From e3e2ae06fbfcd1b2f3de6945689ef9d9c94a2123 Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Wed, 30 Mar 2022 00:17:08 +0200 Subject: [PATCH] libelf: Also copy/convert partial datastructures in xlate functions The generated xlate functions can only convert full datastructures, dropping any trailing partial data on the floor. That means some of the data might be undefined. Just copy over the trailing bytes as is. That data isn't really usable. But at least it is defined data. https://sourceware.org/bugzilla/show_bug.cgi?id=29000 Signed-off-by: Mark Wielaard --- libelf/ChangeLog | 5 +++++ libelf/gelf_xlate.c | 10 ++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/libelf/ChangeLog b/libelf/ChangeLog index 7fd6202..299179c 100644 --- a/libelf/ChangeLog +++ b/libelf/ChangeLog @@ -1,3 +1,8 @@ +2022-03-29 Mark Wielaard + + * gelf_xlate.c (START): Define and use sz variable. + (END): Use sz variable to decide whether to do a memmove. + 2022-03-24 Mark Wielaard * elf.h: Update from glibc. diff --git a/libelf/gelf_xlate.c b/libelf/gelf_xlate.c index b9e7fd6..6f8c57b 100644 --- a/libelf/gelf_xlate.c +++ b/libelf/gelf_xlate.c @@ -1,5 +1,6 @@ /* Transformation functions for ELF data types. Copyright (C) 1998,1999,2000,2002,2004,2005,2006,2007,2015 Red Hat, Inc. + Copyright (C) 2022 Mark J. Wielaard This file is part of elfutils. Written by Ulrich Drepper , 1998. @@ -138,9 +139,14 @@ union unaligned int encode __attribute__ ((unused))) \ { ElfW2(Bits, Name) *tdest = (ElfW2(Bits, Name) *) dest; \ ElfW2(Bits, Name) *tsrc = (ElfW2(Bits, Name) *) src; \ + size_t sz = sizeof (ElfW2(Bits, Name)); \ size_t n; \ - for (n = len / sizeof (ElfW2(Bits, Name)); n > 0; ++tdest, ++tsrc, --n) { -#define END(Bits, Name) } } + for (n = len / sz; n > 0; ++tdest, ++tsrc, --n) { +#define END(Bits, Name) \ + } \ + if (len % sz > 0) /* Cannot convert partial structures, just copy. */ \ + memmove (dest, src, len % sz); \ + } #define TYPE_EXTRA(Code) #define TYPE_XLATE(Code) Code #define TYPE_NAME(Type, Name) TYPE_NAME2 (Type, Name) -- 2.7.4