grub2/0331-grub_dl_load_segments-page-align-the-tramp-GOT-areas.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Fri, 7 Apr 2023 16:56:09 +0200
Subject: [PATCH] grub_dl_load_segments(): page-align the tramp/GOT areas too
The tramp/GOT write-protection in grub_dl_set_mem_attrs() requires that
the tramp/GOT areas of the module image *not* share a page with any other
memory allocations. Page-align the tramp/GOT areas, while satisfying their
intrinsic alignment requirements too.
Fixes: 887f1d8fa976 (modules: load module sections at page-aligned addresses)
Fixes: ad1b904d325b (nx: set page permissions for loaded modules.)
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
grub-core/kern/dl.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
index 3b66fa410e..f3cdb9e0ba 100644
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -280,7 +280,9 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
grub_size_t tsize = 0, talign = 1, arch_addralign = 1;
#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
grub_size_t tramp;
+ grub_size_t tramp_align;
grub_size_t got;
+ grub_size_t got_align;
grub_err_t err;
#endif
char *ptr;
@@ -311,12 +313,18 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
err = grub_arch_dl_get_tramp_got_size (e, &tramp, &got);
if (err)
return err;
- tsize += ALIGN_UP (tramp, GRUB_ARCH_DL_TRAMP_ALIGN);
- if (talign < GRUB_ARCH_DL_TRAMP_ALIGN)
- talign = GRUB_ARCH_DL_TRAMP_ALIGN;
- tsize += ALIGN_UP (got, GRUB_ARCH_DL_GOT_ALIGN);
- if (talign < GRUB_ARCH_DL_GOT_ALIGN)
- talign = GRUB_ARCH_DL_GOT_ALIGN;
+ tramp_align = GRUB_ARCH_DL_TRAMP_ALIGN;
+ if (tramp_align < arch_addralign)
+ tramp_align = arch_addralign;
+ tsize += ALIGN_UP (tramp, tramp_align);
+ if (talign < tramp_align)
+ talign = tramp_align;
+ got_align = GRUB_ARCH_DL_GOT_ALIGN;
+ if (got_align < arch_addralign)
+ got_align = arch_addralign;
+ tsize += ALIGN_UP (got, got_align);
+ if (talign < got_align)
+ talign = got_align;
#endif
#ifdef GRUB_MACHINE_EMU
@@ -376,11 +384,11 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
}
}
#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
- ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, GRUB_ARCH_DL_TRAMP_ALIGN);
+ ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, tramp_align);
mod->tramp = ptr;
mod->trampptr = ptr;
ptr += tramp;
- ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, GRUB_ARCH_DL_GOT_ALIGN);
+ ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, got_align);
mod->got = ptr;
mod->gotptr = ptr;
ptr += got;