diff options
| -rw-r--r-- | kernel/bpf/log.c | 42 |
1 files changed, 25 insertions, 17 deletions
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index 1fae2c5d7ae4..046ddff37a76 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -12,8 +12,17 @@ static bool bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log) { - return log->len_total > 0 && log->len_total <= UINT_MAX >> 2 && - log->level && log->ubuf && !(log->level & ~BPF_LOG_MASK); + /* ubuf and len_total should both be specified (or not) together */ + if (!!log->ubuf != !!log->len_total) + return false; + /* log buf without log_level is meaningless */ + if (log->ubuf && log->level == 0) + return false; + if (log->level & ~BPF_LOG_MASK) + return false; + if (log->len_total > UINT_MAX >> 2) + return false; + return true; } int bpf_vlog_init(struct bpf_verifier_log *log, u32 log_level, @@ -89,9 +98,15 @@ void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, new_start = new_end - log->len_total; else new_start = log->start_pos; + + log->start_pos = new_start; + log->end_pos = new_end - 1; /* don't count terminating '\0' */ + + if (!log->ubuf) + return; + new_n = min(n, log->len_total); cur_pos = new_end - new_n; - div_u64_rem(cur_pos, log->len_total, &buf_start); div_u64_rem(new_end, log->len_total, &buf_end); /* new_end and buf_end are exclusive indices, so if buf_end is @@ -101,12 +116,6 @@ void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, if (buf_end == 0) buf_end = log->len_total; - log->start_pos = new_start; - log->end_pos = new_end - 1; /* don't count terminating '\0' */ - - if (!log->ubuf) - return; - /* if buf_start > buf_end, we wrapped around; * if buf_start == buf_end, then we fill ubuf completely; we * can't have buf_start == buf_end to mean that there is @@ -156,12 +165,15 @@ void bpf_vlog_reset(struct bpf_verifier_log *log, u64 new_pos) if (log->end_pos < log->start_pos) log->start_pos = log->end_pos; + if (!log->ubuf) + return; + if (log->level & BPF_LOG_FIXED) pos = log->end_pos + 1; else div_u64_rem(new_pos, log->len_total, &pos); - if (log->ubuf && pos < log->len_total && put_user(zero, log->ubuf + pos)) + if (pos < log->len_total && put_user(zero, log->ubuf + pos)) log->ubuf = NULL; } @@ -211,11 +223,6 @@ static int bpf_vlog_reverse_ubuf(struct bpf_verifier_log *log, int start, int en return 0; } -static bool bpf_vlog_truncated(const struct bpf_verifier_log *log) -{ - return log->len_max > log->len_total; -} - int bpf_vlog_finalize(struct bpf_verifier_log *log, u32 *log_size_actual) { u32 sublen; @@ -228,7 +235,7 @@ int bpf_vlog_finalize(struct bpf_verifier_log *log, u32 *log_size_actual) if (!log->ubuf) goto skip_log_rotate; /* If we never truncated log, there is nothing to move around. */ - if ((log->level & BPF_LOG_FIXED) || log->start_pos == 0) + if (log->start_pos == 0) goto skip_log_rotate; /* Otherwise we need to rotate log contents to make it start from the @@ -283,7 +290,8 @@ skip_log_rotate: if (!!log->ubuf != !!log->len_total) return -EFAULT; - if (bpf_vlog_truncated(log)) + /* did truncation actually happen? */ + if (log->ubuf && log->len_max > log->len_total) return -ENOSPC; return 0; |