| Message ID | 6D39441BF12EF246A7ABCE6654B0235320F1971F@LEMAIL01.le.imgtec.org |
|---|---|
| State | New |
| Headers | show |
On 2 October 2014 16:02, Matthew Fortune <Matthew.Fortune@imgtec.com> wrote: > Patch updated below. Though I did remember Joseph steering me away from > an ifdef based interface while reworking this: > > https://sourceware.org/ml/libc-alpha/2014-05/msg00045.html > > Does this seem more appropriate? You could implement it using the sysdeps mechanism, e.g. see how dl-irel.h and similar headers operate. > Tested for x86_64-linux-gnu. > > Thanks, > Matthew > > * elf/dl-load.c (dl-load-stubs.h): Include. > (open_verify): Add hook for phdr check. > * elf/dl-load-stubs.h: New file. > --- > elf/dl-load-stubs.h | 32 ++++++++++++++++++++++++++++++++ > elf/dl-load.c | 6 ++++++ > 2 files changed, 38 insertions(+) > create mode 100644 elf/dl-load-stubs.h > > diff --git a/elf/dl-load-stubs.h b/elf/dl-load-stubs.h > new file mode 100644 > index 0000000..8eb671d > --- /dev/null > +++ b/elf/dl-load-stubs.h > @@ -0,0 +1,32 @@ > +/* Stub implementations for loader functions. > + Copyright (C) 2014 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +/* Provide a default implementation of elf_machine_reject_phdr_p if a port > + has not provided its own. */ > + > +#ifndef ELF_MACHINE_REJECT_PHDR_P > +/* Return true iff ELF program headers are incompatible with the running > + host. */ > +static inline bool > +elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, uint_fast16_t phnum, > + const char *buf, size_t len, int fd, > + struct link_map *map) > +{ > + return false; > +} > +#endif > diff --git a/elf/dl-load.c b/elf/dl-load.c > index 016a99c..aff3506 100644 > --- a/elf/dl-load.c > +++ b/elf/dl-load.c > @@ -31,6 +31,7 @@ > #include <sys/stat.h> > #include <sys/types.h> > #include "dynamic-link.h" > +#include "dl-load-stubs.h" > #include <abi-tag.h> > #include <stackinfo.h> > #include <caller.h> > @@ -1697,6 +1698,11 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, > } > } > > + if (__glibc_unlikely ( > + elf_machine_reject_phdr_p (phdr, ehdr->e_phnum, fbp->buf, fbp->len, > + fd, loader))) > + goto close_and_out; > + > /* Check .note.ABI-tag if present. */ > for (ph = phdr; ph < &phdr[ehdr->e_phnum]; ++ph) > if (ph->p_type == PT_NOTE && ph->p_filesz >= 32 && ph->p_align >= 4) > -- > 1.9.4
> On 2 October 2014 16:02, Matthew Fortune <Matthew.Fortune@imgtec.com> > wrote: > > Patch updated below. Though I did remember Joseph steering me away from > > an ifdef based interface while reworking this: > > > > https://sourceware.org/ml/libc-alpha/2014-05/msg00045.html > > > > Does this seem more appropriate? > > You could implement it using the sysdeps mechanism, e.g. see how > dl-irel.h and similar headers operate. Thanks. I didn't quite follow what Roland was referring to by a sysdeps file. That will be much neater. Matthew
diff --git a/elf/dl-load-stubs.h b/elf/dl-load-stubs.h new file mode 100644 index 0000000..8eb671d --- /dev/null +++ b/elf/dl-load-stubs.h @@ -0,0 +1,32 @@ +/* Stub implementations for loader functions. + Copyright (C) 2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +/* Provide a default implementation of elf_machine_reject_phdr_p if a port + has not provided its own. */ + +#ifndef ELF_MACHINE_REJECT_PHDR_P +/* Return true iff ELF program headers are incompatible with the running + host. */ +static inline bool +elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, uint_fast16_t phnum, + const char *buf, size_t len, int fd, + struct link_map *map) +{ + return false; +} +#endif diff --git a/elf/dl-load.c b/elf/dl-load.c index 016a99c..aff3506 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -31,6 +31,7 @@ #include <sys/stat.h> #include <sys/types.h> #include "dynamic-link.h" +#include "dl-load-stubs.h" #include <abi-tag.h> #include <stackinfo.h> #include <caller.h> @@ -1697,6 +1698,11 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, } } + if (__glibc_unlikely ( + elf_machine_reject_phdr_p (phdr, ehdr->e_phnum, fbp->buf, fbp->len, + fd, loader))) + goto close_and_out; + /* Check .note.ABI-tag if present. */ for (ph = phdr; ph < &phdr[ehdr->e_phnum]; ++ph) if (ph->p_type == PT_NOTE && ph->p_filesz >= 32 && ph->p_align >= 4)