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authorDaniel Borkmann <daniel@iogearbox.net>2017-01-12 11:51:33 +0100
committerDavid S. Miller <davem@davemloft.net>2017-01-12 16:00:31 +0100
commit62c7989b24dbd348c2507ee6458ebf5637d6ddb5 (patch)
tree352050f1913fae4683e564607374618338c1c773 /kernel
parentbpf: pass original insn directly to convert_ctx_access (diff)
downloadlinux-62c7989b24dbd348c2507ee6458ebf5637d6ddb5.tar.xz
linux-62c7989b24dbd348c2507ee6458ebf5637d6ddb5.zip
bpf: allow b/h/w/dw access for bpf's cb in ctx
When structs are used to store temporary state in cb[] buffer that is used with programs and among tail calls, then the generated code will not always access the buffer in bpf_w chunks. We can ease programming of it and let this act more natural by allowing for aligned b/h/w/dw sized access for cb[] ctx member. Various test cases are attached as well for the selftest suite. Potentially, this can also be reused for other program types to pass data around. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/verifier.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index df7e47244e75..d60e12c67266 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3165,10 +3165,14 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
insn = env->prog->insnsi + delta;
for (i = 0; i < insn_cnt; i++, insn++) {
- if (insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
+ if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
+ insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
+ insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
insn->code == (BPF_LDX | BPF_MEM | BPF_DW))
type = BPF_READ;
- else if (insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
+ else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
+ insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
+ insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
insn->code == (BPF_STX | BPF_MEM | BPF_DW))
type = BPF_WRITE;
else