From a8b7a1391135b63de73c1bf0e0a2f8f5dc8c6ba6 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Tue, 12 Apr 2022 14:37:24 -0400 Subject: [PATCH] gdb: fix "passing NULL to memcpy" UBsan error in dwarf2/cooked-index.c Reading a simple file compiled with : $ gcc -DONE=1 -gdwarf-4 -g3 test.c $ gcc --version gcc (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0 I get: Reading symbols from /tmp/cwd/a.out... /home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.c:332:11: runtime error: null pointer passed as argument 2, which is declared to never be null It looks like even if the size is 0 (the size of the `entries` vector is 0), we shouldn't be passing a NULL pointer to memcpy. And `entries.data ()` returns NULL. Fix that by using std::vector::insert to insert the items of entries into m_entries. I haven't checked, but it should essentially compile down to a memcpy, since the vector elements are trivially copyiable. Change-Id: I75f1c901e9b522e42e89eb5936e2c70d68eb21e5 --- gdb/dwarf2/cooked-index.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/gdb/dwarf2/cooked-index.c b/gdb/dwarf2/cooked-index.c index 784c06ea04b..b66ef5a1c64 100644 --- a/gdb/dwarf2/cooked-index.c +++ b/gdb/dwarf2/cooked-index.c @@ -327,10 +327,8 @@ cooked_index_vector::finalize () m_entries = std::move (entries); else { - size_t old_size = m_entries.size (); - m_entries.resize (m_entries.size () + entries.size ()); - memcpy (m_entries.data () + old_size, - entries.data (), entries.size () * sizeof (entries[0])); + m_entries.reserve (m_entries.size () + entries.size ()); + m_entries.insert (m_entries.end (), entries.begin (), entries.end ()); } } -- 2.30.2