From a54dfbee1f1bad431793968918bbb8541dc860a0 Mon Sep 17 00:00:00 2001 From: Noah Misch Date: Mon, 9 Nov 2020 07:32:09 -0800 Subject: Ignore attempts to \gset into specially treated variables. If an interactive psql session used \gset when querying a compromised server, the attacker could execute arbitrary code as the operating system account running psql. Using a prefix not found among specially treated variables, e.g. every lowercase string, precluded the attack. Fix by issuing a warning and setting no variable for the column in question. Users wanting the old behavior can use a prefix and then a meta-command like "\set HISTSIZE :prefix_HISTSIZE". Back-patch to 9.5 (all supported versions). Reviewed by Robert Haas. Reported by Nick Cleaton. Security: CVE-2020-25696 --- src/bin/psql/variables.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'src/bin/psql/variables.c') diff --git a/src/bin/psql/variables.c b/src/bin/psql/variables.c index b9a3dfad331..03d218ea129 100644 --- a/src/bin/psql/variables.c +++ b/src/bin/psql/variables.c @@ -264,6 +264,24 @@ SetVariableAssignHook(VariableSpace space, const char *name, VariableAssignHook return true; } +/* + * Return true iff the named variable has an assign hook function. + */ +bool +VariableHasHook(VariableSpace space, const char *name) +{ + struct _variable *current; + + Assert(space); + Assert(name); + + for (current = space->next; current; current = current->next) + if (strcmp(current->name, name) == 0) + return current->assign_hook != NULL; + + return false; +} + bool SetVariableBool(VariableSpace space, const char *name) { -- cgit v1.2.3