bpf: verbose jump offset overflow check
Larger programs may trigger 16-bit jump offset overflow check during instruction patching. Make this error verbose otherwise users cannot decipher error code without printks in the verifier. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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committed by
Daniel Borkmann

parent
71dde681a8
commit
4f73379ec5
@@ -438,6 +438,7 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
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u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
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const u32 cnt_max = S16_MAX;
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struct bpf_prog *prog_adj;
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int err;
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/* Since our patchlet doesn't expand the image, we're done. */
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if (insn_delta == 0) {
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@@ -453,8 +454,8 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
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* we afterwards may not fail anymore.
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*/
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if (insn_adj_cnt > cnt_max &&
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bpf_adj_branches(prog, off, off + 1, off + len, true))
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return NULL;
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(err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
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return ERR_PTR(err);
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/* Several new instructions need to be inserted. Make room
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* for them. Likely, there's no need for a new allocation as
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@@ -463,7 +464,7 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
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prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
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GFP_USER);
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if (!prog_adj)
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return NULL;
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return ERR_PTR(-ENOMEM);
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prog_adj->len = insn_adj_cnt;
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@@ -1096,13 +1097,13 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
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continue;
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tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
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if (!tmp) {
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if (IS_ERR(tmp)) {
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/* Patching may have repointed aux->prog during
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* realloc from the original one, so we need to
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* fix it up here on error.
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*/
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bpf_jit_prog_release_other(prog, clone);
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return ERR_PTR(-ENOMEM);
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return tmp;
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}
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clone = tmp;
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