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From: Alan Modra <amodra@sourceware.org> To: bfd-cvs@sourceware.org Subject: [binutils-gdb] PR29370, infinite loop in display_debug_abbrev Date: Thu, 21 Jul 2022 04:15:54 +0000 (GMT) [thread overview] Message-ID: <20220721041554.C2659385AE67@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=695c6dfe7e85006b98c8b746f3fd5f913c94ebff commit 695c6dfe7e85006b98c8b746f3fd5f913c94ebff Author: Alan Modra <amodra@gmail.com> Date: Thu Jul 21 09:56:15 2022 +0930 PR29370, infinite loop in display_debug_abbrev The PR29370 testcase is a fuzzed object file with multiple .trace_abbrev sections. Multiple .trace_abbrev or .debug_abbrev sections are not a violation of the DWARF standard. The DWARF5 standard even gives an example of multiple .debug_abbrev sections contained in groups. Caching and lookup of processed abbrevs thus needs to be done by section and offset rather than base and offset. (Why base anyway?) Or, since section contents are kept, by a pointer into the contents. PR 29370 * dwarf.c (struct abbrev_list): Replace abbrev_base and abbrev_offset with raw field. (find_abbrev_list_by_abbrev_offset): Delete. (find_abbrev_list_by_raw_abbrev): New function. (process_abbrev_set): Set list->raw and list->next. (find_and_process_abbrev_set): Replace abbrev list lookup with new function. Don't set list abbrev_base, abbrev_offset or next. Diff: --- binutils/dwarf.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/binutils/dwarf.c b/binutils/dwarf.c index 2fc352f74c5..99fb3566994 100644 --- a/binutils/dwarf.c +++ b/binutils/dwarf.c @@ -856,8 +856,7 @@ typedef struct abbrev_list { abbrev_entry * first_abbrev; abbrev_entry * last_abbrev; - dwarf_vma abbrev_base; - dwarf_vma abbrev_offset; + unsigned char * raw; struct abbrev_list * next; unsigned char * start_of_next_abbrevs; } @@ -946,14 +945,12 @@ free_all_abbrevs (void) } static abbrev_list * -find_abbrev_list_by_abbrev_offset (dwarf_vma abbrev_base, - dwarf_vma abbrev_offset) +find_abbrev_list_by_raw_abbrev (unsigned char *raw) { abbrev_list * list; for (list = abbrev_lists; list != NULL; list = list->next) - if (list->abbrev_base == abbrev_base - && list->abbrev_offset == abbrev_offset) + if (list->raw == raw) return list; return NULL; @@ -1040,6 +1037,7 @@ process_abbrev_set (struct dwarf_section *section, abbrev_list *list = xmalloc (sizeof (*list)); list->first_abbrev = NULL; list->last_abbrev = NULL; + list->raw = start; while (start < end) { @@ -1055,6 +1053,7 @@ process_abbrev_set (struct dwarf_section *section, the caller. */ if (start == end || entry == 0) { + list->next = NULL; list->start_of_next_abbrevs = start != end ? start : NULL; return list; } @@ -1144,16 +1143,10 @@ find_and_process_abbrev_set (struct dwarf_section *section, unsigned char *end = section->start + abbrev_base + abbrev_size; abbrev_list *list = NULL; if (free_list) - list = find_abbrev_list_by_abbrev_offset (abbrev_base, abbrev_offset); + list = find_abbrev_list_by_raw_abbrev (start); if (list == NULL) { list = process_abbrev_set (section, start, end); - if (list) - { - list->abbrev_base = abbrev_base; - list->abbrev_offset = abbrev_offset; - list->next = NULL; - } if (free_list) *free_list = list; }
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