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bpf, x86: Set header->size properly before freeing it

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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: 1022a5498f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc")
Fixes: 33c9805860 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]")
Reported-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220302175126.247459-3-song@kernel.org
This commit is contained in:
Song Liu 2022-03-02 09:51:26 -08:00 committed by Alexei Starovoitov
parent eed1fcee55
commit 676b2daaba
2 changed files with 10 additions and 4 deletions
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5
arch/x86/net/bpf_jit_comp.c
View File

@ -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;
}

9
kernel/bpf/core.c
View File

@ -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);