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 --- drivers/mtd/maps/solutionengine.c | 95 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 drivers/mtd/maps/solutionengine.c (limited to 'drivers/mtd/maps/solutionengine.c') diff --git a/drivers/mtd/maps/solutionengine.c b/drivers/mtd/maps/solutionengine.c new file mode 100644 index 000000000..c07f21b20 --- /dev/null +++ b/drivers/mtd/maps/solutionengine.c @@ -0,0 +1,95 @@ +/* + * Flash and EPROM on Hitachi Solution Engine and similar boards. + * + * (C) 2001 Red Hat, Inc. + * + * GPL'd + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static struct mtd_info *flash_mtd; +static struct mtd_info *eprom_mtd; + +struct map_info soleng_eprom_map = { + .name = "Solution Engine EPROM", + .size = 0x400000, + .bankwidth = 4, +}; + +struct map_info soleng_flash_map = { + .name = "Solution Engine FLASH", + .size = 0x400000, + .bankwidth = 4, +}; + +static const char * const probes[] = { "RedBoot", "cmdlinepart", NULL }; + +static int __init init_soleng_maps(void) +{ + /* First probe at offset 0 */ + soleng_flash_map.phys = 0; + soleng_flash_map.virt = (void __iomem *)P2SEGADDR(0); + soleng_eprom_map.phys = 0x01000000; + soleng_eprom_map.virt = (void __iomem *)P1SEGADDR(0x01000000); + simple_map_init(&soleng_eprom_map); + simple_map_init(&soleng_flash_map); + + printk(KERN_NOTICE "Probing for flash chips at 0x00000000:\n"); + flash_mtd = do_map_probe("cfi_probe", &soleng_flash_map); + if (!flash_mtd) { + /* Not there. Try swapping */ + printk(KERN_NOTICE "Probing for flash chips at 0x01000000:\n"); + soleng_flash_map.phys = 0x01000000; + soleng_flash_map.virt = P2SEGADDR(0x01000000); + soleng_eprom_map.phys = 0; + soleng_eprom_map.virt = P1SEGADDR(0); + flash_mtd = do_map_probe("cfi_probe", &soleng_flash_map); + if (!flash_mtd) { + /* Eep. */ + printk(KERN_NOTICE "Flash chips not detected at either possible location.\n"); + return -ENXIO; + } + } + printk(KERN_NOTICE "Solution Engine: Flash at 0x%pap, EPROM at 0x%pap\n", + &soleng_flash_map.phys, + &soleng_eprom_map.phys); + flash_mtd->owner = THIS_MODULE; + + eprom_mtd = do_map_probe("map_rom", &soleng_eprom_map); + if (eprom_mtd) { + eprom_mtd->owner = THIS_MODULE; + mtd_device_register(eprom_mtd, NULL, 0); + } + + mtd_device_parse_register(flash_mtd, probes, NULL, NULL, 0); + + return 0; +} + +static void __exit cleanup_soleng_maps(void) +{ + if (eprom_mtd) { + mtd_device_unregister(eprom_mtd); + map_destroy(eprom_mtd); + } + + mtd_device_unregister(flash_mtd); + map_destroy(flash_mtd); +} + +module_init(init_soleng_maps); +module_exit(cleanup_soleng_maps); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("David Woodhouse "); +MODULE_DESCRIPTION("MTD map driver for Hitachi SolutionEngine (and similar) boards"); + -- cgit v1.3.1