Catch shifts > 31 bits generated by the optimizer.

[libpcap] / optimize.c

diff --git a/optimize.c b/optimize.c
index 4c2a84c1864c590bbf493c4cef1beea8a3334090..6c6deb00d22cbc2caab8c0cbfc2796ced0f85ec7 100644 (file)
--- a/optimize.c
+++ b/optimize.c
@@ -1201,6 +1201,16 @@ opt_stmt(compiler_state_t *cstate, opt_state_t *opt_state,
                        else {
                                s->code = BPF_ALU|BPF_K|op;
                                s->k = opt_state->vmap[val[X_ATOM]].const_val;
+                               /*
+                                * XXX - we need to make up our minds
+                                * as to what integers are signed and
+                                * what integers are unsigned in BPF
+                                * programs and in our IR.
+                                */
+                               if ((op == BPF_LSH || op == BPF_RSH) &&
+                                   (s->k < 0 || s->k > 31))
+                                       opt_error(cstate, opt_state,
+                                           "shift by more than 31 bits");
                                opt_state->done = 0;
                                val[A_ATOM] =
                                        F(opt_state, s->code, val[A_ATOM], K(s->k));