On Mon, Oct 14, 2024 at 04:56:31PM GMT, Andrii Nakryiko wrote: > From memfd_secret(2) manpage: > > The memory areas backing the file created with memfd_secret(2) are > visible only to the processes that have access to the file descriptor. > The memory region is removed from the kernel page tables and only the > page tables of the processes holding the file descriptor map the > corresponding physical memory. (Thus, the pages in the region can't be > accessed by the kernel itself, so that, for example, pointers to the > region can't be passed to system calls.) > > We need to handle this special case gracefully in build ID fetching > code. Return -EACCESS whenever secretmem file is passed to build_id_parse() > family of APIs. Original report and repro can be found in [0]. > > [0] https://lore.kernel.org/bpf/ZwyG8Uro%2FSyTXAni@ly-workstation/ > > Reported-by: Yi Lai <yi1.lai@xxxxxxxxx> > Suggested-by: Shakeel Butt <shakeel.butt@xxxxxxxxx> > Fixes: de3ec364c3c3 ("lib/buildid: add single folio-based file reader abstraction") > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
