commit: d8b9a41d76de38cab079951cd494cdb491b55126 Author: Mike Frysinger <vapier <AT> gentoo <DOT> org> AuthorDate: Sun Oct 31 23:50:01 2021 +0000 Commit: Mike Frysinger <vapier <AT> gentoo <DOT> org> CommitDate: Sun Oct 31 23:50:01 2021 +0000 URL: https://gitweb.gentoo.org/proj/sandbox.git/commit/?id=d8b9a41d
libsandbox: do not use ptrace if it returns ENOSYS QEMU's linux-user does not implement ptrace for any architecture, and any attempt to call it fails with ENOSYS. Detect that scenario. Closes: https://bugs.gentoo.org/648516 Signed-off-by: Mike Frysinger <vapier <AT> gentoo.org> libsandbox/trace.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/libsandbox/trace.c b/libsandbox/trace.c index 4e01f6e..4ae58aa 100644 --- a/libsandbox/trace.c +++ b/libsandbox/trace.c @@ -584,8 +584,14 @@ static char *flatten_args(char *const argv[]) bool trace_possible(const char *filename, char *const argv[], const void *data) { - if (_trace_possible(data)) - return true; + if (_trace_possible(data)) { + /* If we're in an environment like QEMU where ptrace doesn't work, then + * don't try to use it. If ptrace does work, this should fail with ESRCH. + */ + errno = 0; + ptrace(PTRACE_CONT, 0, NULL, NULL); + return errno == ENOSYS ? false : true; + } char *args = flatten_args(argv); sb_eqawarn("Unable to trace static ELF: %s: %s\n", filename, args);
