From 15fd1dc3dadb4268207fa6797e753541aca09a2a 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 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 --- 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 fefc642541cb..1920ed69279b 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;