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Make sure verifier rejects the bad cases and ensure the good case keeps
working. The selftests make use of the bpf_kfunc_call_test_ref kfunc
added in the previous patch only for verification.
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-11-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Introduce bpf_ct_set_status and bpf_ct_change_status kfunc helpers in
order to set nf_conn field of allocated entry or update nf_conn status
field of existing inserted entry. Use nf_ct_change_status_common to
share the permitted status field changes between netlink and BPF side
by refactoring ctnetlink_change_status.
It is required to introduce two kfuncs taking nf_conn___init and nf_conn
instead of sharing one because KF_TRUSTED_ARGS flag causes strict type
checking. This would disallow passing nf_conn___init to kfunc taking
nf_conn, and vice versa. We cannot remove the KF_TRUSTED_ARGS flag as we
only want to accept refcounted pointers and not e.g. ct->master.
Hence, bpf_ct_set_* kfuncs are meant to be used on allocated CT, and
bpf_ct_change_* kfuncs are meant to be used on inserted or looked up
CT entry.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-10-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Introduce bpf_ct_set_timeout and bpf_ct_change_timeout kfunc helpers in
order to change nf_conn timeout. This is same as ctnetlink_change_timeout,
hence code is shared between both by extracting it out to
__nf_ct_change_timeout. It is also updated to return an error when it
sees IPS_FIXED_TIMEOUT_BIT bit in ct->status, as that check was missing.
It is required to introduce two kfuncs taking nf_conn___init and nf_conn
instead of sharing one because KF_TRUSTED_ARGS flag causes strict type
checking. This would disallow passing nf_conn___init to kfunc taking
nf_conn, and vice versa. We cannot remove the KF_TRUSTED_ARGS flag as we
only want to accept refcounted pointers and not e.g. ct->master.
Apart from this, bpf_ct_set_timeout is only called for newly allocated
CT so it doesn't need to inspect the status field just yet. Sharing the
helpers even if it was possible would make timeout setting helper
sensitive to order of setting status and timeout after allocation.
Hence, bpf_ct_set_* kfuncs are meant to be used on allocated CT, and
bpf_ct_change_* kfuncs are meant to be used on inserted or looked up
CT entry.
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-9-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Introduce bpf_xdp_ct_alloc, bpf_skb_ct_alloc and bpf_ct_insert_entry
kfuncs in order to insert a new entry from XDP and TC programs.
Introduce bpf_nf_ct_tuple_parse utility routine to consolidate common
code.
We extract out a helper __nf_ct_set_timeout, used by the ctnetlink and
nf_conntrack_bpf code, extract it out to nf_conntrack_core, so that
nf_conntrack_bpf doesn't need a dependency on CONFIG_NF_CT_NETLINK.
Later this helper will be reused as a helper to set timeout of allocated
but not yet inserted CT entry.
The allocation functions return struct nf_conn___init instead of
nf_conn, to distinguish allocated CT from an already inserted or looked
up CT. This is later used to enforce restrictions on what kfuncs
allocated CT can be used with.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Move common checks inside the common function, and maintain the only
difference the two being how to obtain the struct net * from ctx.
No functional change intended.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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As the usage of kfuncs grows, we are starting to form consensus on the
kinds of attributes and annotations that kfuncs can have. To better help
developers make sense of the various options available at their disposal
to present an unstable API to the BPF users, document the various kfunc
flags and annotations, their expected usage, and explain the process of
defining and registering a kfunc set.
Cc: KP Singh <kpsingh@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Teach the verifier to detect a new KF_TRUSTED_ARGS kfunc flag, which
means each pointer argument must be trusted, which we define as a
pointer that is referenced (has non-zero ref_obj_id) and also needs to
have its offset unchanged, similar to how release functions expect their
argument. This allows a kfunc to receive pointer arguments unchanged
from the result of the acquire kfunc.
This is required to ensure that kfunc that operate on some object only
work on acquired pointers and not normal PTR_TO_BTF_ID with same type
which can be obtained by pointer walking. The restrictions applied to
release arguments also apply to trusted arguments. This implies that
strict type matching (not deducing type by recursively following members
at offset) and OBJ_RELEASE offset checks (ensuring they are zero) are
used for trusted pointer arguments.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Instead of populating multiple sets to indicate some attribute and then
researching the same BTF ID in them, prepare a single unified BTF set
which indicates whether a kfunc is allowed to be called, and also its
attributes if any at the same time. Now, only one call is needed to
perform the lookup for both kfunc availability and its attributes.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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A flag is a 4-byte symbol that may follow a BTF ID in a set8. This is
used in the kernel to tag kfuncs in BTF sets with certain flags. Add
support to adjust the sorting code so that it passes size as 8 bytes
for 8-byte BTF sets.
Cc: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220721134245.2450-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Introduce support for defining flags for kfuncs using a new set of
macros, BTF_SET8_START/BTF_SET8_END, which define a set which contains
8 byte elements (each of which consists of a pair of BTF ID and flags),
using a new BTF_ID_FLAGS macro.
This will be used to tag kfuncs registered for a certain program type
as acquire, release, sleepable, ret_null, etc. without having to create
more and more sets which was proving to be an unscalable solution.
Now, when looking up whether a kfunc is allowed for a certain program,
we can also obtain its kfunc flags in the same call and avoid further
lookups.
The resolve_btfids change is split into a separate patch.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The Linux man-pages project now uses SPDX tags, instead of the full
license text.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://www.kernel.org/doc/man-pages/licenses.html
Link: https://spdx.org/licenses/Linux-man-pages-copyleft.html
Link: https://lore.kernel.org/bpf/20220721110821.8240-1-alx.manpages@gmail.com
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dummy_tramp() uses "lr" to refer to the x30 register, but some assembler
does not recognize "lr" and reports a build failure:
/tmp/cc52xO0c.s: Assembler messages:
/tmp/cc52xO0c.s:8: Error: operand 1 should be an integer register -- `mov lr,x9'
/tmp/cc52xO0c.s:7: Error: undefined symbol lr used as an immediate value
make[2]: *** [scripts/Makefile.build:250: arch/arm64/net/bpf_jit_comp.o] Error 1
make[1]: *** [scripts/Makefile.build:525: arch/arm64/net] Error 2
So replace "lr" with "x30" to fix it.
Fixes: b2ad54e1533e ("bpf, arm64: Implement bpf_arch_text_poke() for arm64")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/bpf/20220721121319.2999259-1-xukuohai@huaweicloud.com
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Syzkaller found a problem similar to d1a6edecc1fd ("bpf: Check
attach_func_proto more carefully in check_return_code") where
attach_func_proto might be NULL:
RIP: 0010:check_helper_call+0x3dcb/0x8d50 kernel/bpf/verifier.c:7330
do_check kernel/bpf/verifier.c:12302 [inline]
do_check_common+0x6e1e/0xb980 kernel/bpf/verifier.c:14610
do_check_main kernel/bpf/verifier.c:14673 [inline]
bpf_check+0x661e/0xc520 kernel/bpf/verifier.c:15243
bpf_prog_load+0x11ae/0x1f80 kernel/bpf/syscall.c:2620
With the following reproducer:
bpf$BPF_PROG_RAW_TRACEPOINT_LOAD(0x5, &(0x7f0000000780)={0xf, 0x4, &(0x7f0000000040)=@framed={{}, [@call={0x85, 0x0, 0x0, 0xbb}]}, &(0x7f0000000000)='GPL\x00', 0x0, 0x0, 0x0, 0x0, 0x0, '\x00', 0x0, 0x2b, 0xffffffffffffffff, 0x8, 0x0, 0x0, 0x10, 0x0}, 0x80)
Let's do the same here, only check attach_func_proto for the prog types
where we are certain that attach_func_proto is defined.
Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor")
Reported-by: syzbot+0f8d989b1fba1addc5e0@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220720164729.147544-1-sdf@google.com
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The return from strcmp() is inverted so it wrongly returns true instead
of false and vice versa.
Fixes: a1c9d61b19cb ("libbpf: Improve library identification for uprobe binary path resolution")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Cc: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/YtZ+/dAA195d99ak@kili
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The code here is supposed to take a signed int and store it in a signed
long long. Unfortunately, the way that the type promotion works with
this conditional statement is that it takes a signed int, type promotes
it to a __u32, and then stores that as a signed long long. The result is
never negative.
This is from static analysis, but I made a little test program just to
test it before I sent the patch:
#include <stdio.h>
int main(void)
{
unsigned long long src = -1ULL;
signed long long dst1, dst2;
int is_signed = 1;
dst1 = is_signed ? *(int *)&src : *(unsigned int *)0;
dst2 = is_signed ? (signed long long)*(int *)&src : *(unsigned int *)0;
printf("%lld\n", dst1);
printf("%lld\n", dst2);
return 0;
}
Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/YtZ+LpgPADm7BeEd@kili
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They were updated in kernel/bpf/trampoline.c to fix another build
issue. We should to do the same for include/linux/bpf.h header.
Fixes: 3908fcddc65d ("bpf: fix lsm_cgroup build errors on esoteric configs")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220720155220.4087433-1-sdf@google.com
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The snprintf() function returns the number of bytes it *would* have
copied if there were enough space. So it can return > the
sizeof(gen->attach_target).
Fixes: 67234743736a ("libbpf: Generate loader program out of BPF ELF file.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/YtZ+oAySqIhFl6/J@kili
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The snprintf() function returns the number of bytes which *would*
have been copied if there were space. In other words, it can be
> sizeof(pin_path).
Fixes: c0fa1b6c3efc ("bpf: btf: Add BTF tests")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/YtZ+aD/tZMkgOUw+@kili
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Kumar Kartikeya Dwivedi
Lorenzo Bianconi
Alejandro Colomar
Xu Kuohai
Stanislav Fomichev
Dan Carpenter