diff options
| -rw-r--r-- | include/linux/bpf.h | 4 | ||||
| -rw-r--r-- | kernel/bpf/core.c | 45 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.c | 25 |
3 files changed, 52 insertions, 22 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 95a7abd0ee92..486e65e3db26 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -339,8 +339,8 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs, struct bpf_prog *old_prog); int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, - __u32 __user *prog_ids, u32 request_cnt, - __u32 __user *prog_cnt); + u32 *prog_ids, u32 request_cnt, + u32 *prog_cnt); int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, struct bpf_prog *exclude_prog, struct bpf_prog *include_prog, diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index d315b393abdd..ba03ec39efb3 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1572,13 +1572,32 @@ int bpf_prog_array_length(struct bpf_prog_array __rcu *progs) return cnt; } +static bool bpf_prog_array_copy_core(struct bpf_prog **prog, + u32 *prog_ids, + u32 request_cnt) +{ + int i = 0; + + for (; *prog; prog++) { + if (*prog == &dummy_bpf_prog.prog) + continue; + prog_ids[i] = (*prog)->aux->id; + if (++i == request_cnt) { + prog++; + break; + } + } + + return !!(*prog); +} + int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, __u32 __user *prog_ids, u32 cnt) { struct bpf_prog **prog; unsigned long err = 0; - u32 i = 0, *ids; bool nospc; + u32 *ids; /* users of this function are doing: * cnt = bpf_prog_array_length(); @@ -1595,16 +1614,7 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, return -ENOMEM; rcu_read_lock(); prog = rcu_dereference(progs)->progs; - for (; *prog; prog++) { - if (*prog == &dummy_bpf_prog.prog) - continue; - ids[i] = (*prog)->aux->id; - if (++i == cnt) { - prog++; - break; - } - } - nospc = !!(*prog); + nospc = bpf_prog_array_copy_core(prog, ids, cnt); rcu_read_unlock(); err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); kfree(ids); @@ -1683,22 +1693,25 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, } int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, - __u32 __user *prog_ids, u32 request_cnt, - __u32 __user *prog_cnt) + u32 *prog_ids, u32 request_cnt, + u32 *prog_cnt) { + struct bpf_prog **prog; u32 cnt = 0; if (array) cnt = bpf_prog_array_length(array); - if (copy_to_user(prog_cnt, &cnt, sizeof(cnt))) - return -EFAULT; + *prog_cnt = cnt; /* return early if user requested only program count or nothing to copy */ if (!request_cnt || !cnt) return 0; - return bpf_prog_array_copy_to_user(array, prog_ids, request_cnt); + /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ + prog = rcu_dereference_check(array, 1)->progs; + return bpf_prog_array_copy_core(prog, prog_ids, request_cnt) ? -ENOSPC + : 0; } static void bpf_prog_free_deferred(struct work_struct *work) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d88e96d4e12c..56ba0f2a01db 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -977,6 +977,7 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) { struct perf_event_query_bpf __user *uquery = info; struct perf_event_query_bpf query = {}; + u32 *ids, prog_cnt, ids_len; int ret; if (!capable(CAP_SYS_ADMIN)) @@ -985,16 +986,32 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) return -EINVAL; if (copy_from_user(&query, uquery, sizeof(query))) return -EFAULT; - if (query.ids_len > BPF_TRACE_MAX_PROGS) + + ids_len = query.ids_len; + if (ids_len > BPF_TRACE_MAX_PROGS) return -E2BIG; + ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); + if (!ids) + return -ENOMEM; + /* + * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which + * is required when user only wants to check for uquery->prog_cnt. + * There is no need to check for it since the case is handled + * gracefully in bpf_prog_array_copy_info. + */ mutex_lock(&bpf_event_mutex); ret = bpf_prog_array_copy_info(event->tp_event->prog_array, - uquery->ids, - query.ids_len, - &uquery->prog_cnt); + ids, + ids_len, + &prog_cnt); mutex_unlock(&bpf_event_mutex); + if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || + copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) + ret = -EFAULT; + + kfree(ids); return ret; } |