[PATCH 2/3] perf tools: Make the JSON parser more conformant when in strict mode
From: James Clark <hidden>
Date: 2021-10-07 11:06:21
Also in:
linux-perf-users, lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
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 Signed-off-by: James Clark <redacted> --- tools/perf/pmu-events/jsmn.c | 42 ++++++++++++++++++++++++++++++++++-- 1 file changed, 40 insertions(+), 2 deletions(-)
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 } /*
--
2.28.0
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