ecpg: fix some minor mishandling of bad input in preprocessor.

Avoid null-pointer crash when considering a cursor declaration
that's outside any C function (a case which is useless anyway).

Ensure a cursor for a prepared statement is marked as initially
not open.  At worst, if we chanced to get not-already-zeroed memory
from malloc(), this oversight would result in failing to issue a
"cursor "foo" has been declared but not opened" warning that would
have been appropriate.

Avoid running off the end of the buffer when there are mismatched
square brackets following a variable name.  This could lead to
SIGSEGV after reaching the end of memory.

Given the lack of field complaints, none of these seem to be worth
back-patching, but let's clean them up in HEAD.

Per valgrind testing by Alexander Lakhin.

Discussion: https://postgr.es/m/[email protected]

1 files changed, 3 insertions, 0 deletions

diff --git a/src/interfaces/ecpg/preproc/variable.c b/src/interfaces/ecpg/preproc/variable.c
index 6b87d5ff3d9..a4294b8f0ff 100644
--- a/src/interfaces/ecpg/preproc/variable.c
+++ b/src/interfaces/ecpg/preproc/variable.c
@@ -216,6 +216,9 @@ find_variable(const char *name)
 					case ']':
 						count--;
 						break;
+					case '\0':
+						mmfatal(PARSE_ERROR, "unmatched brace in variable \"%s\"", name);
+						break;
 					default:
 						break;
 				}