From 25a7812cd0867043ec0a045c41e6bd3981d69bc4 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 13 Mar 2023 15:19:00 -0400 Subject: Fix JSON error reporting for many cases of erroneous string values. The majority of error exit cases in json_lex_string() failed to set lex->token_terminator, causing problems for the error context reporting code: it would see token_terminator less than token_start and do something more or less nuts. In v14 and up the end result could be as bad as a crash in report_json_context(). Older versions accidentally avoided that fate; but all versions produce error context lines that are far less useful than intended, because they'd stop at the end of the prior token instead of continuing to where the actually-bad input is. To fix, invent some macros that make it less notationally painful to do the right thing. Also add documentation about what the function is actually required to do; and in >= v14, add an assertion in report_json_context about token_terminator being sufficiently far advanced. Per report from Nikolay Shaplov. Back-patch to all supported versions. Discussion: https://postgr.es/m/7332649.x5DLKWyVIX@thinkpad-pgpro --- src/backend/utils/adt/jsonfuncs.c | 1 + 1 file changed, 1 insertion(+) (limited to 'src/backend/utils/adt/jsonfuncs.c') diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c index bdfc48cdf50..7a36f74dad4 100644 --- a/src/backend/utils/adt/jsonfuncs.c +++ b/src/backend/utils/adt/jsonfuncs.c @@ -675,6 +675,7 @@ report_json_context(JsonLexContext *lex) line_start = lex->line_start; context_start = line_start; context_end = lex->token_terminator; + Assert(context_end >= context_start); /* Advance until we are close enough to context_end */ while (context_end - context_start >= 50) -- cgit v1.2.3