[1/3] elf: Remove excessive p_align check on PT_LOAD segments [BZ #28688]
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Commit Message
p_align does not have to be a multiple of the page size. Only PT_LOAD
segment layout should be aligned to the page size.
1: Remove p_align check against the page size.
2. Use the page size, instead of p_align, to check PT_LOAD segment layout.
---
elf/dl-load.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
Comments
* H. J. Lu:
> p_align does not have to be a multiple of the page size. Only PT_LOAD
> segment layout should be aligned to the page size.
>
> 1: Remove p_align check against the page size.
> 2. Use the page size, instead of p_align, to check PT_LOAD segment layout.
> ---
> elf/dl-load.c | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index e61515771a..8d89ab81d1 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -1134,16 +1134,11 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> case PT_LOAD:
> /* A load command tells us to map in part of the file.
> We record the load commands and process them all later. */
> - if (__glibc_unlikely ((ph->p_align & (GLRO(dl_pagesize) - 1)) != 0))
> - {
> - errstring = N_("ELF load command alignment not page-aligned");
> - goto lose;
> - }
> if (__glibc_unlikely (((ph->p_vaddr - ph->p_offset)
> - & (ph->p_align - 1)) != 0))
> + & (GLRO(dl_pagesize) - 1)) != 0))
> {
> errstring
> - = N_("ELF load command address/offset not properly aligned");
> + = N_("ELF load command address/offset not page-aligned");
> goto lose;
> }
It would be nice if we could include the run-time page size in the error
message, but the current structure of the code makes that quite
difficult.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Thanks,
Florian
@@ -1134,16 +1134,11 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
case PT_LOAD:
/* A load command tells us to map in part of the file.
We record the load commands and process them all later. */
- if (__glibc_unlikely ((ph->p_align & (GLRO(dl_pagesize) - 1)) != 0))
- {
- errstring = N_("ELF load command alignment not page-aligned");
- goto lose;
- }
if (__glibc_unlikely (((ph->p_vaddr - ph->p_offset)
- & (ph->p_align - 1)) != 0))
+ & (GLRO(dl_pagesize) - 1)) != 0))
{
errstring
- = N_("ELF load command address/offset not properly aligned");
+ = N_("ELF load command address/offset not page-aligned");
goto lose;
}