From b6e1a48cca51aa246cba78e99f7e2dfa200b9d26 Mon Sep 17 00:00:00 2001 From: Mark Wielaard 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 --- 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;