From 676b2daabaf9a993db0e02a5ce79b984aaa0388b Mon Sep 17 00:00:00 2001 From: Song Liu Date: Wed, 2 Mar 2022 09:51:26 -0800 Subject: [PATCH] bpf, x86: Set header->size properly before freeing it On do_jit failure path, the header is freed by bpf_jit_binary_pack_free. While bpf_jit_binary_pack_free doesn't require proper ro_header->size, bpf_prog_pack_free still uses it. Set header->size in bpf_int_jit_compile before calling bpf_jit_binary_pack_free. Fixes: 1022a5498f6f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc") Fixes: 33c9805860e5 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]") Reported-by: Kui-Feng Lee Signed-off-by: Song Liu Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20220302175126.247459-3-song@kernel.org --- arch/x86/net/bpf_jit_comp.c | 5 ++++- kernel/bpf/core.c | 9 ++++++--- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index c7db0fe4de2f..e6ff8f4f9ea4 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2330,8 +2330,11 @@ skip_init_addrs: if (proglen <= 0) { out_image: image = NULL; - if (header) + if (header) { + bpf_arch_text_copy(&header->size, &rw_header->size, + sizeof(rw_header->size)); bpf_jit_binary_pack_free(header, rw_header); + } prog = orig_prog; goto out_addrs; } diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index ebb0193d07f0..ab630f773ec1 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1112,13 +1112,16 @@ int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, * 1) when the program is freed after; * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). * For case 2), we need to free both the RO memory and the RW buffer. - * Also, ro_header->size in 2) is not properly set yet, so rw_header->size - * is used for uncharge. + * + * bpf_jit_binary_pack_free requires proper ro_header->size. However, + * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size + * must be set with either bpf_jit_binary_pack_finalize (normal path) or + * bpf_arch_text_copy (when jit fails). */ void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, struct bpf_binary_header *rw_header) { - u32 size = rw_header ? rw_header->size : ro_header->size; + u32 size = ro_header->size; bpf_prog_pack_free(ro_header); kvfree(rw_header); -- 2.20.1