cdc732d657
CVE-2018-18310 (#1642605)
52 lines
2.1 KiB
Diff
52 lines
2.1 KiB
Diff
commit 20f9de9b5f704cec55df92406a50bcbcfca96acd
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Author: Mark Wielaard <mark@klomp.org>
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Date: Sun Oct 14 16:45:48 2018 +0200
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libdwfl: Sanity check partial core file data reads.
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There were two issues when reading note data from a core file.
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We didn't check if the data we already had in a buffer was big
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enough. And if we did get the data, we should check if we got
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everything, or just a part of the data.
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https://sourceware.org/bugzilla/show_bug.cgi?id=23752
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Signed-off-by: Mark Wielaard <mark@klomp.org>
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diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c
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index 36e5c82..8749884 100644
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--- a/libdwfl/dwfl_segment_report_module.c
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+++ b/libdwfl/dwfl_segment_report_module.c
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@@ -1,5 +1,5 @@
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/* Sniff out modules from ELF headers visible in memory segments.
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- Copyright (C) 2008-2012, 2014, 2015 Red Hat, Inc.
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+ Copyright (C) 2008-2012, 2014, 2015, 2018 Red Hat, Inc.
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This file is part of elfutils.
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This file is free software; you can redistribute it and/or modify
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@@ -301,7 +301,10 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
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inline bool read_portion (void **data, size_t *data_size,
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GElf_Addr vaddr, size_t filesz)
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{
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- if (vaddr - start + filesz > buffer_available
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+ /* Check whether we will have to read the segment data, or if it
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+ can be returned from the existing buffer. */
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+ if (filesz > buffer_available
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+ || vaddr - start > buffer_available - filesz
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/* If we're in string mode, then don't consider the buffer we have
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sufficient unless it contains the terminator of the string. */
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|| (filesz == 0 && memchr (vaddr - start + buffer, '\0',
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@@ -459,6 +462,12 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
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if (read_portion (&data, &data_size, vaddr, filesz))
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return;
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+ /* data_size will be zero if we got everything from the initial
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+ buffer, otherwise it will be the size of the new buffer that
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+ could be read. */
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+ if (data_size != 0)
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+ filesz = data_size;
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+
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assert (sizeof (Elf32_Nhdr) == sizeof (Elf64_Nhdr));
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void *notes;
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