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/arm/nwfpe/fpopcode.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 arch/arm/nwfpe/fpopcode.c (limited to 'arch/arm/nwfpe/fpopcode.c') diff --git a/arch/arm/nwfpe/fpopcode.c b/arch/arm/nwfpe/fpopcode.c new file mode 100644 index 000000000..c680bf1bb --- /dev/null +++ b/arch/arm/nwfpe/fpopcode.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + NetWinder Floating Point Emulator + (c) Rebel.COM, 1998,1999 + + Direct questions, comments to Scott Bambrough + +*/ + +#include "fpa11.h" +#include "softfloat.h" +#include "fpopcode.h" +#include "fpsr.h" +#include "fpmodule.h" +#include "fpmodule.inl" + +#ifdef CONFIG_FPE_NWFPE_XP +const floatx80 floatx80Constant[] = { + { .high = 0x0000, .low = 0x0000000000000000ULL},/* extended 0.0 */ + { .high = 0x3fff, .low = 0x8000000000000000ULL},/* extended 1.0 */ + { .high = 0x4000, .low = 0x8000000000000000ULL},/* extended 2.0 */ + { .high = 0x4000, .low = 0xc000000000000000ULL},/* extended 3.0 */ + { .high = 0x4001, .low = 0x8000000000000000ULL},/* extended 4.0 */ + { .high = 0x4001, .low = 0xa000000000000000ULL},/* extended 5.0 */ + { .high = 0x3ffe, .low = 0x8000000000000000ULL},/* extended 0.5 */ + { .high = 0x4002, .low = 0xa000000000000000ULL},/* extended 10.0 */ +}; +#endif + +const float64 float64Constant[] = { + 0x0000000000000000ULL, /* double 0.0 */ + 0x3ff0000000000000ULL, /* double 1.0 */ + 0x4000000000000000ULL, /* double 2.0 */ + 0x4008000000000000ULL, /* double 3.0 */ + 0x4010000000000000ULL, /* double 4.0 */ + 0x4014000000000000ULL, /* double 5.0 */ + 0x3fe0000000000000ULL, /* double 0.5 */ + 0x4024000000000000ULL /* double 10.0 */ +}; + +const float32 float32Constant[] = { + 0x00000000, /* single 0.0 */ + 0x3f800000, /* single 1.0 */ + 0x40000000, /* single 2.0 */ + 0x40400000, /* single 3.0 */ + 0x40800000, /* single 4.0 */ + 0x40a00000, /* single 5.0 */ + 0x3f000000, /* single 0.5 */ + 0x41200000 /* single 10.0 */ +}; + -- cgit v1.3.1