From 5140d8e013b0d8ab560b1bb8c72e0a8b2e96ac4b Mon Sep 17 00:00:00 2001 From: Hannes Domani Date: Sat, 4 May 2024 18:55:20 +0200 Subject: Fix heap-use-after-free in index-cached with --disable-threading If threads are disabled, either by --disable-threading explicitely, or by missing std::thread support, you get the following ASAN error when loading symbols: ==7310==ERROR: AddressSanitizer: heap-use-after-free on address 0x614000002128 at pc 0x00000098794a bp 0x7ffe37e6af70 sp 0x7ffe37e6af68 READ of size 1 at 0x614000002128 thread T0 #0 0x987949 in index_cache_store_context::store() const ../../gdb/dwarf2/index-cache.c:163 #1 0x943467 in cooked_index_worker::write_to_cache(cooked_index const*, deferred_warnings*) const ../../gdb/dwarf2/cooked-index.c:601 #2 0x1705e39 in std::function::operator()() const /gcc/9/include/c++/9.2.0/bits/std_function.h:690 #3 0x1705e39 in gdb::task_group::impl::~impl() ../../gdbsupport/task-group.cc:38 0x614000002128 is located 232 bytes inside of 408-byte region [0x614000002040,0x6140000021d8) freed by thread T0 here: #0 0x7fd75ccf8ea5 in operator delete(void*, unsigned long) ../../.././libsanitizer/asan/asan_new_delete.cc:177 #1 0x9462e5 in cooked_index::index_for_writing() ../../gdb/dwarf2/cooked-index.h:689 #2 0x9462e5 in operator() ../../gdb/dwarf2/cooked-index.c:657 #3 0x9462e5 in _M_invoke /gcc/9/include/c++/9.2.0/bits/std_function.h:300 It's happening because cooked_index_worker::wait always returns true in this case, which tells cooked_index::wait it can delete the m_state cooked_index_worker member, but cooked_index_worker::write_to_cache tries to access it immediately afterwards. Fixed by making cooked_index_worker::wait only return true if desired_state is CACHE_DONE, same as if threading was enabled, so m_state will not be prematurely deleted. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31694 Approved-By: Tom Tromey --- gdb/dwarf2/cooked-index.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gdb/dwarf2/cooked-index.c b/gdb/dwarf2/cooked-index.c index 3b95c07..767f119 100644 --- a/gdb/dwarf2/cooked-index.c +++ b/gdb/dwarf2/cooked-index.c @@ -513,7 +513,7 @@ cooked_index_worker::wait (cooked_state desired_state, bool allow_quit) #else /* Without threads, all the work is done immediately on the main thread, and there is never anything to wait for. */ - done = true; + done = desired_state == cooked_state::CACHE_DONE; #endif /* CXX_STD_THREAD */ /* Only the main thread is allowed to report complaints and the -- cgit v1.1