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From b6e1a48cca51aa246cba78e99f7e2dfa200b9d26 Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mark@klomp.org>
Date: Sun, 14 Oct 2018 16:45:48 +0200
Subject: [PATCH] libdwfl: Sanity check partial core file data reads.
There were two issues when reading note data from a core file.
We didn't check if the data we already had in a buffer was big
enough. And if we did get the data, we should check if we got
everything, or just a part of the data.
https://sourceware.org/bugzilla/show_bug.cgi?id=23752
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
libdwfl/dwfl_segment_report_module.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c
index 36e5c823..87498846 100644
--- a/libdwfl/dwfl_segment_report_module.c
+++ b/libdwfl/dwfl_segment_report_module.c
@@ -1,5 +1,5 @@
/* Sniff out modules from ELF headers visible in memory segments.
- Copyright (C) 2008-2012, 2014, 2015 Red Hat, Inc.
+ Copyright (C) 2008-2012, 2014, 2015, 2018 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
@@ -301,7 +301,10 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
inline bool read_portion (void **data, size_t *data_size,
GElf_Addr vaddr, size_t filesz)
{
- if (vaddr - start + filesz > buffer_available
+ /* Check whether we will have to read the segment data, or if it
+ can be returned from the existing buffer. */
+ if (filesz > buffer_available
+ || vaddr - start > buffer_available - filesz
/* If we're in string mode, then don't consider the buffer we have
sufficient unless it contains the terminator of the string. */
|| (filesz == 0 && memchr (vaddr - start + buffer, '\0',
@@ -459,6 +462,12 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
if (read_portion (&data, &data_size, vaddr, filesz))
return;
+ /* data_size will be zero if we got everything from the initial
+ buffer, otherwise it will be the size of the new buffer that
+ could be read. */
+ if (data_size != 0)
+ filesz = data_size;
+
assert (sizeof (Elf32_Nhdr) == sizeof (Elf64_Nhdr));
void *notes;
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