Disallow NaN as a value for floating-point GUCs.

 None of the code that uses GUC values is really prepared for them to
 hold NaN, but parse_real() didn't have any defense against accepting
 such a value.  Treat it the same as a syntax error.
 
 I haven't attempted to analyze the exact consequences of setting any
 of the float GUCs to NaN, but since they're quite unlikely to be good,
 this seems like a back-patchable bug fix.
 
 Note: we don't need an explicit test for +-Infinity because those will
 be rejected by existing range checks.  I added a regression test for
 that in HEAD, but not older branches because the spelling of the value
 in the error message will be platform-dependent in branches where we
 don't always use port/snprintf.c.
 
 Discussion: https://postgr.es/m/1798.1552165479@sss.pgh.pa.us
 
 

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index bb6052ab15a6aa236b4695e7b5c74435ff72e416..386f6b135f4d09c1a3efc8001fa59c50b51943ba 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -6149,6 +6149,10 @@ parse_real(const char *value, double *result)
    if (endptr == value || errno == ERANGE)
        return false;
 
+   /* reject NaN (infinities will fail range checks later) */
+   if (isnan(val))
+       return false;
+
    /* allow whitespace after number */
    while (isspace((unsigned char) *endptr))
        endptr++;

diff --git a/src/test/regress/expected/guc.out b/src/test/regress/expected/guc.out
index b0d735114511a7374689e49dcd44b08f14d5ce91..5c57a6656f55f93b2c66cbf3853374a736bf120e 100644 (file)
--- a/src/test/regress/expected/guc.out
+++ b/src/test/regress/expected/guc.out
@@ -506,6 +506,13 @@ SELECT '2006-08-13 12:34:56'::timestamptz;
  Sun Aug 13 12:34:56 2006 PDT
 (1 row)
 
+-- Test some simple error cases
+SET seq_page_cost TO 'NaN';
+ERROR:  parameter "seq_page_cost" requires a numeric value
+SET vacuum_cost_delay TO '10s';
+ERROR:  10000 is outside the valid range for parameter "vacuum_cost_delay" (0 .. 100)
+SET geqo_selection_bias TO '-infinity';
+ERROR:  -Infinity is outside the valid range for parameter "geqo_selection_bias" (1.5 .. 2)
 --
 -- Test DISCARD TEMP
 --

diff --git a/src/test/regress/sql/guc.sql b/src/test/regress/sql/guc.sql
index 3b854ac4963f8ca404218c38574768db6f3621b8..6d3fca933580c559bc36f8472a41679d328ab2f1 100644 (file)
--- a/src/test/regress/sql/guc.sql
+++ b/src/test/regress/sql/guc.sql
@@ -144,6 +144,11 @@ RESET datestyle;
 SHOW datestyle;
 SELECT '2006-08-13 12:34:56'::timestamptz;
 
+-- Test some simple error cases
+SET seq_page_cost TO 'NaN';
+SET vacuum_cost_delay TO '10s';
+SET geqo_selection_bias TO '-infinity';
+
 --
 -- Test DISCARD TEMP
 --