From 342352caf06f2cb445596fa0eb145e38f4201d41 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Thu, 18 Jan 2024 07:06:37 -0800 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20240118150637.660461-1-jcmvbkbc@gmail.com Signed-off-by: Kees Cook Signed-off-by: Sasha Levin --- fs/binfmt_elf_fdpic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 206812ce544a..96a8b13b57d9 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -320,7 +320,7 @@ 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;