From 21813684e46df1c979f714b20b369b3474f5e933 Mon Sep 17 00:00:00 2001 From: James Clark Date: Thu, 7 Oct 2021 12:05:41 +0100 Subject: perf tools: Make the JSON parser more conformant when in strict mode Return an error when a trailing comma is found or a new item is encountered before a comma or an opening brace. This ensures that the perf JSON files conform more closely to the spec at https://www.json.org Reviewed-by: Andi Kleen Reviewed-by: Kajol Jain Signed-off-by: James Clark Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andrew.Kilroy@arm.com Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mathieu Poirier Cc: Namhyung Kim Cc: Nick.Forrington@arm.com Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20211007110543.564963-3-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/pmu-events/jsmn.c | 42 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 40 insertions(+), 2 deletions(-) (limited to 'tools') diff --git a/tools/perf/pmu-events/jsmn.c b/tools/perf/pmu-events/jsmn.c index 11d1fa18bfa5..8124d2d3ff0c 100644 --- a/tools/perf/pmu-events/jsmn.c +++ b/tools/perf/pmu-events/jsmn.c @@ -176,6 +176,14 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, jsmnerr_t r; int i; jsmntok_t *token; +#ifdef JSMN_STRICT + /* + * Keeps track of whether a new object/list/primitive is expected. New items are only + * allowed after an opening brace, comma or colon. A closing brace after a comma is not + * valid JSON. + */ + int expecting_item = 1; +#endif for (; parser->pos < len; parser->pos++) { char c; @@ -185,6 +193,10 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, switch (c) { case '{': case '[': +#ifdef JSMN_STRICT + if (!expecting_item) + return JSMN_ERROR_INVAL; +#endif token = jsmn_alloc_token(parser, tokens, num_tokens); if (token == NULL) return JSMN_ERROR_NOMEM; @@ -196,6 +208,10 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, break; case '}': case ']': +#ifdef JSMN_STRICT + if (expecting_item) + return JSMN_ERROR_INVAL; +#endif type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY); for (i = parser->toknext - 1; i >= 0; i--) { token = &tokens[i]; @@ -219,6 +235,11 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, } break; case '\"': +#ifdef JSMN_STRICT + if (!expecting_item) + return JSMN_ERROR_INVAL; + expecting_item = 0; +#endif r = jsmn_parse_string(parser, js, len, tokens, num_tokens); if (r < 0) @@ -229,11 +250,15 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, case '\t': case '\r': case '\n': - case ':': - case ',': case ' ': break; #ifdef JSMN_STRICT + case ':': + case ',': + if (expecting_item) + return JSMN_ERROR_INVAL; + expecting_item = 1; + break; /* * In strict mode primitives are: * numbers and booleans. @@ -253,6 +278,9 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, case 'f': case 'n': #else + case ':': + case ',': + break; /* * In non-strict mode every unquoted value * is a primitive. @@ -260,6 +288,12 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, /*FALL THROUGH */ default: #endif + +#ifdef JSMN_STRICT + if (!expecting_item) + return JSMN_ERROR_INVAL; + expecting_item = 0; +#endif r = jsmn_parse_primitive(parser, js, len, tokens, num_tokens); if (r < 0) @@ -282,7 +316,11 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, return JSMN_ERROR_PART; } +#ifdef JSMN_STRICT + return expecting_item ? JSMN_ERROR_INVAL : JSMN_SUCCESS; +#else return JSMN_SUCCESS; +#endif } /* -- cgit v1.2.3