elf: Check invalid hole in PT_LOAD segments [BZ #28838]

Changes in v2:

1. Update commit log.

commit 163f625cf9
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Dec 21 12:35:47 2021 -0800

    elf: Remove excessive p_align check on PT_LOAD segments [BZ #28688]

removed the p_align check against the page size.  It caused the loader
error or crash on elf/tst-p_align3 when loading elf/tst-p_alignmod3.so,
which has the invalid p_align in PT_LOAD segments, added by

commit d8d94863ef
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Dec 21 13:42:28 2021 -0800

The loader failure caused by a negative length passed to __mprotect is
random, depending on architecture and toolchain.  Update _dl_map_segments
to detect invalid holes.  This fixes BZ #28838.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
This commit is contained in:
H.J. Lu 2022-02-15 06:57:11 -08:00
parent 949ad78a18
commit 2c0915cbf5

View File

@ -112,6 +112,9 @@ _dl_map_segments (struct link_map *l, int fd,
unallocated. Then jump into the normal segment-mapping loop to
handle the portion of the segment past the end of the file
mapping. */
if (__glibc_unlikely (loadcmds[nloadcmds - 1].mapstart <
c->mapend))
return N_("ELF load command address/offset not page-aligned");
if (__glibc_unlikely
(__mprotect ((caddr_t) (l->l_addr + c->mapend),
loadcmds[nloadcmds - 1].mapstart - c->mapend,