From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>
Subject: [PATCH bpf-next 06/13] libbpf: fix using invalidated memory in bpf_linker
Date: Tue, 23 Nov 2021 16:23:18 -0800 [thread overview]
Message-ID: <20211124002325.1737739-7-andrii@kernel.org> (raw)
In-Reply-To: <20211124002325.1737739-1-andrii@kernel.org>
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>
---
tools/lib/bpf/linker.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
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 @@ static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj,
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;
--
2.30.2
next prev parent reply other threads:[~2021-11-24 0:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 0:23 [PATCH bpf-next 00/13] Fix sanitizer-reported libbpf and selftest issues Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 01/13] tools/resolve_btf_ids: close ELF file on error Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 02/13] libbpf: fix potential misaligned memory access in btf_ext__new() Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 03/13] libbpf: prevent UBSan from complaining about integer overflow Andrii Nakryiko
2021-11-25 22:21 ` Daniel Borkmann
2021-11-25 23:19 ` Daniel Borkmann
2021-11-26 1:23 ` Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 04/13] libbpf: don't call libc APIs with NULL pointers Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 05/13] libbpf: fix glob_syms memory leak in bpf_linker Andrii Nakryiko
2021-11-24 0:23 ` Andrii Nakryiko [this message]
2021-11-24 0:23 ` [PATCH bpf-next 07/13] selftests/bpf: fix UBSan complaint about signed __int128 overflow Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 08/13] selftests/bpf: fix possible NULL passed to memcpy() with zero size Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 09/13] selftests/bpf: prevent misaligned memory access in get_stack_raw_tp test Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 10/13] selftests/bpf: fix misaligned memory access in queue_stack_map test Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 11/13] selftests/bpf: prevent out-of-bounds stack access in test_bpffs Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 12/13] selftests/bpf: fix misaligned memory accesses in xdp_bonding test Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 13/13] selftests/bpf: fix misaligned accesses in xdp and xdp_bpf2bpf tests Andrii Nakryiko
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