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-rw-r--r--src/backend/libpq/pqcomm.c12
-rw-r--r--src/backend/postmaster/postmaster.c13
-rw-r--r--src/include/libpq/libpq.h1
3 files changed, 26 insertions, 0 deletions
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 4452ea4228c..31bedac2491 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -1199,6 +1199,18 @@ pq_getstring(StringInfo s)
}
}
+/* --------------------------------
+ * pq_buffer_has_data - is any buffered data available to read?
+ *
+ * This will *not* attempt to read more data.
+ * --------------------------------
+ */
+bool
+pq_buffer_has_data(void)
+{
+ return (PqRecvPointer < PqRecvLength);
+}
+
/* --------------------------------
* pq_startmsgread - begin reading a message from the client.
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 586d6a7d3b9..661b2d037f2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -2061,6 +2061,19 @@ retry1:
if (SSLok == 'S' && secure_open_server(port) == -1)
return STATUS_ERROR;
#endif
+
+ /*
+ * At this point we should have no data already buffered. If we do,
+ * it was received before we performed the SSL handshake, so it wasn't
+ * encrypted and indeed may have been injected by a man-in-the-middle.
+ * We report this case to the client.
+ */
+ if (pq_buffer_has_data())
+ ereport(FATAL,
+ (errcode(ERRCODE_PROTOCOL_VIOLATION),
+ errmsg("received unencrypted data after SSL request"),
+ errdetail("This could be either a client-software bug or evidence of an attempted man-in-the-middle attack.")));
+
/* regular startup packet, cancel, etc packet should follow... */
/* but not another SSL negotiation request */
return ProcessStartupPacket(port, true);
diff --git a/src/include/libpq/libpq.h b/src/include/libpq/libpq.h
index fd2dd5853cc..d3cf746de39 100644
--- a/src/include/libpq/libpq.h
+++ b/src/include/libpq/libpq.h
@@ -70,6 +70,7 @@ extern int pq_getmessage(StringInfo s, int maxlen);
extern int pq_getbyte(void);
extern int pq_peekbyte(void);
extern int pq_getbyte_if_available(unsigned char *c);
+extern bool pq_buffer_has_data(void);
extern int pq_putbytes(const char *s, size_t len);
/*