diff options
| -rw-r--r-- | include/linux/bpf_verifier.h | 21 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 25 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/cb_refs.c | 4 |
3 files changed, 11 insertions, 39 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index d84beed92ae4..3a74033d49c4 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -265,23 +265,10 @@ struct bpf_reference_state { * is used purely to inform the user of a reference leak. */ int insn_idx; - union { - /* There can be a case like: - * main (frame 0) - * cb (frame 1) - * func (frame 3) - * cb (frame 4) - * Hence for frame 4, if callback_ref just stored boolean, it would be - * impossible to distinguish nested callback refs. Hence store the - * frameno and compare that to callback_ref in check_reference_leak when - * exiting a callback function. - */ - int callback_ref; - /* Use to keep track of the source object of a lock, to ensure - * it matches on unlock. - */ - void *ptr; - }; + /* Use to keep track of the source object of a lock, to ensure + * it matches on unlock. + */ + void *ptr; }; struct bpf_retval_range { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d55ca27dc031..9f5de8d4fbd0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1358,7 +1358,6 @@ static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx) state->refs[new_ofs].type = REF_TYPE_PTR; state->refs[new_ofs].id = id; state->refs[new_ofs].insn_idx = insn_idx; - state->refs[new_ofs].callback_ref = state->in_callback_fn ? state->frameno : 0; return id; } @@ -1392,9 +1391,6 @@ static int release_reference_state(struct bpf_func_state *state, int ptr_id) if (state->refs[i].type != REF_TYPE_PTR) continue; if (state->refs[i].id == ptr_id) { - /* Cannot release caller references in callbacks */ - if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno) - return -EINVAL; if (last_idx && i != last_idx) memcpy(&state->refs[i], &state->refs[last_idx], sizeof(*state->refs)); @@ -10267,17 +10263,10 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) caller->regs[BPF_REG_0] = *r0; } - /* callback_fn frame should have released its own additions to parent's - * reference state at this point, or check_reference_leak would - * complain, hence it must be the same as the caller. There is no need - * to copy it back. - */ - if (!callee->in_callback_fn) { - /* Transfer references to the caller */ - err = copy_reference_state(caller, callee); - if (err) - return err; - } + /* Transfer references to the caller */ + err = copy_reference_state(caller, callee); + if (err) + return err; /* for callbacks like bpf_loop or bpf_for_each_map_elem go back to callsite, * there function call logic would reschedule callback visit. If iteration @@ -10447,14 +10436,12 @@ static int check_reference_leak(struct bpf_verifier_env *env, bool exception_exi bool refs_lingering = false; int i; - if (!exception_exit && state->frameno && !state->in_callback_fn) + if (!exception_exit && state->frameno) return 0; for (i = 0; i < state->acquired_refs; i++) { if (state->refs[i].type != REF_TYPE_PTR) continue; - if (!exception_exit && state->in_callback_fn && state->refs[i].callback_ref != state->frameno) - continue; verbose(env, "Unreleased reference id=%d alloc_insn=%d\n", state->refs[i].id, state->refs[i].insn_idx); refs_lingering = true; @@ -17707,8 +17694,6 @@ static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur, return false; switch (old->refs[i].type) { case REF_TYPE_PTR: - if (old->refs[i].callback_ref != cur->refs[i].callback_ref) - return false; break; case REF_TYPE_LOCK: if (old->refs[i].ptr != cur->refs[i].ptr) diff --git a/tools/testing/selftests/bpf/prog_tests/cb_refs.c b/tools/testing/selftests/bpf/prog_tests/cb_refs.c index 3bff680de16c..c40df623a8f7 100644 --- a/tools/testing/selftests/bpf/prog_tests/cb_refs.c +++ b/tools/testing/selftests/bpf/prog_tests/cb_refs.c @@ -11,8 +11,8 @@ struct { const char *prog_name; const char *err_msg; } cb_refs_tests[] = { - { "underflow_prog", "reference has not been acquired before" }, - { "leak_prog", "Unreleased reference" }, + { "underflow_prog", "must point to scalar, or struct with scalar" }, + { "leak_prog", "Possibly NULL pointer passed to helper arg2" }, { "nested_cb", "Unreleased reference id=4 alloc_insn=2" }, /* alloc_insn=2{4,5} */ { "non_cb_transfer_ref", "Unreleased reference id=4 alloc_insn=1" }, /* alloc_insn=1{1,2} */ }; |