Improve failure detection with array parsing in pg_dump

Similarly to 3636efa, the checks done in pg_dump when parsing array
values from catalogs have been too lax.  Under memory pressure, it could
be possible, though very unlikely, to finish with dumps that miss some
data like:
- Statistics for indexes
- Run-time configuration of functions
- Configuration of extensions
- Publication list for a subscription

No backpatch is done as this is not going to be a problem in practice.
For example, if an OOM causes an array parsing to fail, a follow-up code
path of pg_dump would most likely complain with an allocation failure
due to the memory pressure.

Author: Michael Paquier
Reviewed-by: Daniel Gustafsson
Discussion: https://postgr.es/m/20201111061319.GE2276@paquier.xyz

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index c68db75b97d03bbccad9d78824dea0eba9cd3935..dc1d41dd8d2380477096567bc9fc3bbd0b8e319f 100644 (file)
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -4357,13 +4357,7 @@ dumpSubscription(Archive *fout, SubscriptionInfo *subinfo)
 
        /* Build list of quoted publications and append them to query. */
        if (!parsePGArray(subinfo->subpublications, &pubnames, &npubnames))
-       {
-               pg_log_warning("could not parse subpublications array");
-               if (pubnames)
-                       free(pubnames);
-               pubnames = NULL;
-               npubnames = 0;
-       }
+               fatal("could not parse subpublications array");
 
        publications = createPQExpBuffer();
        for (i = 0; i < npubnames; i++)
@@ -12128,13 +12122,12 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
        if (proconfig && *proconfig)
        {
                if (!parsePGArray(proconfig, &configitems, &nconfigitems))
-               {
-                       pg_log_warning("could not parse proconfig array");
-                       if (configitems)
-                               free(configitems);
-                       configitems = NULL;
-                       nconfigitems = 0;
-               }
+                       fatal("could not parse proconfig array");
+       }
+       else
+       {
+               configitems = NULL;
+               nconfigitems = 0;
        }
 
        if (funcargs)
@@ -16453,8 +16446,8 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
                char       *indstatvals = indxinfo->indstatvals;
                char      **indstatcolsarray = NULL;
                char      **indstatvalsarray = NULL;
-               int                     nstatcols;
-               int                     nstatvals;
+               int                     nstatcols = 0;
+               int                     nstatvals = 0;
 
                if (dopt->binary_upgrade)
                        binary_upgrade_set_pg_class_oids(fout, q,
@@ -16483,12 +16476,17 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
                 * If the index has any statistics on some of its columns, generate
                 * the associated ALTER INDEX queries.
                 */
-               if (parsePGArray(indstatcols, &indstatcolsarray, &nstatcols) &&
-                       parsePGArray(indstatvals, &indstatvalsarray, &nstatvals) &&
-                       nstatcols == nstatvals)
+               if (strlen(indstatcols) != 0 || strlen(indstatvals) != 0)
                {
                        int                     j;
 
+                       if (!parsePGArray(indstatcols, &indstatcolsarray, &nstatcols))
+                               fatal("could not parse index statistic columns");
+                       if (!parsePGArray(indstatvals, &indstatvalsarray, &nstatvals))
+                               fatal("could not parse index statistic values");
+                       if (nstatcols != nstatvals)
+                               fatal("mismatched number of columns and values for index stats");
+
                        for (j = 0; j < nstatcols; j++)
                        {
                                appendPQExpBuffer(q, "ALTER INDEX %s ", qqindxname);
@@ -17938,15 +17936,20 @@ processExtensionTables(Archive *fout, ExtensionInfo extinfo[],
                char       *extcondition = curext->extcondition;
                char      **extconfigarray = NULL;
                char      **extconditionarray = NULL;
-               int                     nconfigitems;
-               int                     nconditionitems;
+               int                     nconfigitems = 0;
+               int                     nconditionitems = 0;
 
-               if (parsePGArray(extconfig, &extconfigarray, &nconfigitems) &&
-                       parsePGArray(extcondition, &extconditionarray, &nconditionitems) &&
-                       nconfigitems == nconditionitems)
+               if (strlen(extconfig) != 0 || strlen(extcondition) != 0)
                {
                        int                     j;
 
+                       if (!parsePGArray(extconfig, &extconfigarray, &nconfigitems))
+                               fatal("could not parse extension configuration array");
+                       if (!parsePGArray(extcondition, &extconditionarray, &nconditionitems))
+                               fatal("could not parse extension condition array");
+                       if (nconfigitems != nconditionitems)
+                               fatal("mismatched number of configurations and conditions for extension");
+
                        for (j = 0; j < nconfigitems; j++)
                        {
                                TableInfo  *configtbl;