This is a note to let you know that I've just added the patch titled
fs: binfmt_elf_efpic: don't use missing interpreter's properties
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-binfmt_elf_efpic-don-t-use-missing-interpreter-s-.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8fc2881465cd39fff94ba6c9df53844e31807fcb
Author: Max Filippov <jcmvbkbc@xxxxxxxxx>
Date: Thu Jan 18 07:06:37 2024 -0800
fs: binfmt_elf_efpic: don't use missing interpreter's properties
[ Upstream commit 15fd1dc3dadb4268207fa6797e753541aca09a2a ]
Static FDPIC executable may get an executable stack even when it has
non-executable GNU_STACK segment. This happens when STACK segment has rw
permissions, but does not specify stack size. In that case FDPIC loader
uses permissions of the interpreter's stack, and for static executables
with no interpreter it results in choosing the arch-default permissions
for the stack.
Fix that by using the interpreter's properties only when the interpreter
is actually used.
Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240118150637.660461-1-jcmvbkbc@xxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index a7c2efcd0a4a3..0dbbb3a21e6c3 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -324,7 +324,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
else
executable_stack = EXSTACK_DEFAULT;
- if (stack_size == 0) {
+ if (stack_size == 0 && interp_params.flags & ELF_FDPIC_FLAG_PRESENT) {
stack_size = interp_params.stack_size;
if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
executable_stack = EXSTACK_ENABLE_X;
