kernel/linux.git/include/linux/bpf.h, branch v6.6.132

bpf: export bpf_link_inc_not_zero.

2026-03-25T10:05:40+00:00

[ Upstream commit 67c3e8353f45c27800eecc46e00e8272f063f7d1 ] bpf_link_inc_not_zero() will be used by kernel modules. We will use it in bpf_testmod.c later. Signed-off-by: Kui-Feng Lee Link: https://lore.kernel.org/r/20240530065946.979330-5-thinker.li@gmail.com Signed-off-by: Martin KaFai Lau Stable-dep-of: 56145d237385 ("bpf: Fix a UAF issue in bpf_trampoline_link_cgroup_shim") Signed-off-by: Sasha Levin

bpf: Enforce expected_attach_type for tailcall compatibility

2025-10-15T09:57:54+00:00

[ Upstream commit 4540aed51b12bc13364149bf95f6ecef013197c0 ] Yinhao et al. recently reported: Our fuzzer tool discovered an uninitialized pointer issue in the bpf_prog_test_run_xdp() function within the Linux kernel's BPF subsystem. This leads to a NULL pointer dereference when a BPF program attempts to deference the txq member of struct xdp_buff object. The test initializes two programs of BPF_PROG_TYPE_XDP: progA acts as the entry point for bpf_prog_test_run_xdp() and its expected_attach_type can neither be of be BPF_XDP_DEVMAP nor BPF_XDP_CPUMAP. progA calls into a slot of a tailcall map it owns. progB's expected_attach_type must be BPF_XDP_DEVMAP to pass xdp_is_valid_access() validation. The program returns struct xdp_md's egress_ifindex, and the latter is only allowed to be accessed under mentioned expected_attach_type. progB is then inserted into the tailcall which progA calls. The underlying issue goes beyond XDP though. Another example are programs of type BPF_PROG_TYPE_CGROUP_SOCK_ADDR. sock_addr_is_valid_access() as well as sock_addr_func_proto() have different logic depending on the programs' expected_attach_type. Similarly, a program attached to BPF_CGROUP_INET4_GETPEERNAME should not be allowed doing a tailcall into a program which calls bpf_bind() out of BPF which is only enabled for BPF_CGROUP_INET4_CONNECT. In short, specifying expected_attach_type allows to open up additional functionality or restrictions beyond what the basic bpf_prog_type enables. The use of tailcalls must not violate these constraints. Fix it by enforcing expected_attach_type in __bpf_prog_map_compatible(). Note that we only enforce this for tailcall maps, but not for BPF devmaps or cpumaps: There, the programs are invoked through dev_map_bpf_prog_run*() and cpu_map_bpf_prog_run*() which set up a new environment / context and therefore these situations are not prone to this issue. Fixes: 5e43f899b03a ("bpf: Check attach type at prog load time") Reported-by: Yinhao Hu Reported-by: Kaiyan Mei Reviewed-by: Dongliang Mu Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20250926171201.188490-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

bpf: Fix oob access in cgroup local storage

2025-09-09T16:56:19+00:00

[ Upstream commit abad3d0bad72a52137e0c350c59542d75ae4f513 ] Lonial reported that an out-of-bounds access in cgroup local storage can be crafted via tail calls. Given two programs each utilizing a cgroup local storage with a different value size, and one program doing a tail call into the other. The verifier will validate each of the indivial programs just fine. However, in the runtime context the bpf_cg_run_ctx holds an bpf_prog_array_item which contains the BPF program as well as any cgroup local storage flavor the program uses. Helpers such as bpf_get_local_storage() pick this up from the runtime context: ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); storage = ctx->prog_item->cgroup_storage[stype]; if (stype == BPF_CGROUP_STORAGE_SHARED) ptr = &READ_ONCE(storage->buf)->data[0]; else ptr = this_cpu_ptr(storage->percpu_buf); For the second program which was called from the originally attached one, this means bpf_get_local_storage() will pick up the former program's map, not its own. With mismatching sizes, this can result in an unintended out-of-bounds access. To fix this issue, we need to extend bpf_map_owner with an array of storage_cookie[] to match on i) the exact maps from the original program if the second program was using bpf_get_local_storage(), or ii) allow the tail call combination if the second program was not using any of the cgroup local storage maps. Fixes: 7d9c3427894f ("bpf: Make cgroup storages shared between programs on the same cgroup") Reported-by: Lonial Con Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20250730234733.530041-4-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

bpf: Move bpf map owner out of common struct

2025-09-09T16:56:18+00:00

[ Upstream commit fd1c98f0ef5cbcec842209776505d9e70d8fcd53 ] Given this is only relevant for BPF tail call maps, it is adding up space and penalizing other map types. We also need to extend this with further objects to track / compare to. Therefore, lets move this out into a separate structure and dynamically allocate it only for BPF tail call maps. Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20250730234733.530041-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

bpf: Move cgroup iterator helpers to bpf.h

2025-09-09T16:56:18+00:00

[ Upstream commit 9621e60f59eae87eb9ffe88d90f24f391a1ef0f0 ] Move them into bpf.h given we also need them in core code. Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20250730234733.530041-3-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Stable-dep-of: abad3d0bad72 ("bpf: Fix oob access in cgroup local storage") Signed-off-by: Sasha Levin

bpf: Add cookie object to bpf maps

2025-09-09T16:56:18+00:00

[ Upstream commit 12df58ad294253ac1d8df0c9bb9cf726397a671d ] Add a cookie to BPF maps to uniquely identify BPF maps for the timespan when the node is up. This is different to comparing a pointer or BPF map id which could get rolled over and reused. Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20250730234733.530041-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

bpf: check changes_pkt_data property for extension programs

2025-05-09T07:43:54+00:00

commit 81f6d0530ba031b5f038a091619bf2ff29568852 upstream. When processing calls to global sub-programs, verifier decides whether to invalidate all packet pointers in current state depending on the changes_pkt_data property of the global sub-program. Because of this, an extension program replacing a global sub-program must be compatible with changes_pkt_data property of the sub-program being replaced. This commit: - adds changes_pkt_data flag to struct bpf_prog_aux: - this flag is set in check_cfg() for main sub-program; - in jit_subprogs() for other sub-programs; - modifies bpf_check_attach_btf_id() to check changes_pkt_data flag; - moves call to check_attach_btf_id() after the call to check_cfg(), because it needs changes_pkt_data flag to be set: bpf_check: ... ... - check_attach_btf_id resolve_pseudo_ldimm64 resolve_pseudo_ldimm64 --> bpf_prog_is_offloaded bpf_prog_is_offloaded check_cfg check_cfg + check_attach_btf_id ... ... The following fields are set by check_attach_btf_id(): - env->ops - prog->aux->attach_btf_trace - prog->aux->attach_func_name - prog->aux->attach_func_proto - prog->aux->dst_trampoline - prog->aux->mod - prog->aux->saved_dst_attach_type - prog->aux->saved_dst_prog_type - prog->expected_attach_type Neither of these fields are used by resolve_pseudo_ldimm64() or bpf_prog_offload_verifier_prep() (for netronome and netdevsim drivers), so the reordering is safe. Suggested-by: Alexei Starovoitov Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20241210041100.1898468-6-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov [ shung-hsi.yu: adapt to missing fields in "struct bpf_prog_aux". Context difference in jit_subprogs() because BPF Exception is not supported. Context difference in bpf_check() because commit 5b5f51bff1b6 "bpf: no_caller_saved_registers attribute for helper calls" is not present. ] Signed-off-by: Shung-Hsi Yu Signed-off-by: Greg Kroah-Hartman

bpf: Fix theoretical prog_array UAF in __uprobe_perf_func()

2024-12-19T17:11:25+00:00

commit 7d0d673627e20cfa3b21a829a896ce03b58a4f1c upstream. Currently, the pointer stored in call->prog_array is loaded in __uprobe_perf_func(), with no RCU annotation and no immediately visible RCU protection, so it looks as if the loaded pointer can immediately be dangling. Later, bpf_prog_run_array_uprobe() starts a RCU-trace read-side critical section, but this is too late. It then uses rcu_dereference_check(), but this use of rcu_dereference_check() does not actually dereference anything. Fix it by aligning the semantics to bpf_prog_run_array(): Let the caller provide rcu_read_lock_trace() protection and then load call->prog_array with rcu_dereference_check(). This issue seems to be theoretical: I don't know of any way to reach this code without having handle_swbp() further up the stack, which is already holding a rcu_read_lock_trace() lock, so where we take rcu_read_lock_trace() in __uprobe_perf_func()/bpf_prog_run_array_uprobe() doesn't actually have any effect. Fixes: 8c7dcb84e3b7 ("bpf: implement sleepable uprobes by chaining gps") Suggested-by: Andrii Nakryiko Signed-off-by: Jann Horn Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20241210-bpf-fix-uprobe-uaf-v4-1-5fc8959b2b74@google.com Signed-off-by: Greg Kroah-Hartman

bpf: Add MEM_WRITE attribute

2024-11-01T00:58:30+00:00

[ Upstream commit 6fad274f06f038c29660aa53fbad14241c9fd976 ] Add a MEM_WRITE attribute for BPF helper functions which can be used in bpf_func_proto to annotate an argument type in order to let the verifier know that the helper writes into the memory passed as an argument. In the past MEM_UNINIT has been (ab)used for this function, but the latter merely tells the verifier that the passed memory can be uninitialized. There have been bugs with overloading the latter but aside from that there are also cases where the passed memory is read + written which currently cannot be expressed, see also 4b3786a6c539 ("bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error"). Signed-off-by: Daniel Borkmann Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20241021152809.33343-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Stable-dep-of: 8ea607330a39 ("bpf: Fix overloading of MEM_UNINIT's meaning") Signed-off-by: Sasha Levin

bpf: Prevent tail call between progs attached to different hooks

2024-10-17T13:24:16+00:00

[ Upstream commit 28ead3eaabc16ecc907cfb71876da028080f6356 ] bpf progs can be attached to kernel functions, and the attached functions can take different parameters or return different return values. If prog attached to one kernel function tail calls prog attached to another kernel function, the ctx access or return value verification could be bypassed. For example, if prog1 is attached to func1 which takes only 1 parameter and prog2 is attached to func2 which takes two parameters. Since verifier assumes the bpf ctx passed to prog2 is constructed based on func2's prototype, verifier allows prog2 to access the second parameter from the bpf ctx passed to it. The problem is that verifier does not prevent prog1 from passing its bpf ctx to prog2 via tail call. In this case, the bpf ctx passed to prog2 is constructed from func1 instead of func2, that is, the assumption for ctx access verification is bypassed. Another example, if BPF LSM prog1 is attached to hook file_alloc_security, and BPF LSM prog2 is attached to hook bpf_lsm_audit_rule_known. Verifier knows the return value rules for these two hooks, e.g. it is legal for bpf_lsm_audit_rule_known to return positive number 1, and it is illegal for file_alloc_security to return positive number. So verifier allows prog2 to return positive number 1, but does not allow prog1 to return positive number. The problem is that verifier does not prevent prog1 from calling prog2 via tail call. In this case, prog2's return value 1 will be used as the return value for prog1's hook file_alloc_security. That is, the return value rule is bypassed. This patch adds restriction for tail call to prevent such bypasses. Signed-off-by: Xu Kuohai Link: https://lore.kernel.org/r/20240719110059.797546-4-xukuohai@huaweicloud.com Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Signed-off-by: Sasha Levin