/byteorder/generic.h:97:21: note: in expansion of macro '__be16_to_cpu'
   97 | #define be16_to_cpu __be16_to_cpu
      |                     ^~~~~~~~~~~~~
../kernel/bpf/lpm_trie.c:206:28: note: in expansion of macro 'be16_to_cpu'
  206 |                 u16 diff = be16_to_cpu(*(__be16 *)&node->data[i]
^
      |                            ^~~~~~~~~~~
In file included from ../include/linux/bpf.h:7:
../include/uapi/linux/bpf.h:82:17: note: while referencing 'data'
   82 |         __u8    data[0];        /* Arbitrary size */
      |                 ^~~~

And found at run-time under CONFIG_FORTIFY_SOURCE:

  UBSAN: array-index-out-of-bounds in kernel/bpf/lpm_trie.c:218:49
  index 0 is out of range for type '__u8 [*]'

Changing struct bpf_lpm_trie_key is difficult since has been used by
userspace. For example, in Cilium:

	struct egress_gw_policy_key {
	        struct bpf_lpm_trie_key lpm_key;
	        __u32 saddr;
	        __u32 daddr;
	};

While direct references to the "data" member haven't been found, there
are static initializers what include the final member. For example,
the "{}" here:

        struct egress_gw_policy_key in_key = {
                .lpm_key = { 32 + 24, {} },
                .saddr   = CLIENT_IP,
                .daddr   = EXTERNAL_SVC_IP & 0Xffffff,
        };

To avoid the build time and run time warnings seen with a 0-sized
trailing array for struct bpf_lpm_trie_key, introduce a new struct
that correctly uses a flexible array for the trailing bytes,
struct bpf_lpm_trie_key_u8. As part of this, include the "header"
portion (which is just the "prefixlen" member), so it can be used
by anything building a bpf_lpr_trie_key that has trailing members that
aren't a u8 flexible array (like the self-test[1]), which is named
struct bpf_lpm_trie_key_hdr.

Unfortunately, C++ refuses to parse the __struct_group() helper, so
it is not possible to define struct bpf_lpm_trie_key_hdr directly in
struct bpf_lpm_trie_key_u8, so we must open-code the union directly.

Adjust the kernel code to use struct bpf_lpm_trie_key_u8 through-out,
and for the selftest to use struct bpf_lpm_trie_key_hdr. Add a comment
to the UAPI header directing folks to the two new options.

Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Closes: https://paste.debian.net/hidden/ca500597/
Link: https://lore.kernel.org/all/202206281009.4332AA33@keescook/ [1]
Link: https://lore.kernel.org/bpf/20240222155612.it.533-kees@kernel.org
Stable-dep-of: 59f2f841179a ("bpf: Avoid kfree_rcu() under lock in bpf_lpm_trie.")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:30:22 +02:00
Andrii Nakryiko
40c88c429a bpf: drop unnecessary user-triggerable WARN_ONCE in verifierl log
[ Upstream commit cff36398bd4c7d322d424433db437f3c3391c491 ]

It's trivial for user to trigger "verifier log line truncated" warning,
as verifier has a fixed-sized buffer of 1024 bytes (as of now), and there are at
least two pieces of user-provided information that can be output through
this buffer, and both can be arbitrarily sized by user:
  - BTF names;
  - BTF.ext source code lines strings.

Verifier log buffer should be properly sized for typical verifier state
output. But it's sort-of expected that this buffer won't be long enough
in some circumstances. So let's drop the check. In any case code will
work correctly, at worst truncating a part of a single line output.

Reported-by: syzbot+8b2a08dfbd25fd933d75@syzkaller.appspotmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230516180409.3549088-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:30:17 +02:00
Andrii Nakryiko
3551cd065a bpf: Split off basic BPF verifier log into separate file
[ Upstream commit 4294a0a7ab6282c3d92f03de84e762dda993c93d ]

kernel/bpf/verifier.c file is large and growing larger all the time. So
it's good to start splitting off more or less self-contained parts into
separate files to keep source code size (somewhat) somewhat under
control.

This patch is a one step in this direction, moving some of BPF verifier log
routines into a separate kernel/bpf/log.c. Right now it's most low-level
and isolated routines to append data to log, reset log to previous
position, etc. Eventually we could probably move verifier state
printing logic here as well, but this patch doesn't attempt to do that
yet.

Subsequent patches will add more logic to verifier log management, so
having basics in a separate file will make sure verifier.c doesn't grow
more with new changes.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-2-andrii@kernel.org
Stable-dep-of: cff36398bd4c ("bpf: drop unnecessary user-triggerable WARN_ONCE in verifierl log")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:30:17 +02:00
Jiri Olsa
d0d2df38f5 bpf: Synchronize dispatcher update with bpf_dispatcher_xdp_func
commit 4121d4481b72501aa4d22680be4ea1096d69d133 upstream.

Hao Sun reported crash in dispatcher image [1].

Currently we don't have any sync between bpf_dispatcher_update and
bpf_dispatcher_xdp_func, so following race is possible:

 cpu 0:                               cpu 1:

 bpf_prog_run_xdp
   ...
   bpf_dispatcher_xdp_func
     in image at offset 0x0

                                      bpf_dispatcher_update
                                        update image at offset 0x800
                                      bpf_dispatcher_update
                                        update image at offset 0x0

     in image at offset 0x0 -> crash

Fixing this by synchronizing dispatcher image update (which is done
in bpf_dispatcher_update function) with bpf_dispatcher_xdp_func that
reads and execute the dispatcher image.

Calling synchronize_rcu after updating and installing new image ensures
that readers leave old image before it's changed in the next dispatcher
update. The update itself is locked with dispatcher's mutex.

The bpf_prog_run_xdp is called under local_bh_disable and synchronize_rcu
will wait for it to leave [2].

[1] https://lore.kernel.org/bpf/Y5SFho7ZYXr9ifRn@krava/T/#m00c29ece654bc9f332a17df493bbca33e702896c
[2] https://lore.kernel.org/bpf/0B62D35A-E695-4B7A-A0D4-774767544C1A@gmail.com/T/#mff43e2c003ae99f4a38f353c7969be4c7162e877

Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20221214123542.1389719-1-jolsa@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reported-by: syzbot+08ba1e474d350b613604@syzkaller.appspotmail.com
Signed-off-by: Sergio González Collado <sergio.collado@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-03 08:49:45 +02:00
Alan Maguire
70f9365a8f bpf: Eliminate remaining "make W=1" warnings in kernel/bpf/btf.o
[ Upstream commit 2454075f8e2915cebbe52a1195631bc7efe2b7e1 ]

As reported by Mirsad [1] we still see format warnings in kernel/bpf/btf.o
at W=1 warning level:

  CC      kernel/bpf/btf.o
./kernel/bpf/btf.c: In function ‘btf_type_seq_show_flags’:
./kernel/bpf/btf.c:7553:21: warning: assignment left-hand side might be a candidate for a format attribute [-Wsuggest-attribute=format]
 7553 |         sseq.showfn = btf_seq_show;
      |                     ^
./kernel/bpf/btf.c: In function ‘btf_type_snprintf_show’:
./kernel/bpf/btf.c:7604:31: warning: assignment left-hand side might be a candidate for a format attribute [-Wsuggest-attribute=format]
 7604 |         ssnprintf.show.showfn = btf_snprintf_show;
      |                               ^

Combined with CONFIG_WERROR=y these can halt the build.

The fix (annotating the structure field with __printf())
suggested by Mirsad resolves these. Apologies I missed this last time.
No other W=1 warnings were observed in kernel/bpf after this fix.

[1] https://lore.kernel.org/bpf/92c9d047-f058-400c-9c7d-81d4dc1ef71b@gmail.com/

Fixes: b3470da314fd ("bpf: annotate BTF show functions with __printf")
Reported-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Suggested-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240712092859.1390960-1-alan.maguire@oracle.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03 08:49:09 +02:00
Alan Maguire
9dfbfd4f31 bpf: annotate BTF show functions with __printf
[ Upstream commit b3470da314fd8018ee237e382000c4154a942420 ]

-Werror=suggest-attribute=format warns about two functions
in kernel/bpf/btf.c [1]; add __printf() annotations to silence
these warnings since for CONFIG_WERROR=y they will trigger
build failures.

[1] https://lore.kernel.org/bpf/a8b20c72-6631-4404-9e1f-0410642d7d20@gmail.com/

Fixes: 31d0bc8163 ("bpf: Move to generic BTF show support, apply it to seq files/strings")
Reported-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Mirsad Todorovac <mtodorovac69@yahoo.com>
Link: https://lore.kernel.org/r/20240711182321.963667-1-alan.maguire@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03 08:49:08 +02:00
Eduard Zingerman
bbac91d57a bpf: Allow reads from uninit stack
commit 6715df8d5d24655b9fd368e904028112b54c7de1 upstream.

This commits updates the following functions to allow reads from
uninitialized stack locations when env->allow_uninit_stack option is
enabled:
- check_stack_read_fixed_off()
- check_stack_range_initialized(), called from:
  - check_stack_read_var_off()
  - check_helper_mem_access()

Such change allows to relax logic in stacksafe() to treat STACK_MISC
and STACK_INVALID in a same way and make the following stack slot
configurations equivalent:

  |  Cached state    |  Current state   |
  |   stack slot     |   stack slot     |
  |------------------+------------------|
  | STACK_INVALID or | STACK_INVALID or |
  | STACK_MISC       | STACK_SPILL   or |
  |                  | STACK_MISC    or |
  |                  | STACK_ZERO    or |
  |                  | STACK_DYNPTR     |

This leads to significant verification speed gains (see below).

The idea was suggested by Andrii Nakryiko [1] and initial patch was
created by Alexei Starovoitov [2].

Currently the env->allow_uninit_stack is allowed for programs loaded
by users with CAP_PERFMON or CAP_SYS_ADMIN capabilities.

A number of test cases from verifier/*.c were expecting uninitialized
stack access to be an error. These test cases were updated to execute
in unprivileged mode (thus preserving the tests).

The test progs/test_global_func10.c expected "invalid indirect read
from stack" error message because of the access to uninitialized
memory region. This error is no longer possible in privileged mode.
The test is updated to provoke an error "invalid indirect access to
stack" because of access to invalid stack address (such error is not
verified by progs/test_global_func*.c series of tests).

The following tests had to be removed because these can't be made
unprivileged:
- verifier/sock.c:
  - "sk_storage_get(map, skb->sk, &stack_value, 1): partially init
  stack_value"
  BPF_PROG_TYPE_SCHED_CLS programs are not executed in unprivileged mode.
- verifier/var_off.c:
  - "indirect variable-offset stack access, max_off+size > max_initialized"
  - "indirect variable-offset stack access, uninitialized"
  These tests verify that access to uninitialized stack values is
  detected when stack offset is not a constant. However, variable
  stack access is prohibited in unprivileged mode, thus these tests
  are no longer valid.

 * * *

Here is veristat log comparing this patch with current master on a
set of selftest binaries listed in tools/testing/selftests/bpf/veristat.cfg
and cilium BPF binaries (see [3]):

$ ./veristat -e file,prog,states -C -f 'states_pct<-30' master.log current.log
File                        Program                     States (A)  States (B)  States    (DIFF)
--------------------------  --------------------------  ----------  ----------  ----------------
bpf_host.o                  tail_handle_ipv6_from_host         349         244    -105 (-30.09%)
bpf_host.o                  tail_handle_nat_fwd_ipv4          1320         895    -425 (-32.20%)
bpf_lxc.o                   tail_handle_nat_fwd_ipv4          1320         895    -425 (-32.20%)
bpf_sock.o                  cil_sock4_connect                   70          48     -22 (-31.43%)
bpf_sock.o                  cil_sock4_sendmsg                   68          46     -22 (-32.35%)
bpf_xdp.o                   tail_handle_nat_fwd_ipv4          1554         803    -751 (-48.33%)
bpf_xdp.o                   tail_lb_ipv4                      6457        2473   -3984 (-61.70%)
bpf_xdp.o                   tail_lb_ipv6                      7249        3908   -3341 (-46.09%)
pyperf600_bpf_loop.bpf.o    on_event                           287         145    -142 (-49.48%)
strobemeta.bpf.o            on_event                         15915        4772  -11143 (-70.02%)
strobemeta_nounroll2.bpf.o  on_event                         17087        3820  -13267 (-77.64%)
xdp_synproxy_kern.bpf.o     syncookie_tc                     21271        6635  -14636 (-68.81%)
xdp_synproxy_kern.bpf.o     syncookie_xdp                    23122        6024  -17098 (-73.95%)
--------------------------  --------------------------  ----------  ----------  ----------------

Note: I limited selection by states_pct<-30%.

Inspection of differences in pyperf600_bpf_loop behavior shows that
the following patch for the test removes almost all differences:

    - a/tools/testing/selftests/bpf/progs/pyperf.h
    + b/tools/testing/selftests/bpf/progs/pyperf.h
    @ -266,8 +266,8 @ int __on_event(struct bpf_raw_tracepoint_args *ctx)
            }

            if (event->pthread_match || !pidData->use_tls) {
    -               void* frame_ptr;
    -               FrameData frame;
    +               void* frame_ptr = 0;
    +               FrameData frame = {};
                    Symbol sym = {};
                    int cur_cpu = bpf_get_smp_processor_id();

W/o this patch the difference comes from the following pattern
(for different variables):

    static bool get_frame_data(... FrameData *frame ...)
    {
        ...
        bpf_probe_read_user(&frame->f_code, ...);
        if (!frame->f_code)
            return false;
        ...
        bpf_probe_read_user(&frame->co_name, ...);
        if (frame->co_name)
            ...;
    }

    int __on_event(struct bpf_raw_tracepoint_args *ctx)
    {
        FrameData frame;
        ...
        get_frame_data(... &frame ...) // indirectly via a bpf_loop & callback
        ...
    }

    SEC("raw_tracepoint/kfree_skb")
    int on_event(struct bpf_raw_tracepoint_args* ctx)
    {
        ...
        ret |= __on_event(ctx);
        ret |= __on_event(ctx);
        ...
    }

With regards to value `frame->co_name` the following is important:
- Because of the conditional `if (!frame->f_code)` each call to
  __on_event() produces two states, one with `frame->co_name` marked
  as STACK_MISC, another with it as is (and marked STACK_INVALID on a
  first call).
- The call to bpf_probe_read_user() does not mark stack slots
  corresponding to `&frame->co_name` as REG_LIVE_WRITTEN but it marks
  these slots as BPF_MISC, this happens because of the following loop
  in the check_helper_call():

	for (i = 0; i < meta.access_size; i++) {
		err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
				       BPF_WRITE, -1, false);
		if (err)
			return err;
	}

  Note the size of the write, it is a one byte write for each byte
  touched by a helper. The BPF_B write does not lead to write marks
  for the target stack slot.
- Which means that w/o this patch when second __on_event() call is
  verified `if (frame->co_name)` will propagate read marks first to a
  stack slot with STACK_MISC marks and second to a stack slot with
  STACK_INVALID marks and these states would be considered different.

[1] https://lore.kernel.org/bpf/CAEf4BzY3e+ZuC6HUa8dCiUovQRg2SzEk7M-dSkqNZyn=xEmnPA@mail.gmail.com/
[2] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/
[3] git@github.com:anakryiko/cilium.git

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Co-developed-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230219200427.606541-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-18 13:18:42 +02:00
Mohammad Shehar Yaar Tausif
6c4fca7864 bpf: fix order of args in call to bpf_map_kvcalloc
[ Upstream commit af253aef183a31ce62d2e39fc520b0ebfb562bb9 ]

The original function call passed size of smap->bucket before the number of
buckets which raises the error 'calloc-transposed-args' on compilation.

Vlastimil Babka added:

The order of parameters can be traced back all the way to 6ac99e8f23
("bpf: Introduce bpf sk local storage") accross several refactorings,
and that's why the commit is used as a Fixes: tag.

In v6.10-rc1, a different commit 2c321f3f70bc ("mm: change inlined
allocation helpers to account at the call site") however exposed the
order of args in a way that gcc-14 has enough visibility to start
warning about it, because (in !CONFIG_MEMCG case) bpf_map_kvcalloc is
then a macro alias for kvcalloc instead of a static inline wrapper.

To sum up the warning happens when the following conditions are all met:

- gcc-14 is used (didn't see it with gcc-13)
- commit 2c321f3f70bc is present
- CONFIG_MEMCG is not enabled in .config
- CONFIG_WERROR turns this from a compiler warning to error

Fixes: 6ac99e8f23 ("bpf: Introduce bpf sk local storage")
Reviewed-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Mohammad Shehar Yaar Tausif <sheharyaar48@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/20240710100521.15061-2-vbabka@suse.cz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:18:34 +02:00
Martin KaFai Lau
d71bed34bc bpf: Remove __bpf_local_storage_map_alloc
[ Upstream commit 62827d612ae525695799b3635a087cb49c55e977 ]

bpf_local_storage_map_alloc() is the only caller of
__bpf_local_storage_map_alloc().  The remaining logic in
bpf_local_storage_map_alloc() is only a one liner setting
the smap->cache_idx.

Remove __bpf_local_storage_map_alloc() to simplify code.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: af253aef183a ("bpf: fix order of args in call to bpf_map_kvcalloc")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:18:34 +02:00
Yafang Shao
902219ed3f bpf: use bpf_map_kvcalloc in bpf_local_storage
[ Upstream commit ddef81b5fd1da4d7c3cc8785d2043b73b72f38ef ]

Introduce new helper bpf_map_kvcalloc() for the memory allocation in
bpf_local_storage(). Then the allocation will charge the memory from the
map instead of from current, though currently they are the same thing as
it is only used in map creation path now. By charging map's memory into
the memcg from the map, it will be more clear.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: af253aef183a ("bpf: fix order of args in call to bpf_map_kvcalloc")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:18:34 +02:00
Martin KaFai Lau
56161b324b bpf: Reduce smap->elem_size
[ Upstream commit 552d42a356ebf78df9d2f4b73e077d2459966fac ]

'struct bpf_local_storage_elem' has an unused 56 byte padding at the
end due to struct's cache-line alignment requirement. This padding
space is overlapped by storage value contents, so if we use sizeof()
to calculate the total size, we overinflate it by 56 bytes. Use
offsetof() instead to calculate more exact memory use.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221221013036.3427431-1-martin.lau@linux.dev
Stable-dep-of: af253aef183a ("bpf: fix order of args in call to bpf_map_kvcalloc")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:18:34 +02:00
Yonghong Song
3dbcc6f053 bpf: Refactor some inode/task/sk storage functions for reuse
[ Upstream commit c83597fa5dc6b322e9bdf929e5f4136a3f4aa4db ]

Refactor codes so that inode/task/sk storage implementation
can maximally share the same code. I also added some comments
in new function bpf_local_storage_unlink_nolock() to make
codes easy to understand. There is no functionality change.

Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221026042845.672944-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: af253aef183a ("bpf: fix order of args in call to bpf_map_kvcalloc")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:18:34 +02:00
Martin KaFai Lau
b30f3197a6 bpf: Mark bpf prog stack with kmsan_unposion_memory in interpreter mode
[ Upstream commit e8742081db7d01f980c6161ae1e8a1dbc1e30979 ]

syzbot reported uninit memory usages during map_{lookup,delete}_elem.

==========
BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
__dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
__bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237
==========

The reproducer should be in the interpreter mode.

The C reproducer is trying to run the following bpf prog:

    0: (18) r0 = 0x0
    2: (18) r1 = map[id:49]
    4: (b7) r8 = 16777216
    5: (7b) *(u64 *)(r10 -8) = r8
    6: (bf) r2 = r10
    7: (07) r2 += -229
            ^^^^^^^^^^

    8: (b7) r3 = 8
    9: (b7) r4 = 0
   10: (85) call dev_map_lookup_elem#1543472
   11: (95) exit

It is due to the "void *key" (r2) passed to the helper. bpf allows uninit
stack memory access for bpf prog with the right privileges. This patch
uses kmsan_unpoison_memory() to mark the stack as initialized.

This should address different syzbot reports on the uninit "void *key"
argument during map_{lookup,delete}_elem.

Reported-by: syzbot+603bcd9b0bf1d94dbb9b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000f9ce6d061494e694@google.com/
Reported-by: syzbot+eb02dc7f03dce0ef39f3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000a5c69c06147c2238@google.com/
Reported-by: syzbot+b4e65ca24fd4d0c734c3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000ac56fb06143b6cfa@google.com/
Reported-by: syzbot+d2b113dc9fea5e1d2848@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/0000000000000d69b206142d1ff7@google.com/
Reported-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/0000000000006f876b061478e878@google.com/
Tested-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com
Suggested-by: Yonghong Song <yonghong.song@linux.dev>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240328185801.1843078-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05 09:31:48 +02:00