Thread (15 messages) 15 messages, 2 authors, 2021-05-10

[PATCH v12 5/8] powerpc/bpf: Write protect JIT code

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STALE1996d SUPERSEDED

From: Jordan Niethe <hidden>
Date: 2021-05-06 02:41:27
Subsystem: bpf jit for powerpc (32-bit and 64-bit), bpf [general] (safe dynamic programs and tools), linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Hari Bathini, Christophe Leroy, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Madhavan Srinivasan, Linus Torvalds

Status: Superseded by v15 (posted 2021-06-09). [go to v15]

Revision v12 (6 revisions archived).

Revisions (6)
  1. v10
  2. v11 [diff against previous]
  3. v12 current [diff against previous]
  4. v13 [diff against previous]
  5. v14 [diff against previous]
  6. v15 [diff against previous]
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().

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:
-- 
2.25.1
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