Re: [PATCH 5/5] perf dso: Replace assert with runtime check in dso__read_symbol()

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Misleading error code used for bounds check failure.
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--- Patch [5]: [PATCH 5/5] perf dso: Replace assert with runtime check in dso__read_symbol() ---
commit 99fef42823fa80b278999b8901d74d88e812bd2a
Author: Arnaldo Carvalho de Melo <[email protected]>

perf dso: Replace assert with runtime check in dso__read_symbol()

This commit replaces an assert in dso__read_symbol() with a runtime bounds
check to prevent out-of-bounds heap reads or assertion failures when processing
untrusted perf.data files.

> diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> index 4dd64069c4348..42bfe30a3b518 100644
> --- a/tools/perf/util/dso.c
> +++ b/tools/perf/util/dso.c
> @@ -2038,7 +2038,12 @@ const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename,
>  			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
>  			return NULL;
>  		}
> -		assert(len <= info_linear->info.jited_prog_len);
> +		if (len > info_linear->info.jited_prog_len) {
> +			pr_debug("BPF symbol length %zu exceeds jited_prog_len %u\n",
> +				 len, info_linear->info.jited_prog_len);
> +			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;

[Severity: Medium]
Since this is a bounds check failure in dso__read_symbol() triggered by a
corrupted perf.data file, reusing SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF might
cause tools to incorrectly report that the BPF file is missing its BTF section
instead of indicating a length mismatch.

Could this regression result in a confusing message for the user?

> +			return NULL;
> +		}
>  		*out_buf_len = len;
>  		return (const u8 *)(uintptr_t)(info_linear->info.jited_prog_insns);
>  #else

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=5