From 6d9864d900e3651413a94e1f86a93f6a03f4dc42 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Thu, 6 Aug 2015 13:25:45 -0400 Subject: [PATCH] Fix incorrect calculation in shm_mq_receive. If some, but not all, of the length word has already been read, and the next attempt to read sees exactly the number of bytes needed to complete the length word, or fewer, then we'll incorrectly read less than all of the available data. Antonin Houska --- src/backend/storage/ipc/shm_mq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c index 126cb0751b3..e765cea5aaa 100644 --- a/src/backend/storage/ipc/shm_mq.c +++ b/src/backend/storage/ipc/shm_mq.c @@ -584,7 +584,7 @@ shm_mq_receive(shm_mq_handle *mqh, Size *nbytesp, void **datap, bool nowait) if (mqh->mqh_partial_bytes + rb > sizeof(Size)) lengthbytes = sizeof(Size) - mqh->mqh_partial_bytes; else - lengthbytes = rb - mqh->mqh_partial_bytes; + lengthbytes = rb; memcpy(&mqh->mqh_buffer[mqh->mqh_partial_bytes], rawdata, lengthbytes); mqh->mqh_partial_bytes += lengthbytes;