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03cc3aa6a5
It's not clear why we have 128 as minimum size, but it makes testing harder and seems unnecessary, as we carefully handle truncation scenarios and use proper snprintf variants. So remove this limitation and just enforce positive length for log buffer. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Lorenz Bauer <lmb@isovalent.com> Link: https://lore.kernel.org/bpf/20230406234205.323208-3-andrii@kernel.org
85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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* Copyright (c) 2016 Facebook
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* Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
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*/
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#include <uapi/linux/btf.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/bpf.h>
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#include <linux/bpf_verifier.h>
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bool bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log)
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{
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return log->len_total > 0 && log->len_total <= UINT_MAX >> 2 &&
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log->level && log->ubuf && !(log->level & ~BPF_LOG_MASK);
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}
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void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt,
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va_list args)
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{
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unsigned int n;
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n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args);
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WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1,
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"verifier log line truncated - local buffer too short\n");
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if (log->level == BPF_LOG_KERNEL) {
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bool newline = n > 0 && log->kbuf[n - 1] == '\n';
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pr_err("BPF: %s%s", log->kbuf, newline ? "" : "\n");
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return;
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}
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n = min(log->len_total - log->len_used - 1, n);
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log->kbuf[n] = '\0';
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if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1))
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log->len_used += n;
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else
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log->ubuf = NULL;
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}
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void bpf_vlog_reset(struct bpf_verifier_log *log, u32 new_pos)
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{
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char zero = 0;
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if (!bpf_verifier_log_needed(log))
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return;
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log->len_used = new_pos;
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if (put_user(zero, log->ubuf + new_pos))
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log->ubuf = NULL;
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}
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/* log_level controls verbosity level of eBPF verifier.
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* bpf_verifier_log_write() is used to dump the verification trace to the log,
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* so the user can figure out what's wrong with the program
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*/
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__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
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const char *fmt, ...)
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{
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va_list args;
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if (!bpf_verifier_log_needed(&env->log))
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return;
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va_start(args, fmt);
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bpf_verifier_vlog(&env->log, fmt, args);
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va_end(args);
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}
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EXPORT_SYMBOL_GPL(bpf_verifier_log_write);
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__printf(2, 3) void bpf_log(struct bpf_verifier_log *log,
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const char *fmt, ...)
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{
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va_list args;
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if (!bpf_verifier_log_needed(log))
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return;
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va_start(args, fmt);
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bpf_verifier_vlog(log, fmt, args);
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va_end(args);
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}
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EXPORT_SYMBOL_GPL(bpf_log);
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