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2023-01-05Merge tag 'for-netdev' of ↵Jakub Kicinski6-20/+342
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Daniel Borkmann says: ==================== bpf-next 2023-01-04 We've added 45 non-merge commits during the last 21 day(s) which contain a total of 50 files changed, 1454 insertions(+), 375 deletions(-). The main changes are: 1) Fixes, improvements and refactoring of parts of BPF verifier's state equivalence checks, from Andrii Nakryiko. 2) Fix a few corner cases in libbpf's BTF-to-C converter in particular around padding handling and enums, also from Andrii Nakryiko. 3) Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata, from Christian Ehrig. 4) Improve x86 JIT's codegen for PROBE_MEM runtime error checks, from Dave Marchevsky. 5) Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers, from Jiri Olsa. 6) Add proper documentation for BPF_MAP_TYPE_SOCK{MAP,HASH} maps, from Maryam Tahhan. 7) Improvements in libbpf's btf_parse_elf error handling, from Changbin Du. 8) Bigger batch of improvements to BPF tracing code samples, from Daniel T. Lee. 9) Add LoongArch support to libbpf's bpf_tracing helper header, from Hengqi Chen. 10) Fix a libbpf compiler warning in perf_event_open_probe on arm32, from Khem Raj. 11) Optimize bpf_local_storage_elem by removing 56 bytes of padding, from Martin KaFai Lau. 12) Use pkg-config to locate libelf for resolve_btfids build, from Shen Jiamin. 13) Various libbpf improvements around API documentation and errno handling, from Xin Liu. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits) libbpf: Return -ENODATA for missing btf section libbpf: Add LoongArch support to bpf_tracing.h libbpf: Restore errno after pr_warn. libbpf: Added the description of some API functions libbpf: Fix invalid return address register in s390 samples/bpf: Use BPF_KSYSCALL macro in syscall tracing programs samples/bpf: Fix tracex2 by using BPF_KSYSCALL macro samples/bpf: Change _kern suffix to .bpf with syscall tracing program samples/bpf: Use vmlinux.h instead of implicit headers in syscall tracing program samples/bpf: Use kyscall instead of kprobe in syscall tracing program bpf: rename list_head -> graph_root in field info types libbpf: fix errno is overwritten after being closed. bpf: fix regs_exact() logic in regsafe() to remap IDs correctly bpf: perform byte-by-byte comparison only when necessary in regsafe() bpf: reject non-exact register type matches in regsafe() bpf: generalize MAYBE_NULL vs non-MAYBE_NULL rule bpf: reorganize struct bpf_reg_state fields bpf: teach refsafe() to take into account ID remapping bpf: Remove unused field initialization in bpf's ctl_table selftests/bpf: Add jit probe_mem corner case tests to s390x denylist ... ==================== Link: https://lore.kernel.org/r/20230105000926.31350-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-23selftests/bpf: check null propagation only neither reg is PTR_TO_BTF_IDHao Sun1-0/+42
Verify that nullness information is not porpagated in the branches of register to register JEQ and JNE operations if one of them is PTR_TO_BTF_ID. Implement this in C level so we can use CO-RE. Signed-off-by: Hao Sun <sunhao.th@gmail.com> Suggested-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20221222024414.29539-2-sunhao.th@gmail.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-12-22selftests/bpf: Test bpf_skb_adjust_room on CHECKSUM_PARTIALMartin KaFai Lau2-0/+74
When the bpf_skb_adjust_room() shrinks the skb such that its csum_start is invalid, the skb->ip_summed should be reset from CHECKSUM_PARTIAL to CHECKSUM_NONE. The commit 54c3f1a81421 ("bpf: pull before calling skb_postpull_rcsum()") fixed it. This patch adds a test to ensure the skb->ip_summed changed from CHECKSUM_PARTIAL to CHECKSUM_NONE after bpf_skb_adjust_room(). Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20221221185653.1589961-1-martin.lau@linux.dev
2022-12-22selftests/bpf: Add verifier test exercising jit PROBE_MEM logicDave Marchevsky1-0/+61
This patch adds a test exercising logic that was fixed / improved in the previous patch in the series, as well as general sanity checking for jit's PROBE_MEM logic which should've been unaffected by the previous patch. The added verifier test does the following: * Acquire a referenced kptr to struct prog_test_ref_kfunc using existing net/bpf/test_run.c kfunc * Helper returns ptr to a specific prog_test_ref_kfunc whose first two fields - both ints - have been prepopulated w/ vals 42 and 108, respectively * kptr_xchg the acquired ptr into an arraymap * Do a direct map_value load of the just-added ptr * Goal of all this setup is to get an unreferenced kptr pointing to struct with ints of known value, which is the result of this step * Using unreferenced kptr obtained in previous step, do loads of prog_test_ref_kfunc.a (offset 0) and .b (offset 4) * Then incr the kptr by 8 and load prog_test_ref_kfunc.a again (this time at offset -8) * Add all the loaded ints together and return Before the PROBE_MEM fixes in previous patch, the loads at offset 0 and 4 would succeed, while the load at offset -8 would incorrectly fail runtime check emitted by the JIT and 0 out dst reg as a result. This confirmed by retval of 150 for this test before previous patch - since second .a read is 0'd out - and a retval of 192 with the fixed logic. The test exercises the two optimizations to fixed logic added in last patch as well: * First load, with insn "r8 = *(u32 *)(r9 + 0)" exercises "insn->off is 0, no need to add / sub from src_reg" optimization * Third load, with insn "r9 = *(u32 *)(r9 - 8)" exercises "src_reg == dst_reg, no need to restore src_reg after load" optimization Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20221216214319.3408356-2-davemarchevsky@fb.com
2022-12-20selftests/bpf: Add BPF_F_NO_TUNNEL_KEY testChristian Ehrig1-0/+21
This patch adds a selftest simulating a GRE sender and receiver using tunnel headers without tunnel keys. It validates if packets encapsulated using BPF_F_NO_TUNNEL_KEY are decapsulated by a GRE receiver not configured with tunnel keys. Signed-off-by: Christian Ehrig <cehrig@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20221218051734.31411-2-cehrig@cloudflare.com
2022-12-16libbpf: Fix btf_dump's packed struct determinationAndrii Nakryiko1-0/+19
Fix bug in btf_dump's logic of determining if a given struct type is packed or not. The notion of "natural alignment" is not needed and is even harmful in this case, so drop it altogether. The biggest difference in btf_is_struct_packed() compared to its original implementation is that we don't really use btf__align_of() to determine overall alignment of a struct type (because it could be 1 for both packed and non-packed struct, depending on specifci field definitions), and just use field's actual alignment to calculate whether any field is requiring packing or struct's size overall necessitates packing. Add two simple test cases that demonstrate the difference this change would make. Fixes: ea2ce1ba99aa ("libbpf: Fix BTF-to-C converter's padding logic") Reported-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20221215183605.4149488-1-andrii@kernel.org
2022-12-15selftests/bpf: Add a test for using a cpumap from an freplace-to-XDP programToke Høiland-Jørgensen1-0/+24
This adds a simple test for inserting an XDP program into a cpumap that is "owned" by an XDP program that was loaded as PROG_TYPE_EXT (as libxdp does). Prior to the kernel fix this would fail because the map type ownership would be set to PROG_TYPE_EXT instead of being resolved to PROG_TYPE_XDP. v5: - Fix a few nits from Andrii, add his ACK v4: - Use skeletons for selftest v3: - Update comment to better explain the cause - Add Yonghong's ACK Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/r/20221214230254.790066-2-toke@redhat.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-12-15selftests/bpf: Add few corner cases to test padding handling of btf_dumpAndrii Nakryiko2-1/+164
Add few hand-crafted cases and few randomized cases found using script from [0] that tests btf_dump's padding logic. [0] https://lore.kernel.org/bpf/85f83c333f5355c8ac026f835b18d15060725fcb.camel@ericsson.com/ Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221212211505.558851-7-andrii@kernel.org
2022-12-15libbpf: Fix BTF-to-C converter's padding logicAndrii Nakryiko2-19/+41
Turns out that btf_dump API doesn't handle a bunch of tricky corner cases, as reported by Per, and further discovered using his testing Python script ([0]). This patch revamps btf_dump's padding logic significantly, making it more correct and also avoiding unnecessary explicit padding, where compiler would pad naturally. This overall topic turned out to be very tricky and subtle, there are lots of subtle corner cases. The comments in the code tries to give some clues, but comments themselves are supposed to be paired with good understanding of C alignment and padding rules. Plus some experimentation to figure out subtle things like whether `long :0;` means that struct is now forced to be long-aligned (no, it's not, turns out). Anyways, Per's script, while not completely correct in some known situations, doesn't show any obvious cases where this logic breaks, so this is a nice improvement over the previous state of this logic. Some selftests had to be adjusted to accommodate better use of natural alignment rules, eliminating some unnecessary padding, or changing it to `type: 0;` alignment markers. Note also that for when we are in between bitfields, we emit explicit bit size, while otherwise we use `: 0`, this feels much more natural in practice. Next patch will add few more test cases, found through randomized Per's script. [0] https://lore.kernel.org/bpf/85f83c333f5355c8ac026f835b18d15060725fcb.camel@ericsson.com/ Reported-by: Per Sundström XP <per.xp.sundstrom@ericsson.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221212211505.558851-6-andrii@kernel.org
2022-12-15selftests/bpf: Add non-standardly sized enum tests for btf_dumpAndrii Nakryiko1-0/+36
Add few custom enum definitions testing mode(byte) and mode(word) attributes. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221212211505.558851-4-andrii@kernel.org
2022-12-14selftests/bpf: Fix a selftest compilation error with CONFIG_SMP=nYonghong Song2-5/+5
Kernel test robot reported bpf selftest build failure when CONFIG_SMP is not set. The error message looks below: >> progs/rcu_read_lock.c:256:34: error: no member named 'last_wakee' in 'struct task_struct' last_wakee = task->real_parent->last_wakee; ~~~~~~~~~~~~~~~~~ ^ 1 error generated. When CONFIG_SMP is not set, the field 'last_wakee' is not available in struct 'task_struct'. Hence the above compilation failure. To fix the issue, let us choose another field 'group_leader' which is available regardless of CONFIG_SMP set or not. Fixes: fe147956fca4 ("bpf/selftests: Add selftests for new task kfuncs") Fixes: 48671232fcb8 ("selftests/bpf: Add tests for bpf_rcu_read_lock()") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20221213012224.379581-1-yhs@fb.com
2022-12-09selftests/bpf: Add test for dynptr reinit in user_ringbuf callbackKumar Kartikeya Dwivedi1-8/+43
The original support for bpf_user_ringbuf_drain callbacks simply short-circuited checks for the dynptr state, allowing users to pass PTR_TO_DYNPTR (now CONST_PTR_TO_DYNPTR) to helpers that initialize a dynptr. This bug would have also surfaced with other dynptr helpers in the future that changed dynptr view or modified it in some way. Include test cases for all cases, i.e. both bpf_dynptr_from_mem and bpf_ringbuf_reserve_dynptr, and ensure verifier rejects both of them. Without the fix, both of these programs load and pass verification. While at it, remove sys_nanosleep target from failure cases' SEC definition, as there is no such tracepoint. Acked-by: David Vernet <void@manifault.com> Acked-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221207204141.308952-8-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-09bpf: Refactor ARG_PTR_TO_DYNPTR checks into process_dynptr_funcKumar Kartikeya Dwivedi1-12/+0
ARG_PTR_TO_DYNPTR is akin to ARG_PTR_TO_TIMER, ARG_PTR_TO_KPTR, where the underlying register type is subjected to more special checks to determine the type of object represented by the pointer and its state consistency. Move dynptr checks to their own 'process_dynptr_func' function so that is consistent and in-line with existing code. This also makes it easier to reuse this code for kfunc handling. Then, reuse this consolidated function in kfunc dynptr handling too. Note that for kfuncs, the arg_type constraint of DYNPTR_TYPE_LOCAL has been lifted. Acked-by: David Vernet <void@manifault.com> Acked-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221207204141.308952-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-08selftests/bpf: convert dynptr_fail and map_kptr_fail subtests to generic testerAndrii Nakryiko3-0/+59
Convert big chunks of dynptr and map_kptr subtests to use generic verification_tester. They are switched from using manually maintained tables of test cases, specifying program name and expected error verifier message, to btf_decl_tag-based annotations directly on corresponding BPF programs: __failure to specify that BPF program is expected to fail verification, and __msg() to specify expected log message. Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221207201648.2990661-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-08selftests/bpf: add generic BPF program tester-loaderAndrii Nakryiko1-0/+5
It's become a common pattern to have a collection of small BPF programs in one BPF object file, each representing one test case. On user-space side of such tests we maintain a table of program names and expected failure or success, along with optional expected verifier log message. This works, but each set of tests reimplement this mundane code over and over again, which is a waste of time for anyone trying to add a new set of tests. Furthermore, it's quite error prone as it's way too easy to miss some entries in these manually maintained test tables (as evidences by dynptr_fail tests, in which ringbuf_release_uninit_dynptr subtest was accidentally missed; this is fixed in next patch). So this patch implements generic test_loader, which accepts skeleton name and handles the rest of details: opens and loads BPF object file, making sure each program is tested in isolation. Optionally each test case can specify expected BPF verifier log message. In case of failure, tester makes sure to report verifier log, but it also reports verifier log in verbose mode unconditionally. Now, the interesting deviation from existing custom implementations is the use of btf_decl_tag attribute to specify expected-to-fail vs expected-to-succeed markers and, optionally, expected log message directly next to BPF program source code, eliminating the need to manually create and update table of tests. We define few macros wrapping btf_decl_tag with a convention that all values of btf_decl_tag start with "comment:" prefix, and then utilizing a very simple "just_some_text_tag" or "some_key_name=<value>" pattern to define things like expected success/failure, expected verifier message, extra verifier log level (if necessary). This approach is demonstrated by next patch in which two existing sets of failure tests are converted. Tester supports both expected-to-fail and expected-to-succeed programs, though this patch set didn't convert any existing expected-to-succeed programs yet, as existing tests couple BPF program loading with their further execution through attach or test_prog_run. One way to allow testing scenarios like this would be ability to specify custom callback, executed for each successfully loaded BPF program. This is left for follow up patches, after some more analysis of existing test cases. This test_loader is, hopefully, a start of a test_verifier-like runner, but integrated into test_progs infrastructure. It will allow much better "user experience" of defining low-level verification tests that can take advantage of all the libbpf-provided nicety features on BPF side: global variables, declarative maps, etc. All while having a choice of defining it in C or as BPF assembly (through __attribute__((naked)) functions and using embedded asm), depending on what makes most sense in each particular case. This will be explored in follow up patches as well. Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20221207201648.2990661-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-07bpf: Don't use rcu_users to refcount in task kfuncsDavid Vernet2-2/+12
A series of prior patches added some kfuncs that allow struct task_struct * objects to be used as kptrs. These kfuncs leveraged the 'refcount_t rcu_users' field of the task for performing refcounting. This field was used instead of 'refcount_t usage', as we wanted to leverage the safety provided by RCU for ensuring a task's lifetime. A struct task_struct is refcounted by two different refcount_t fields: 1. p->usage: The "true" refcount field which task lifetime. The task is freed as soon as this refcount drops to 0. 2. p->rcu_users: An "RCU users" refcount field which is statically initialized to 2, and is co-located in a union with a struct rcu_head field (p->rcu). p->rcu_users essentially encapsulates a single p->usage refcount, and when p->rcu_users goes to 0, an RCU callback is scheduled on the struct rcu_head which decrements the p->usage refcount. Our logic was that by using p->rcu_users, we would be able to use RCU to safely issue refcount_inc_not_zero() a task's rcu_users field to determine if a task could still be acquired, or was exiting. Unfortunately, this does not work due to p->rcu_users and p->rcu sharing a union. When p->rcu_users goes to 0, an RCU callback is scheduled to drop a single p->usage refcount, and because the fields share a union, the refcount immediately becomes nonzero again after the callback is scheduled. If we were to split the fields out of the union, this wouldn't be a problem. Doing so should also be rather non-controversial, as there are a number of places in struct task_struct that have padding which we could use to avoid growing the structure by splitting up the fields. For now, so as to fix the kfuncs to be correct, this patch instead updates bpf_task_acquire() and bpf_task_release() to use the p->usage field for refcounting via the get_task_struct() and put_task_struct() functions. Because we can no longer rely on RCU, the change also guts the bpf_task_acquire_not_zero() and bpf_task_kptr_get() functions pending a resolution on the above problem. In addition, the task fixes the kfunc and rcu_read_lock selftests to expect this new behavior. Fixes: 90660309b0c7 ("bpf: Add kfuncs for storing struct task_struct * as a kptr") Fixes: fca1aa75518c ("bpf: Handle MEM_RCU type properly") Reported-by: Matus Jokay <matus.jokay@stuba.sk> Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20221206210538.597606-1-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-06selftests/bpf: Allow building bpf tests with CONFIG_XFRM_INTERFACE=[m|n]Martin KaFai Lau1-4/+9
It is useful to use vmlinux.h in the xfrm_info test like other kfunc tests do. In particular, it is common for kfunc bpf prog that requires to use other core kernel structures in vmlinux.h Although vmlinux.h is preferred, it needs a ___local flavor of struct bpf_xfrm_info in order to build the bpf selftests when CONFIG_XFRM_INTERFACE=[m|n]. Cc: Eyal Birger <eyal.birger@gmail.com> Fixes: 90a3a05eb33f ("selftests/bpf: add xfrm_info tests") Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20221206193554.1059757-1-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-06selftests/bpf: add xfrm_info testsEyal Birger2-0/+38
Test the xfrm_info kfunc helpers. The test setup creates three name spaces - NS0, NS1, NS2. XFRM tunnels are setup between NS0 and the two other NSs. The kfunc helpers are used to steer traffic from NS0 to the other NSs based on a userspace populated bpf global variable and validate that the return traffic had arrived from the desired NS. Signed-off-by: Eyal Birger <eyal.birger@gmail.com> Link: https://lore.kernel.org/r/20221203084659.1837829-5-eyal.birger@gmail.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-12-05selftests/bpf: Fix conflicts with built-in functions in bpf_iter_ksymJames Hilliard1-3/+3
Both tolower and toupper are built in c functions, we should not redefine them as this can result in a build error. Fixes the following errors: progs/bpf_iter_ksym.c:10:20: error: conflicting types for built-in function 'tolower'; expected 'int(int)' [-Werror=builtin-declaration-mismatch] 10 | static inline char tolower(char c) | ^~~~~~~ progs/bpf_iter_ksym.c:5:1: note: 'tolower' is declared in header '<ctype.h>' 4 | #include <bpf/bpf_helpers.h> +++ |+#include <ctype.h> 5 | progs/bpf_iter_ksym.c:17:20: error: conflicting types for built-in function 'toupper'; expected 'int(int)' [-Werror=builtin-declaration-mismatch] 17 | static inline char toupper(char c) | ^~~~~~~ progs/bpf_iter_ksym.c:17:20: note: 'toupper' is declared in header '<ctype.h>' See background on this sort of issue: https://stackoverflow.com/a/20582607 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=12213 (C99, 7.1.3p1) "All identifiers with external linkage in any of the following subclauses (including the future library directions) are always reserved for use as identifiers with external linkage." This is documented behavior in GCC: https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#index-std-2 Signed-off-by: James Hilliard <james.hilliard1@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20221203010847.2191265-1-james.hilliard1@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-05bpf: Add sleepable prog tests for cgrp local storageYonghong Song1-0/+80
Add three tests for cgrp local storage support for sleepable progs. Two tests can load and run properly, one for cgroup_iter, another for passing current->cgroups->dfl_cgrp to bpf_cgrp_storage_get() helper. One test has bpf_rcu_read_lock() and failed to load. Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221201050449.2785613-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-04bpf: Do not mark certain LSM hook arguments as trustedYonghong Song1-0/+11
Martin mentioned that the verifier cannot assume arguments from LSM hook sk_alloc_security being trusted since after the hook is called, the sk ref_count is set to 1. This will overwrite the ref_count changed by the bpf program and may cause ref_count underflow later on. I then further checked some other hooks. For example, for bpf_lsm_file_alloc() hook in fs/file_table.c, f->f_cred = get_cred(cred); error = security_file_alloc(f); if (unlikely(error)) { file_free_rcu(&f->f_rcuhead); return ERR_PTR(error); } atomic_long_set(&f->f_count, 1); The input parameter 'f' to security_file_alloc() cannot be trusted as well. Specifically, I investiaged bpf_map/bpf_prog/file/sk/task alloc/free lsm hooks. Except bpf_map_alloc and task_alloc, arguments for all other hooks should not be considered as trusted. This may not be a complete list, but it covers common usage for sk and task. Fixes: 3f00c5239344 ("bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs") Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221203204954.2043348-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-04selftests/bpf: Fix rcu_read_lock test with new MEM_RCU semanticsYonghong Song1-10/+45
Add MEM_RCU pointer null checking for related tests. Also modified task_acquire test so it takes a rcu ptr 'ptr' where 'ptr = rcu_ptr->rcu_field'. Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221203184607.478314-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-02selftests/bpf: Validate multiple ref release_on_unlock logicDave Marchevsky1-1/+16
Modify list_push_pop_multiple to alloc and insert nodes 2-at-a-time. Without the previous patch's fix, this block of code: bpf_spin_lock(lock); bpf_list_push_front(head, &f[i]->node); bpf_list_push_front(head, &f[i + 1]->node); bpf_spin_unlock(lock); would fail check_reference_leak check as release_on_unlock logic would miss a ref that should've been released. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> cc: Kumar Kartikeya Dwivedi <memxor@gmail.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221201183406.1203621-2-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-01bpf: Tighten ptr_to_btf_id checks.Alexei Starovoitov1-0/+1
The networking programs typically don't require CAP_PERFMON, but through kfuncs like bpf_cast_to_kern_ctx() they can access memory through PTR_TO_BTF_ID. In such case enforce CAP_PERFMON. Also make sure that only GPL programs can access kernel data structures. All kfuncs require GPL already. Also remove allow_ptr_to_map_access. It's the same as allow_ptr_leaks and different name for the same check only causes confusion. Fixes: fd264ca02094 ("bpf: Add a kfunc to type cast from bpf uapi ctx to kernel ctx") Fixes: 50c6b8a9aea2 ("selftests/bpf: Add a test for btf_type_tag "percpu"") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20221125220617.26846-1-alexei.starovoitov@gmail.com
2022-11-29Daniel Borkmann says:Jakub Kicinski15-2/+2700
==================== bpf-next 2022-11-25 We've added 101 non-merge commits during the last 11 day(s) which contain a total of 109 files changed, 8827 insertions(+), 1129 deletions(-). The main changes are: 1) Support for user defined BPF objects: the use case is to allocate own objects, build own object hierarchies and use the building blocks to build own data structures flexibly, for example, linked lists in BPF, from Kumar Kartikeya Dwivedi. 2) Add bpf_rcu_read_{,un}lock() support for sleepable programs, from Yonghong Song. 3) Add support storing struct task_struct objects as kptrs in maps, from David Vernet. 4) Batch of BPF map documentation improvements, from Maryam Tahhan and Donald Hunter. 5) Improve BPF verifier to propagate nullness information for branches of register to register comparisons, from Eduard Zingerman. 6) Fix cgroup BPF iter infra to hold reference on the start cgroup, from Hou Tao. 7) Fix BPF verifier to not mark fentry/fexit program arguments as trusted given it is not the case for them, from Alexei Starovoitov. 8) Improve BPF verifier's realloc handling to better play along with dynamic runtime analysis tools like KASAN and friends, from Kees Cook. 9) Remove legacy libbpf mode support from bpftool, from Sahid Orentino Ferdjaoui. 10) Rework zero-len skb redirection checks to avoid potentially breaking existing BPF test infra users, from Stanislav Fomichev. 11) Two small refactorings which are independent and have been split out of the XDP queueing RFC series, from Toke Høiland-Jørgensen. 12) Fix a memory leak in LSM cgroup BPF selftest, from Wang Yufen. 13) Documentation on how to run BPF CI without patch submission, from Daniel Müller. Signed-off-by: Jakub Kicinski <kuba@kernel.org> ==================== Link: https://lore.kernel.org/r/20221125012450.441-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-24selftests/bpf: Add tests for bpf_rcu_read_lock()Yonghong Song1-0/+290
Add a few positive/negative tests to test bpf_rcu_read_lock() and its corresponding verifier support. The new test will fail on s390x and aarch64, so an entry is added to each of their respective deny lists. Acked-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221124053222.2374650-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-24selftests/bpf: Add selftests for bpf_task_from_pid()David Vernet3-0/+87
Add some selftest testcases that validate the expected behavior of the bpf_task_from_pid() kfunc that was added in the prior patch. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20221122145300.251210-3-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-23selftests/bpf: Add selftests for bpf_cgroup_ancestor() kfuncDavid Vernet2-0/+46
bpf_cgroup_ancestor() allows BPF programs to access the ancestor of a struct cgroup *. This patch adds selftests that validate its expected behavior. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20221122055458.173143-5-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-23selftests/bpf: Add cgroup kfunc / kptr selftestsDavid Vernet3-0/+456
This patch adds a selftest suite to validate the cgroup kfuncs that were added in the prior patch. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20221122055458.173143-3-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-23selftests/bpf: Workaround for llvm nop-4 bugAlexei Starovoitov1-1/+1
Currently LLVM fails to recognize .data.* as data section and defaults to .text section. Later BPF backend tries to emit 4-byte NOP instruction which doesn't exist in BPF ISA and aborts. The fix for LLVM is pending: https://reviews.llvm.org/D138477 While waiting for the fix lets workaround the linked_list test case by using .bss.* prefix which is properly recognized by LLVM as BSS section. Fix libbpf to support .bss. prefix and adjust tests. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-23Revert "selftests/bpf: Temporarily disable linked list tests"Alexei Starovoitov3-20/+9
This reverts commit 0a2f85a1be4328d29aefa54684d10c23a3298fef. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-21selftests/bpf: Make sure zero-len skbs aren't redirectableStanislav Fomichev1-0/+37
LWT_XMIT to test L3 case, TC to test L2 case. v2: - s/veth_ifindex/ipip_ifindex/ in two places (Martin) - add comment about which condition triggers the rejection (Martin) Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20221121180340.1983627-2-sdf@google.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-11-21bpf: Add type cast unit testsYonghong Song1-0/+83
Three tests are added. One is from John Fastabend ({1]) which tests tracing style access for xdp program from the kernel ctx. Another is a tc test to test both kernel ctx tracing style access and explicit non-ctx type cast. The third one is for negative tests including two tests, a tp_bpf test where the bpf_rdonly_cast() returns a untrusted ptr which cannot be used as helper argument, and a tracepoint test where the kernel ctx is a u64. Also added the test to DENYLIST.s390x since s390 does not currently support calling kernel functions in JIT mode. [1] https://lore.kernel.org/bpf/20221109215242.1279993-1-john.fastabend@gmail.com/ Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221120195442.3114844-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-20bpf/selftests: Add selftests for new task kfuncsDavid Vernet3-0/+480
A previous change added a series of kfuncs for storing struct task_struct objects as referenced kptrs. This patch adds a new task_kfunc test suite for validating their expected behavior. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20221120051004.3605026-5-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-18selftests/bpf: Temporarily disable linked list testsKumar Kartikeya Dwivedi3-9/+20
The latest clang nightly as of writing crashes with the given test case for BPF linked lists wherever global glock, ghead, glock2 are used, hence comment out the parts that cause the crash, and prepare this commit so that it can be reverted when the fix has been made. More context in [0]. [0]: https://lore.kernel.org/bpf/d56223f9-483e-fbc1-4564-44c0858a1e3e@meta.com Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221118015614.2013203-25-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-18selftests/bpf: Add BPF linked list API testsKumar Kartikeya Dwivedi3-0/+1007
Include various tests covering the success and failure cases. Also, run the success cases at runtime to verify correctness of linked list manipulation routines, in addition to ensuring successful verification. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221118015614.2013203-23-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-18selftests/bpf: Add failure test cases for spin lock pairingKumar Kartikeya Dwivedi1-0/+204
First, ensure that whenever a bpf_spin_lock is present in an allocation, the reg->id is preserved. This won't be true for global variables however, since they have a single map value per map, hence the verifier harcodes it to 0 (so that multiple pseudo ldimm64 insns can yield the same lock object per map at a given offset). Next, add test cases for all possible combinations (kptr, global, map value, inner map value). Since we lifted restriction on locking in inner maps, also add test cases for them. Currently, each lookup into an inner map gets a fresh reg->id, so even if the reg->map_ptr is same, they will be treated as separate allocations and the incorrect unlock pairing will be rejected. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221118015614.2013203-22-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-18selftests/bpf: Update spinlock selftestKumar Kartikeya Dwivedi1-2/+2
Make updates in preparation for adding more test cases to this selftest: - Convert from CHECK_ to ASSERT macros. - Use BPF skeleton - Fix typo sping -> spin - Rename spinlock.c -> spin_lock.c Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221118015614.2013203-21-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-0/+5
include/linux/bpf.h 1f6e04a1c7b8 ("bpf: Fix offset calculation error in __copy_map_value and zero_map_value") aa3496accc41 ("bpf: Refactor kptr_off_tab into btf_record") f71b2f64177a ("bpf: Refactor map->off_arr handling") https://lore.kernel.org/all/20221114095000.67a73239@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-17selftests/bpf: fix memory leak of lsm_cgroupWang Yufen1-0/+8
kmemleak reports this issue: unreferenced object 0xffff88810b7835c0 (size 32): comm "test_progs", pid 270, jiffies 4294969007 (age 1621.315s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 03 00 00 00 03 00 00 00 0f 00 00 00 00 00 00 00 ................ backtrace: [<00000000376cdeab>] kmalloc_trace+0x27/0x110 [<000000003bcdb3b6>] selinux_sk_alloc_security+0x66/0x110 [<000000003959008f>] security_sk_alloc+0x47/0x80 [<00000000e7bc6668>] sk_prot_alloc+0xbd/0x1a0 [<0000000002d6343a>] sk_alloc+0x3b/0x940 [<000000009812a46d>] unix_create1+0x8f/0x3d0 [<000000005ed0976b>] unix_create+0xa1/0x150 [<0000000086a1d27f>] __sock_create+0x233/0x4a0 [<00000000cffe3a73>] __sys_socket_create.part.0+0xaa/0x110 [<0000000007c63f20>] __sys_socket+0x49/0xf0 [<00000000b08753c8>] __x64_sys_socket+0x42/0x50 [<00000000b56e26b3>] do_syscall_64+0x3b/0x90 [<000000009b4871b8>] entry_SYSCALL_64_after_hwframe+0x63/0xcd The issue occurs in the following scenarios: unix_create1() sk_alloc() sk_prot_alloc() security_sk_alloc() call_int_hook() hlist_for_each_entry() entry1->hook.sk_alloc_security <-- selinux_sk_alloc_security() succeeded, <-- sk->security alloced here. entry2->hook.sk_alloc_security <-- bpf_lsm_sk_alloc_security() failed goto out_free; ... <-- the sk->security not freed, memleak The core problem is that the LSM is not yet fully stacked (work is actively going on in this space) which means that some LSM hooks do not support multiple LSMs at the same time. To fix, skip the "EPERM" test when it runs in the environments that already have non-bpf lsms installed Fixes: dca85aac8895 ("selftests/bpf: lsm_cgroup functional test") Signed-off-by: Wang Yufen <wangyufen@huawei.com> Cc: Stanislav Fomichev <sdf@google.com> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/1668482980-16163-1-git-send-email-wangyufen@huawei.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-11-12selftests/bpf: Test skops->skb_hwtstampMartin KaFai Lau1-0/+4
This patch tests reading the skops->skb_hwtstamp field. A local test was also done such that the shinfo hwtstamp was temporary set to a non zero value in the kernel bpf_skops_parse_hdr() and the same value can be read by the skops test. An adjustment is needed to the btf_dump selftest because the changes in the 'struct bpf_sock_ops'. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20221107230420.4192307-4-martin.lau@linux.dev
2022-11-11selftests: bpf: Add a test when bpf_probe_read_kernel_str() returns EFAULTAlban Crequy1-0/+5
This commit tests previous fix of bpf_probe_read_kernel_str(). The BPF helper bpf_probe_read_kernel_str should return -EFAULT when given a bad source pointer and the target buffer should only be modified to make the string NULL terminated. bpf_probe_read_kernel_str() was previously inserting a NULL before the beginning of the dst buffer. This test should ensure that the implementation stays correct for now on. Without the fix, this test will fail as follows: $ cd tools/testing/selftests/bpf $ make $ sudo ./test_progs --name=varlen ... test_varlen:FAIL:check got 0 != exp 66 Signed-off-by: Alban Crequy <albancrequy@linux.microsoft.com> Signed-off-by: Francis Laniel <flaniel@linux.microsoft.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20221110085614.111213-3-albancrequy@linux.microsoft.com Changes v1 to v2: - add ack tag - fix my email - rebase on bpf tree and tag for bpf tree
2022-11-02Merge tag 'for-netdev' of ↵Jakub Kicinski12-4/+538
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Daniel Borkmann says: ==================== bpf-next 2022-11-02 We've added 70 non-merge commits during the last 14 day(s) which contain a total of 96 files changed, 3203 insertions(+), 640 deletions(-). The main changes are: 1) Make cgroup local storage available to non-cgroup attached BPF programs such as tc BPF ones, from Yonghong Song. 2) Avoid unnecessary deadlock detection and failures wrt BPF task storage helpers, from Martin KaFai Lau. 3) Add LLVM disassembler as default library for dumping JITed code in bpftool, from Quentin Monnet. 4) Various kprobe_multi_link fixes related to kernel modules, from Jiri Olsa. 5) Optimize x86-64 JIT with emitting BMI2-based shift instructions, from Jie Meng. 6) Improve BPF verifier's memory type compatibility for map key/value arguments, from Dave Marchevsky. 7) Only create mmap-able data section maps in libbpf when data is exposed via skeletons, from Andrii Nakryiko. 8) Add an autoattach option for bpftool to load all object assets, from Wang Yufen. 9) Various memory handling fixes for libbpf and BPF selftests, from Xu Kuohai. 10) Initial support for BPF selftest's vmtest.sh on arm64, from Manu Bretelle. 11) Improve libbpf's BTF handling to dedup identical structs, from Alan Maguire. 12) Add BPF CI and denylist documentation for BPF selftests, from Daniel Müller. 13) Check BPF cpumap max_entries before doing allocation work, from Florian Lehner. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (70 commits) samples/bpf: Fix typo in README bpf: Remove the obsolte u64_stats_fetch_*_irq() users. bpf: check max_entries before allocating memory bpf: Fix a typo in comment for DFS algorithm bpftool: Fix spelling mistake "disasembler" -> "disassembler" selftests/bpf: Fix bpftool synctypes checking failure selftests/bpf: Panic on hard/soft lockup docs/bpf: Add documentation for new cgroup local storage selftests/bpf: Add test cgrp_local_storage to DENYLIST.s390x selftests/bpf: Add selftests for new cgroup local storage selftests/bpf: Fix test test_libbpf_str/bpf_map_type_str bpftool: Support new cgroup local storage libbpf: Support new cgroup local storage bpf: Implement cgroup storage available to non-cgroup-attached bpf progs bpf: Refactor some inode/task/sk storage functions for reuse bpf: Make struct cgroup btf id global selftests/bpf: Tracing prog can still do lookup under busy lock selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to deadlock detection bpf: Add new bpf_task_storage_delete proto with no deadlock detection bpf: bpf_task_storage_delete_recur does lookup first before the deadlock check ... ==================== Link: https://lore.kernel.org/r/20221102062120.5724-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-10-26selftests/bpf: Add selftests for new cgroup local storageYonghong Song4-0/+285
Add four tests for new cgroup local storage, (1) testing bpf program helpers and user space map APIs, (2) testing recursive fentry triggering won't deadlock, (3) testing progs attached to cgroups, and (4) a negative test if the bpf_cgrp_storage_get() helper key is not a cgroup btf id. Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221026042911.675546-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-10-26selftests/bpf: Tracing prog can still do lookup under busy lockMartin KaFai Lau1-3/+40
This patch modifies the task_ls_recursion test to check that the first bpf_task_storage_get(&map_a, ...) in BPF_PROG(on_update) can still do the lockless lookup even it cannot acquire the percpu busy lock. If the lookup succeeds, it will increment the value by 1 and the value in the task storage map_a will become 200+1=201. After that, BPF_PROG(on_update) tries to delete from map_a and should get -EBUSY because it cannot acquire the percpu busy lock after finding the data. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20221025184524.3526117-10-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-10-26selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to ↵Martin KaFai Lau1-0/+47
deadlock detection This patch adds a test to check for deadlock failure in bpf_task_storage_{get,delete} when called by a sleepable bpf_lsm prog. It also checks if the prog_info.recursion_misses is non zero. The test starts with 32 threads and they are affinitized to one cpu. In my qemu setup, with CONFIG_PREEMPT=y, I can reproduce it within one second if it is run without the previous patches of this set. Here is the test error message before adding the no deadlock detection version of the bpf_task_storage_{get,delete}: test_nodeadlock:FAIL:bpf_task_storage_get busy unexpected bpf_task_storage_get busy: actual 2 != expected 0 test_nodeadlock:FAIL:bpf_task_storage_delete busy unexpected bpf_task_storage_delete busy: actual 2 != expected 0 Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20221025184524.3526117-9-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-10-25selftests/bpf: Add kprobe_multi kmod attach api testsJiri Olsa1-0/+50
Adding kprobe_multi kmod attach api tests that attach bpf_testmod functions via bpf_program__attach_kprobe_multi_opts. Running it as serial test, because we don't want other tests to reload bpf_testmod while it's running. Acked-by: Song Liu <song@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20221025134148.3300700-9-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-10-25selftests/bpf: Add kprobe_multi check to module attach testJiri Olsa1-0/+6
Adding test that makes sure the kernel module won't be removed if there's kprobe multi link defined on top of it. Acked-by: Song Liu <song@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20221025134148.3300700-8-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-10-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-2/+2
include/linux/net.h a5ef058dc4d9 ("net: introduce and use custom sockopt socket flag") e993ffe3da4b ("net: flag sockets supporting msghdr originated zerocopy") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-10-22selftests/bpf: Add write to hashmap to array_map iter testDave Marchevsky1-1/+20
Modify iter prog in existing bpf_iter_bpf_array_map.c, which currently dumps arraymap key/val, to also do a write of (val, key) into a newly-added hashmap. Confirm that the write succeeds as expected by modifying the userspace runner program. Before a change added in an earlier commit - considering PTR_TO_BUF reg a valid input to helpers which expect MAP_{KEY,VAL} - the verifier would've rejected this prog change due to type mismatch. Since using current iter's key/val to access a separate map is a reasonable usecase, let's add support for it. Note that the test prog cannot directly write (val, key) into hashmap via bpf_map_update_elem when both come from iter context because key is marked MEM_RDONLY. This is due to bpf_map_update_elem - and other basic map helpers - taking ARG_PTR_TO_MAP_{KEY,VALUE} w/o MEM_RDONLY type flag. bpf_map_{lookup,update,delete}_elem don't modify their input key/val so it should be possible to tag their args READONLY, but due to the ubiquitous use of these helpers and verifier checks for type == MAP_VALUE, such a change is nontrivial and seems better to address in a followup series. Also fixup some 'goto's in test runner's map checking loop. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20221020160721.4030492-4-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>