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| author | Yonghong Song <yhs@fb.com> | 2018-09-21 10:23:16 -0700 |
|---|---|---|
| committer | Yonghong Song <yhs@fb.com> | 2018-09-21 10:23:16 -0700 |
| commit | a6d7e3af1fd342adf9f62e5246c74e4a3e02106c (patch) | |
| tree | a2a6ef1a14f4cd32ce5f4e814db9612d91dc1014 /src | |
| parent | c7ccd5b701959013d6565c8b6b5fbfe20ba46567 (diff) | |
| download | bcc-a6d7e3af1fd342adf9f62e5246c74e4a3e02106c.tar.gz | |
prevent array subscript expression if base/index is not rewritable
The following command failed:
trace.py -U 'r::_do_fork (retval == -11) "%llu", ((struct task_struct *)bpf_get_current_task())->signal->rlim[RLIMIT_NPROC].rlim_cur'
as rewriter generates code like
__data.v0 = (unsigned long long)((struct task_struct *)bpf_get_current_task())->signal->rlim[RLIMIT_NPROC))); _val; }).rlim_cur;
Let us prevent rewriting if either base or index is not rewritable and this fixed the issue.
Signed-off-by: Yonghong Song <yhs@fb.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cc/frontends/clang/b_frontend_action.cc | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/cc/frontends/clang/b_frontend_action.cc b/src/cc/frontends/clang/b_frontend_action.cc index dada311e..59ce9fac 100644 --- a/src/cc/frontends/clang/b_frontend_action.cc +++ b/src/cc/frontends/clang/b_frontend_action.cc @@ -505,6 +505,12 @@ bool ProbeVisitor::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { Expr *idx = E->getIdx(); memb_visited_.insert(E); + if (!rewriter_.isRewritable(GET_BEGINLOC(base))) + return true; + if (!rewriter_.isRewritable(GET_BEGINLOC(idx))) + return true; + + string pre, lbracket, rbracket; LangOptions opts; SourceLocation lbracket_start, lbracket_end; |