diff options
| author | Andrii Nakryiko | 2021-11-23 16:23:18 -0800 |
|---|---|---|
| committer | Daniel Borkmann | 2021-11-26 00:15:03 +0100 |
| commit | 593835377f24ca1bb98008ec1dc3baefe491ad6e (patch) | |
| tree | fa57f0773226c642232f84063ffc07d93250cf94 /tools/lib | |
| parent | 8cb125566c40b7141d8842c534f0ea5820ee3d5c (diff) | |
libbpf: Fix using invalidated memory in bpf_linker
add_dst_sec() can invalidate bpf_linker's section index making
dst_symtab pointer pointing into unallocated memory. Reinitialize
dst_symtab pointer on each iteration to make sure it's always valid.
Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211124002325.1737739-7-andrii@kernel.org
Diffstat (limited to 'tools/lib')
| -rw-r--r-- | tools/lib/bpf/linker.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 3e1b2a15fdc7..9aa016fb55aa 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -2000,7 +2000,7 @@ add_sym: static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *obj) { struct src_sec *src_symtab = &obj->secs[obj->symtab_sec_idx]; - struct dst_sec *dst_symtab = &linker->secs[linker->symtab_sec_idx]; + struct dst_sec *dst_symtab; int i, err; for (i = 1; i < obj->sec_cnt; i++) { @@ -2033,6 +2033,9 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob return -1; } + /* add_dst_sec() above could have invalidated linker->secs */ + dst_symtab = &linker->secs[linker->symtab_sec_idx]; + /* shdr->sh_link points to SYMTAB */ dst_sec->shdr->sh_link = linker->symtab_sec_idx; |