From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- scripts/module.lds.S | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 scripts/module.lds.S (limited to 'scripts/module.lds.S') diff --git a/scripts/module.lds.S b/scripts/module.lds.S new file mode 100644 index 000000000..b62683061 --- /dev/null +++ b/scripts/module.lds.S @@ -0,0 +1,68 @@ +/* + * Common module linker script, always used when linking a module. + * Archs are free to supply their own linker scripts. ld will + * combine them automatically. + */ +#ifdef CONFIG_UNWIND_TABLES +#define DISCARD_EH_FRAME +#else +#define DISCARD_EH_FRAME *(.eh_frame) +#endif + +#include + +SECTIONS { + /DISCARD/ : { + *(.discard) + *(.discard.*) + *(.export_symbol) + *(.no_trim_symbol) + } + + __ksymtab 0 : ALIGN(8) { *(SORT(___ksymtab+*)) } + __kcrctab 0 : ALIGN(4) { *(SORT(___kcrctab+*)) } + __kflagstab 0 : ALIGN(1) { *(SORT(___kflagstab+*)) } + + .ctors 0 : ALIGN(8) { *(SORT(.ctors.*)) *(.ctors) } + .init_array 0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) } + + .altinstructions 0 : ALIGN(8) { KEEP(*(.altinstructions)) } + __bug_table 0 : ALIGN(8) { KEEP(*(__bug_table)) } + __jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) } + __ex_table 0 : ALIGN(4) { KEEP(*(__ex_table)) } + + __patchable_function_entries 0 : { *(__patchable_function_entries) } + + .init.klp_funcs 0 : ALIGN(8) { KEEP(*(.init.klp_funcs)) } + .init.klp_objects 0 : ALIGN(8) { KEEP(*(.init.klp_objects)) } + +#ifdef CONFIG_ARCH_USES_CFI_TRAPS + __kcfi_traps 0 : { KEEP(*(.kcfi_traps)) } +#endif + +#ifndef CONFIG_ARCH_WANTS_MODULES_TEXT_SECTIONS + .text 0 : { + *(.text .text.[0-9a-zA-Z_]*) + } +#endif + + .bss 0 : { + *(.bss .bss.[0-9a-zA-Z_]*) + *(.bss..L*) + } + + .data 0 : { + *(.data .data.[0-9a-zA-Z_]*) + *(.data..L*) + } + + .rodata 0 : { + *(.rodata .rodata.[0-9a-zA-Z_]*) + *(.rodata..L*) + } + + MOD_SEPARATE_CODETAG_SECTIONS() +} + +/* bring in arch-specific sections */ +#include -- cgit v1.3.1