[PATCH v14 6/9] powerpc/bpf: Write protect JIT code

Jordan Niethe jniethe5 at gmail.com
Mon May 17 13:28:07 AEST 2021

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

Without CONFIG_STRICT_MODULE_RWX the image will be writable and
executable until the call to bpf_jit_binary_lock_ro().

Reviewed-by: Christophe Leroy <christophe.leroy at csgroup.eu>
Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
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);

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