From 086c603016de5018a8baddc88a8932472e0fcd1e Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Thu, 3 Nov 2016 12:00:00 -0400 Subject: [PATCH] pageinspect: Fix unaligned struct access in GIN functions The raw page data that is passed into the functions will not be aligned at 8-byte boundaries. Casting that to a struct and accessing int64 fields will result in unaligned access. On most platforms, you get away with it, but it will result on a crash on pickier platforms such as ia64 and sparc64. --- contrib/pageinspect/ginfuncs.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/contrib/pageinspect/ginfuncs.c b/contrib/pageinspect/ginfuncs.c index 145e2ce..660d236 100644 --- a/contrib/pageinspect/ginfuncs.c +++ b/contrib/pageinspect/ginfuncs.c @@ -51,7 +51,10 @@ gin_metapage_info(PG_FUNCTION_ARGS) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("input page too small (%d bytes)", raw_page_size))); - page = VARDATA(raw_page); + + /* make a copy so that the page is properly aligned for struct access */ + page = palloc(raw_page_size); + memcpy(page, VARDATA(raw_page), raw_page_size); opaq = (GinPageOpaque) PageGetSpecialPointer(page); if (opaq->flags != GIN_META) @@ -115,7 +118,10 @@ gin_page_opaque_info(PG_FUNCTION_ARGS) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("input page too small (%d bytes)", raw_page_size))); - page = VARDATA(raw_page); + + /* make a copy so that the page is properly aligned for struct access */ + page = palloc(raw_page_size); + memcpy(page, VARDATA(raw_page), raw_page_size); opaq = (GinPageOpaque) PageGetSpecialPointer(page); @@ -195,7 +201,10 @@ gin_leafpage_items(PG_FUNCTION_ARGS) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("input page too small (%d bytes)", raw_page_size))); - page = VARDATA(raw_page); + + /* make a copy so that the page is properly aligned for struct access */ + page = palloc(raw_page_size); + memcpy(page, VARDATA(raw_page), raw_page_size); if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GinPageOpaqueData))) ereport(ERROR, -- 2.10.2