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Subject[PATCH 4.17 099/101] bpf: enforce correct alignment for instructions
Date
4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>

commit 9262478220eac908ae6e168c3df2c453c87e2da3 upstream.

After commit 9facc336876f ("bpf: reject any prog that failed read-only lock")
offsetof(struct bpf_binary_header, image) became 3 instead of 4,
breaking powerpc BPF badly, since instructions need to be word aligned.

Fixes: 9facc336876f ("bpf: reject any prog that failed read-only lock")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/filter.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -455,7 +455,9 @@ struct sock_fprog_kern {
struct bpf_binary_header {
u16 pages;
u16 locked:1;
- u8 image[];
+
+ /* Some arches need word alignment for their instructions */
+ u8 image[] __aligned(4);
};

struct bpf_prog {

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