Re: [PATCH v14 6/9] powerpc/bpf: Write protect JIT code
From: Christophe Leroy <hidden>
Date: 2021-05-17 06:40:30
Le 17/05/2021 à 05:28, Jordan Niethe a écrit :
Add the necessary call to bpf_jit_binary_lock_ro() to remove write and add exec permissions to the JIT image after it has finished being written. Without CONFIG_STRICT_MODULE_RWX the image will be writable and executable until the call to bpf_jit_binary_lock_ro().
And _with_ CONFIG_STRICT_MODULE_RWX what will happen ? It will be _writable_ but not _executable_ ?
quoted hunk ↗ jump to hunk
Reviewed-by: Christophe Leroy <redacted> Signed-off-by: Jordan Niethe <redacted> --- v10: New to series v11: Remove CONFIG_STRICT_MODULE_RWX conditional --- arch/powerpc/net/bpf_jit_comp.c | 1 + 1 file changed, 1 insertion(+)diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 6c8c268e4fe8..53aefee3fe70 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c@@ -237,6 +237,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) fp->jited_len = alloclen; bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + (bpf_hdr->pages * PAGE_SIZE)); + bpf_jit_binary_lock_ro(bpf_hdr); if (!fp->is_func || extra_pass) { bpf_prog_fill_jited_linfo(fp, addrs); out_addrs: