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 --- arch/mips/dec/tc.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 arch/mips/dec/tc.c (limited to 'arch/mips/dec/tc.c') diff --git a/arch/mips/dec/tc.c b/arch/mips/dec/tc.c new file mode 100644 index 000000000..dba583976 --- /dev/null +++ b/arch/mips/dec/tc.c @@ -0,0 +1,95 @@ +/* + * TURBOchannel architecture calls. + * + * Copyright (c) Harald Koerfgen, 1998 + * Copyright (c) 2001, 2003, 2005, 2006 Maciej W. Rozycki + * Copyright (c) 2005 James Simmons + * + * This file is subject to the terms and conditions of the GNU + * General Public License. See the file "COPYING" in the main + * directory of this archive for more details. + */ +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#include +#include +#include + +/* + * Protected read byte from TURBOchannel slot space. + */ +int tc_preadb(u8 *valp, void __iomem *addr) +{ + return get_dbe(*valp, (u8 *)addr); +} + +/* + * Get TURBOchannel bus information as specified by the spec, plus + * the slot space base address and the number of slots. + */ +int __init tc_bus_get_info(struct tc_bus *tbus) +{ + if (!dec_tc_bus) + return -ENXIO; + + memcpy(&tbus->info, rex_gettcinfo(), sizeof(tbus->info)); + tbus->slot_base = CPHYSADDR((long)rex_slot_address(0)); + + switch (mips_machtype) { + case MACH_DS5000_200: + tbus->num_tcslots = 7; + break; + case MACH_DS5000_2X0: + case MACH_DS5900: + tbus->ext_slot_base = 0x20000000; + tbus->ext_slot_size = 0x20000000; + fallthrough; + case MACH_DS5000_1XX: + tbus->num_tcslots = 3; + break; + case MACH_DS5000_XX: + tbus->num_tcslots = 2; + default: + break; + } + return 0; +} + +/* + * Get the IRQ for the specified slot. + */ +void __init tc_device_get_irq(struct tc_dev *tdev) +{ + switch (tdev->slot) { + case 0: + tdev->interrupt = dec_interrupt[DEC_IRQ_TC0]; + break; + case 1: + tdev->interrupt = dec_interrupt[DEC_IRQ_TC1]; + break; + case 2: + tdev->interrupt = dec_interrupt[DEC_IRQ_TC2]; + break; + /* + * Yuck! DS5000/200 onboard devices + */ + case 5: + tdev->interrupt = dec_interrupt[DEC_IRQ_TC5]; + break; + case 6: + tdev->interrupt = dec_interrupt[DEC_IRQ_TC6]; + break; + default: + tdev->interrupt = -1; + break; + } +} -- cgit v1.3.1