[PATCH] fs/binfmt_elf: fix PT_LOAD p_align values for loaders

From: Mike Rapoport
Date: Wed Feb 02 2022 - 07:14:44 EST


From: Mike Rapoport <rppt@xxxxxxxxxxxxx>

Rui Salvaterra reported that Aisleroit solitaire crashes with "Wrong
__data_start/_end pair" assertion from libgc after update to v5.17-rc1.

Bisection pointed to commit 9630f0d60fec ("fs/binfmt_elf: use PT_LOAD
p_align values for static PIE") that fixed handling of static PIEs, but
made the condition that guards load_bias calculation to exclude loader
binaries.

Restoring the check for presence of interpreter fixes the problem.

Fixes: 9630f0d60fec ("fs/binfmt_elf: use PT_LOAD p_align values for static PIE")
Reported-by: Rui Salvaterra <rsalvaterra@xxxxxxxxx>
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
---
fs/binfmt_elf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 605017eb9349..9e11e6f13e83 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1117,7 +1117,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
* without MAP_FIXED nor MAP_FIXED_NOREPLACE).
*/
alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum);
- if (alignment > ELF_MIN_ALIGN) {
+ if (interpreter || alignment > ELF_MIN_ALIGN) {
load_bias = ELF_ET_DYN_BASE;
if (current->flags & PF_RANDOMIZE)
load_bias += arch_mmap_rnd();
--
2.34.1