From 110febc0148f8ab867344061d5cf95ee1e1ebb3e Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 26 Feb 2021 10:35:39 -0800 Subject: ARC: fix CONFIG_HARDENED_USERCOPY Currently enabling this triggers a warning | usercopy: Kernel memory overwrite attempt detected to kernel text (offset 155633, size 11)! | usercopy: BUG: failure at mm/usercopy.c:99/usercopy_abort()! | |gcc generated __builtin_trap |Path: /bin/busybox |CPU: 0 PID: 84 Comm: init Not tainted 5.4.22 | |[ECR ]: 0x00090005 => gcc generated __builtin_trap |[EFA ]: 0x9024fcaa |[BLINK ]: usercopy_abort+0x8a/0x8c |[ERET ]: memfd_fcntl+0x0/0x470 |[STAT32]: 0x80080802 : IE K |... |... |Stack Trace: | memfd_fcntl+0x0/0x470 | usercopy_abort+0x8a/0x8c | __check_object_size+0x10e/0x138 | copy_strings+0x1f4/0x38c | __do_execve_file+0x352/0x848 | EV_Trap+0xcc/0xd0 The issue is triggered by an allocation in "init reclaimed" region. ARC _stext emcompasses the init region (for historical reasons we wanted the init.text to be under .text as well). This however trips up __check_object_size()->check_kernel_text_object() which treats this as object bleeding into kernel text. Fix that by rezoning _stext to start from regular kernel .text and leave out .init altogether. Fixes: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/15 Reported-by: Evgeniy Didin Reviewed-by: Kees Cook Signed-off-by: Vineet Gupta --- arch/arc/kernel/vmlinux.lds.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arc/kernel') diff --git a/arch/arc/kernel/vmlinux.lds.S b/arch/arc/kernel/vmlinux.lds.S index 33ce59d91461..e2146a8da195 100644 --- a/arch/arc/kernel/vmlinux.lds.S +++ b/arch/arc/kernel/vmlinux.lds.S @@ -57,7 +57,6 @@ SECTIONS .init.ramfs : { INIT_RAM_FS } . = ALIGN(PAGE_SIZE); - _stext = .; HEAD_TEXT_SECTION INIT_TEXT_SECTION(L1_CACHE_BYTES) @@ -83,6 +82,7 @@ SECTIONS .text : { _text = .; + _stext = .; TEXT_TEXT SCHED_TEXT CPUIDLE_TEXT -- cgit v1.2.3