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This patch adds test cases for iter next method returning valid pointer, which can also used as usage examples. Currently iter next method should return valid pointer. iter_next_trusted is the correct usage and test if iter next method return valid pointer. bpf_iter_task_vma_next has KF_RET_NULL flag, so the returned pointer may be NULL. We need to check if the pointer is NULL before using it. iter_next_trusted_or_null is the incorrect usage. There is no checking before using the pointer, so it will be rejected by the verifier. iter_next_rcu and iter_next_rcu_or_null are similar test cases for KF_RCU_PROTECTED iterators. iter_next_rcu_not_trusted is used to test that the pointer returned by iter next method of KF_RCU_PROTECTED iterator cannot be passed in KF_TRUSTED_ARGS kfuncs. iter_next_ptr_mem_not_trusted is used to test that base type PTR_TO_MEM should not be combined with type flag PTR_TRUSTED. Signed-off-by: Juntong Deng <juntong.deng@outlook.com> Link: https://lore.kernel.org/r/AM6PR03MB5848709758F6922F02AF9F1F99962@AM6PR03MB5848.eurprd03.prod.outlook.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
126 lines
2.8 KiB
C
126 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "vmlinux.h"
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#include "bpf_experimental.h"
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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#include "../bpf_testmod/bpf_testmod_kfunc.h"
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char _license[] SEC("license") = "GPL";
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SEC("raw_tp/sys_enter")
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__success
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int iter_next_trusted(const void *ctx)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct bpf_iter_task_vma vma_it;
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struct vm_area_struct *vma_ptr;
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bpf_iter_task_vma_new(&vma_it, cur_task, 0);
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vma_ptr = bpf_iter_task_vma_next(&vma_it);
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if (vma_ptr == NULL)
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goto out;
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bpf_kfunc_trusted_vma_test(vma_ptr);
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out:
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bpf_iter_task_vma_destroy(&vma_it);
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return 0;
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}
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SEC("raw_tp/sys_enter")
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__failure __msg("Possibly NULL pointer passed to trusted arg0")
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int iter_next_trusted_or_null(const void *ctx)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct bpf_iter_task_vma vma_it;
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struct vm_area_struct *vma_ptr;
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bpf_iter_task_vma_new(&vma_it, cur_task, 0);
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vma_ptr = bpf_iter_task_vma_next(&vma_it);
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bpf_kfunc_trusted_vma_test(vma_ptr);
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bpf_iter_task_vma_destroy(&vma_it);
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return 0;
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}
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SEC("raw_tp/sys_enter")
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__success
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int iter_next_rcu(const void *ctx)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct bpf_iter_task task_it;
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struct task_struct *task_ptr;
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bpf_iter_task_new(&task_it, cur_task, 0);
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task_ptr = bpf_iter_task_next(&task_it);
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if (task_ptr == NULL)
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goto out;
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bpf_kfunc_rcu_task_test(task_ptr);
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out:
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bpf_iter_task_destroy(&task_it);
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return 0;
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}
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SEC("raw_tp/sys_enter")
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__failure __msg("Possibly NULL pointer passed to trusted arg0")
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int iter_next_rcu_or_null(const void *ctx)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct bpf_iter_task task_it;
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struct task_struct *task_ptr;
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bpf_iter_task_new(&task_it, cur_task, 0);
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task_ptr = bpf_iter_task_next(&task_it);
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bpf_kfunc_rcu_task_test(task_ptr);
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bpf_iter_task_destroy(&task_it);
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return 0;
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}
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SEC("raw_tp/sys_enter")
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__failure __msg("R1 must be referenced or trusted")
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int iter_next_rcu_not_trusted(const void *ctx)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct bpf_iter_task task_it;
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struct task_struct *task_ptr;
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bpf_iter_task_new(&task_it, cur_task, 0);
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task_ptr = bpf_iter_task_next(&task_it);
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if (task_ptr == NULL)
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goto out;
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bpf_kfunc_trusted_task_test(task_ptr);
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out:
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bpf_iter_task_destroy(&task_it);
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return 0;
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}
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SEC("raw_tp/sys_enter")
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__failure __msg("R1 cannot write into rdonly_mem")
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/* Message should not be 'R1 cannot write into rdonly_trusted_mem' */
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int iter_next_ptr_mem_not_trusted(const void *ctx)
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{
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struct bpf_iter_num num_it;
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int *num_ptr;
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bpf_iter_num_new(&num_it, 0, 10);
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num_ptr = bpf_iter_num_next(&num_it);
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if (num_ptr == NULL)
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goto out;
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bpf_kfunc_trusted_num_test(num_ptr);
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out:
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bpf_iter_num_destroy(&num_it);
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return 0;
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}
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