Do not use rlimit-based memory accounting for bpf ringbuffer.
It has been replaced with the memcg-based memory accounting.
bpf_ringbuf_alloc() can't return anything except ERR_PTR(-ENOMEM)
and a valid pointer, so to simplify the code make it return NULL
in the first case. This allows to drop a couple of lines in
ringbuf_map_alloc() and also makes it look similar to other memory
allocating function like kmalloc().
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-28-guro@fb.com
This patch enables memcg-based memory accounting for memory allocated
by __bpf_map_area_alloc(), which is used by many types of bpf maps for
large initial memory allocations.
Please note, that __bpf_map_area_alloc() should not be used outside of
map creation paths without setting the active memory cgroup to the
map's memory cgroup.
Following patches in the series will refine the accounting for
some of the map types.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-8-guro@fb.com
Bpf maps can be updated from an interrupt context and in such
case there is no process which can be charged. It makes the memory
accounting of bpf maps non-trivial.
Fortunately, after commit 4127c6504f ("mm: kmem: enable kernel
memcg accounting from interrupt contexts") and commit b87d8cefe4
("mm, memcg: rework remote charging API to support nesting")
it's finally possible.
To make the ownership model simple and consistent, when the map
is created, the memory cgroup of the current process is recorded.
All subsequent allocations related to the bpf map are charged to
the same memory cgroup. It includes allocations made by any processes
(even if they do belong to a different cgroup) and from interrupts.
This commit introduces 3 new helpers, which will be used by following
commits to enable the accounting of bpf maps memory:
- bpf_map_kmalloc_node()
- bpf_map_kzalloc()
- bpf_map_alloc_percpu()
They are wrapping popular memory allocation functions. They set
the active memory cgroup to the map's memory cgroup and add
__GFP_ACCOUNT to the passed gfp flags. Then they call into
the corresponding memory allocation function and restore
the original active memory cgroup.
These helpers are supposed to use everywhere except the map creation
path. During the map creation when the map structure is allocated by
itself, it cannot be passed to those helpers. In those cases default
memory allocation function will be used with the __GFP_ACCOUNT flag.
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-7-guro@fb.com
Include memory used by bpf programs into the memcg-based accounting.
This includes the memory used by programs itself, auxiliary data,
statistics and bpf line info. A memory cgroup containing the
process which loads the program is getting charged.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-6-guro@fb.com
Provide a wrapper function to get the IMA hash of an inode. This helper
is useful in fingerprinting files (e.g executables on execution) and
using these fingerprints in detections like an executable unlinking
itself.
Since the ima_inode_hash can sleep, it's only allowed for sleepable
LSM hooks.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20201124151210.1081188-3-kpsingh@chromium.org
The current implementation uses a number of gotos to implement a loop
and different paths within the loop, which makes the code less readable
than it would be with an explicit while-loop. This patch also replaces a
chain of if/if-elses keyed on the same expression with a switch
statement.
No change in behaviour is intended.
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201121015509.3594191-1-wedsonaf@google.com
Get rid of the __call_single_node union and clean up the API a little
to avoid external code relying on the structure layout as much.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
The helper uses CLOCK_MONOTONIC_COARSE source of time that is less
accurate but more performant.
We have a BPF CGROUP_SKB firewall that supports event logging through
bpf_perf_event_output(). Each event has a timestamp and currently we use
bpf_ktime_get_ns() for it. Use of bpf_ktime_get_coarse_ns() saves ~15-20
ns in time required for event logging.
bpf_ktime_get_ns():
EgressLogByRemoteEndpoint 113.82ns 8.79M
bpf_ktime_get_coarse_ns():
EgressLogByRemoteEndpoint 95.40ns 10.48M
Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201117184549.257280-1-me@ubique.spb.ru
The helper allows modification of certain bits on the linux_binprm
struct starting with the secureexec bit which can be updated using the
BPF_F_BPRM_SECUREEXEC flag.
secureexec can be set by the LSM for privilege gaining executions to set
the AT_SECURE auxv for glibc. When set, the dynamic linker disables the
use of certain environment variables (like LD_PRELOAD).
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201117232929.2156341-1-kpsingh@chromium.org
Daniel Borkmann says:
====================
pull-request: bpf-next 2020-11-14
1) Add BTF generation for kernel modules and extend BTF infra in kernel
e.g. support for split BTF loading and validation, from Andrii Nakryiko.
2) Support for pointers beyond pkt_end to recognize LLVM generated patterns
on inlined branch conditions, from Alexei Starovoitov.
3) Implements bpf_local_storage for task_struct for BPF LSM, from KP Singh.
4) Enable FENTRY/FEXIT/RAW_TP tracing program to use the bpf_sk_storage
infra, from Martin KaFai Lau.
5) Add XDP bulk APIs that introduce a defer/flush mechanism to optimize the
XDP_REDIRECT path, from Lorenzo Bianconi.
6) Fix a potential (although rather theoretical) deadlock of hashtab in NMI
context, from Song Liu.
7) Fixes for cross and out-of-tree build of bpftool and runqslower allowing build
for different target archs on same source tree, from Jean-Philippe Brucker.
8) Fix error path in htab_map_alloc() triggered from syzbot, from Eric Dumazet.
9) Move functionality from test_tcpbpf_user into the test_progs framework so it
can run in BPF CI, from Alexander Duyck.
10) Lift hashtab key_size limit to be larger than MAX_BPF_STACK, from Florian Lehner.
Note that for the fix from Song we have seen a sparse report on context
imbalance which requires changes in sparse itself for proper annotation
detection where this is currently being discussed on linux-sparse among
developers [0]. Once we have more clarification/guidance after their fix,
Song will follow-up.
[0] https://lore.kernel.org/linux-sparse/CAHk-=wh4bx8A8dHnX612MsDO13st6uzAz1mJ1PaHHVevJx_ZCw@mail.gmail.com/T/https://lore.kernel.org/linux-sparse/20201109221345.uklbp3lzgq6g42zb@ltop.local/T/
* git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (66 commits)
net: mlx5: Add xdp tx return bulking support
net: mvpp2: Add xdp tx return bulking support
net: mvneta: Add xdp tx return bulking support
net: page_pool: Add bulk support for ptr_ring
net: xdp: Introduce bulking for xdp tx return path
bpf: Expose bpf_d_path helper to sleepable LSM hooks
bpf: Augment the set of sleepable LSM hooks
bpf: selftest: Use bpf_sk_storage in FENTRY/FEXIT/RAW_TP
bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP
bpf: Rename some functions in bpf_sk_storage
bpf: Folding omem_charge() into sk_storage_charge()
selftests/bpf: Add asm tests for pkt vs pkt_end comparison.
selftests/bpf: Add skb_pkt_end test
bpf: Support for pointers beyond pkt_end.
tools/bpf: Always run the *-clean recipes
tools/bpf: Add bootstrap/ to .gitignore
bpf: Fix NULL dereference in bpf_task_storage
tools/bpftool: Fix build slowdown
tools/runqslower: Build bpftool using HOSTCC
tools/runqslower: Enable out-of-tree build
...
====================
Link: https://lore.kernel.org/r/20201114020819.29584-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently verifier enforces return code checks for subprograms in the
same manner as it does for program entry points. This prevents returning
arbitrary scalar values from subprograms. Scalar type of returned values
is checked by btf_prepare_func_args() and hence it should be safe to
allow only scalars for now. Relax return code checks for subprograms and
allow any correct scalar values.
Fixes: 51c39bb1d5 (bpf: Introduce function-by-function verification)
Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201113171756.90594-1-me@ubique.spb.ru
Update the set of sleepable hooks with the ones that do not trigger
a warning with might_fault() when exercised with the correct kernel
config options enabled, i.e.
DEBUG_ATOMIC_SLEEP=y
LOCKDEP=y
PROVE_LOCKING=y
This means that a sleepable LSM eBPF program can be attached to these
LSM hooks. A new helper method bpf_lsm_is_sleepable_hook is added and
the set is maintained locally in bpf_lsm.c
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201113005930.541956-2-kpsingh@chromium.org
This patch adds the verifier support to recognize inlined branch conditions.
The LLVM knows that the branch evaluates to the same value, but the verifier
couldn't track it. Hence causing valid programs to be rejected.
The potential LLVM workaround: https://reviews.llvm.org/D87428
can have undesired side effects, since LLVM doesn't know that
skb->data/data_end are being compared. LLVM has to introduce extra boolean
variable and use inline_asm trick to force easier for the verifier assembly.
Instead teach the verifier to recognize that
r1 = skb->data;
r1 += 10;
r2 = skb->data_end;
if (r1 > r2) {
here r1 points beyond packet_end and
subsequent
if (r1 > r2) // always evaluates to "true".
}
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20201111031213.25109-2-alexei.starovoitov@gmail.com
Add kernel module listener that will load/validate and unload module BTF.
Module BTFs gets ID generated for them, which makes it possible to iterate
them with existing BTF iteration API. They are given their respective module's
names, which will get reported through GET_OBJ_INFO API. They are also marked
as in-kernel BTFs for tooling to distinguish them from user-provided BTFs.
Also, similarly to vmlinux BTF, kernel module BTFs are exposed through
sysfs as /sys/kernel/btf/<module-name>. This is convenient for user-space
tools to inspect module BTF contents and dump their types with existing tools:
[vmuser@archvm bpf]$ ls -la /sys/kernel/btf
total 0
drwxr-xr-x 2 root root 0 Nov 4 19:46 .
drwxr-xr-x 13 root root 0 Nov 4 19:46 ..
...
-r--r--r-- 1 root root 888 Nov 4 19:46 irqbypass
-r--r--r-- 1 root root 100225 Nov 4 19:46 kvm
-r--r--r-- 1 root root 35401 Nov 4 19:46 kvm_intel
-r--r--r-- 1 root root 120 Nov 4 19:46 pcspkr
-r--r--r-- 1 root root 399 Nov 4 19:46 serio_raw
-r--r--r-- 1 root root 4094095 Nov 4 19:46 vmlinux
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/bpf/20201110011932.3201430-5-andrii@kernel.org
Allocate ID for vmlinux BTF. This makes it visible when iterating over all BTF
objects in the system. To allow distinguishing vmlinux BTF (and later kernel
module BTF) from user-provided BTFs, expose extra kernel_btf flag, as well as
BTF name ("vmlinux" for vmlinux BTF, will equal to module's name for module
BTF). We might want to later allow specifying BTF name for user-provided BTFs
as well, if that makes sense. But currently this is reserved only for
in-kernel BTFs.
Having in-kernel BTFs exposed IDs will allow to extend BPF APIs that require
in-kernel BTF type with ability to specify BTF types from kernel modules, not
just vmlinux BTF. This will be implemented in a follow up patch set for
fentry/fexit/fmod_ret/lsm/etc.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201110011932.3201430-3-andrii@kernel.org
Adjust in-kernel BTF implementation to support a split BTF mode of operation.
Changes are mostly mirroring libbpf split BTF changes, with the exception of
start_id being 0 for in-kernel implementation due to simpler read-only mode.
Otherwise, for split BTF logic, most of the logic of jumping to base BTF,
where necessary, is encapsulated in few helper functions. Type numbering and
string offset in a split BTF are logically continuing where base BTF ends, so
most of the high-level logic is kept without changes.
Type verification and size resolution is only doing an added resolution of new
split BTF types and relies on already cached size and type resolution results
in the base BTF.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201110011932.3201430-2-andrii@kernel.org
The current logic checks if the name of the BTF type passed in
attach_btf_id starts with "bpf_lsm_", this is not sufficient as it also
allows attachment to non-LSM hooks like the very function that performs
this check, i.e. bpf_lsm_verify_prog.
In order to ensure that this verification logic allows attachment to
only LSM hooks, the LSM_HOOK definitions in lsm_hook_defs.h are used to
generate a BTF_ID set. Upon verification, the attach_btf_id of the
program being attached is checked for presence in this set.
Fixes: 9e4e01dfd3 ("bpf: lsm: Implement attach, detach and execution")
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201105230651.2621917-1-kpsingh@chromium.org
The currently available bpf_get_current_task returns an unsigned integer
which can be used along with BPF_CORE_READ to read data from
the task_struct but still cannot be used as an input argument to a
helper that accepts an ARG_PTR_TO_BTF_ID of type task_struct.
In order to implement this helper a new return type, RET_PTR_TO_BTF_ID,
is added. This is similar to RET_PTR_TO_BTF_ID_OR_NULL but does not
require checking the nullness of returned pointer.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201106103747.2780972-6-kpsingh@chromium.org
Similar to bpf_local_storage for sockets and inodes add local storage
for task_struct.
The life-cycle of storage is managed with the life-cycle of the
task_struct. i.e. the storage is destroyed along with the owning task
with a callback to the bpf_task_storage_free from the task_free LSM
hook.
The BPF LSM allocates an __rcu pointer to the bpf_local_storage in
the security blob which are now stackable and can co-exist with other
LSMs.
The userspace map operations can be done by using a pid fd as a key
passed to the lookup, update and delete operations.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201106103747.2780972-3-kpsingh@chromium.org
Currently key_size of hashtab is limited to MAX_BPF_STACK.
As the key of hashtab can also be a value from a per cpu map it can be
larger than MAX_BPF_STACK.
The use-case for this patch originates to implement allow/disallow
lists for files and file paths. The maximum length of file paths is
defined by PATH_MAX with 4096 chars including nul.
This limit exceeds MAX_BPF_STACK.
Changelog:
v5:
- Fix cast overflow
v4:
- Utilize BPF skeleton in tests
- Rebase
v3:
- Rebase
v2:
- Add a test for bpf side
Signed-off-by: Florian Lehner <dev@der-flo.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201029201442.596690-1-dev@der-flo.net
Zero-fill element values for all other cpus than current, just as
when not using prealloc. This is the only way the bpf program can
ensure known initial values for all cpus ('onallcpus' cannot be
set when coming from the bpf program).
The scenario is: bpf program inserts some elements in a per-cpu
map, then deletes some (or userspace does). When later adding
new elements using bpf_map_update_elem(), the bpf program can
only set the value of the new elements for the current cpu.
When prealloc is enabled, previously deleted elements are re-used.
Without the fix, values for other cpus remain whatever they were
when the re-used entry was previously freed.
A selftest is added to validate correct operation in above
scenario as well as in case of LRU per-cpu map element re-use.
Fixes: 6c90598174 ("bpf: pre-allocate hash map elements")
Signed-off-by: David Verbeiren <david.verbeiren@tessares.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201104112332.15191-1-david.verbeiren@tessares.net
If a hashtab is accessed in both non-NMI and NMI context, the system may
deadlock on bucket->lock. Fix this issue with percpu counter map_locked.
map_locked rejects concurrent access to the same bucket from the same CPU.
To reduce memory overhead, map_locked is not added per bucket. Instead,
8 percpu counters are added to each hashtab. buckets are assigned to these
counters based on the lower bits of its hash.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201029071925.3103400-3-songliubraving@fb.com
