From: Chuyi Zhou <zhouchuyi@bytedance.com> mainline inclusion from mainline-v6.7-rc1 commit c68a78ffe2cb4207f64fd0f4262818c728c67be0 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8335 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- This patch adds kfuncs bpf_iter_task_{new,next,destroy} which allow creation and manipulation of struct bpf_iter_task in open-coded iterator style. BPF programs can use these kfuncs or through bpf_for_each macro to iterate all processes in the system. The API design keep consistent with SEC("iter/task"). bpf_iter_task_new() accepts a specific task and iterating type which allows: 1. iterating all process in the system (BPF_TASK_ITER_ALL_PROCS) 2. iterating all threads in the system (BPF_TASK_ITER_ALL_THREADS) 3. iterating all threads of a specific task (BPF_TASK_ITER_PROC_THREADS) Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> Link: https://lore.kernel.org/r/20231018061746.111364-4-zhouchuyi@bytedance.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- kernel/bpf/helpers.c | 3 + kernel/bpf/task_iter.c | 90 +++++++++++++++++++ .../testing/selftests/bpf/bpf_experimental.h | 5 ++ 3 files changed, 98 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a698e70c0250..e6c44a165a85 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2677,6 +2677,9 @@ BTF_ID_FLAGS(func, bpf_iter_task_vma_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_iter_css_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_iter_css_task_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_css_task_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_dynptr_adjust) BTF_ID_FLAGS(func, bpf_dynptr_is_null) BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index 0a4e497dd6cc..5e9a290f868b 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -972,6 +972,96 @@ __bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it) __diag_pop(); +struct bpf_iter_task { + __u64 __opaque[3]; +} __attribute__((aligned(8))); + +struct bpf_iter_task_kern { + struct task_struct *task; + struct task_struct *pos; + unsigned int flags; +} __attribute__((aligned(8))); + +enum { + /* all process in the system */ + BPF_TASK_ITER_ALL_PROCS, + /* all threads in the system */ + BPF_TASK_ITER_ALL_THREADS, + /* all threads of a specific process */ + BPF_TASK_ITER_PROC_THREADS +}; + +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes", + "Global functions as their definitions will be in vmlinux BTF"); + +__bpf_kfunc int bpf_iter_task_new(struct bpf_iter_task *it, + struct task_struct *task, unsigned int flags) +{ + struct bpf_iter_task_kern *kit = (void *)it; + + BUILD_BUG_ON(sizeof(struct bpf_iter_task_kern) > sizeof(struct bpf_iter_task)); + BUILD_BUG_ON(__alignof__(struct bpf_iter_task_kern) != + __alignof__(struct bpf_iter_task)); + + kit->task = kit->pos = NULL; + switch (flags) { + case BPF_TASK_ITER_ALL_THREADS: + case BPF_TASK_ITER_ALL_PROCS: + case BPF_TASK_ITER_PROC_THREADS: + break; + default: + return -EINVAL; + } + + if (flags == BPF_TASK_ITER_PROC_THREADS) + kit->task = task; + else + kit->task = &init_task; + kit->pos = kit->task; + kit->flags = flags; + return 0; +} + +__bpf_kfunc struct task_struct *bpf_iter_task_next(struct bpf_iter_task *it) +{ + struct bpf_iter_task_kern *kit = (void *)it; + struct task_struct *pos; + unsigned int flags; + + flags = kit->flags; + pos = kit->pos; + + if (!pos) + return pos; + + if (flags == BPF_TASK_ITER_ALL_PROCS) + goto get_next_task; + + kit->pos = next_thread(kit->pos); + if (kit->pos == kit->task) { + if (flags == BPF_TASK_ITER_PROC_THREADS) { + kit->pos = NULL; + return pos; + } + } else + return pos; + +get_next_task: + kit->pos = next_task(kit->pos); + kit->task = kit->pos; + if (kit->pos == &init_task) + kit->pos = NULL; + + return pos; +} + +__bpf_kfunc void bpf_iter_task_destroy(struct bpf_iter_task *it) +{ +} + +__diag_pop(); + DEFINE_PER_CPU(struct mmap_unlock_irq_work, mmap_unlock_work); static void do_mmap_read_unlock(struct irq_work *entry) diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h index 1d9dc535062f..2a67e2819f01 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -177,5 +177,10 @@ extern int bpf_iter_css_task_new(struct bpf_iter_css_task *it, extern struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it) __weak __ksym; extern void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it) __weak __ksym; +struct bpf_iter_task; +extern int bpf_iter_task_new(struct bpf_iter_task *it, + struct task_struct *task, unsigned int flags) __weak __ksym; +extern struct task_struct *bpf_iter_task_next(struct bpf_iter_task *it) __weak __ksym; +extern void bpf_iter_task_destroy(struct bpf_iter_task *it) __weak __ksym; #endif -- 2.34.1