openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

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 <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
new file mode 100644
index 000000000..4ea450a82
--- /dev/null
+++ b/drivers/char/ipmi/Makefile
@@ -0,0 +1,31 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the ipmi drivers.
+#
+
+ipmi_si-y := ipmi_si_intf.o ipmi_kcs_sm.o ipmi_smic_sm.o ipmi_bt_sm.o \
+	ipmi_si_hotmod.o ipmi_si_hardcode.o ipmi_si_platform.o \
+	ipmi_si_mem_io.o
+ipmi_si-$(CONFIG_HAS_IOPORT) += ipmi_si_port_io.o
+ipmi_si-$(CONFIG_PCI) += ipmi_si_pci.o
+ipmi_si-$(CONFIG_IPMI_LS2K) += ipmi_si_ls2k.o
+ipmi_si-$(CONFIG_PARISC) += ipmi_si_parisc.o
+
+obj-$(CONFIG_IPMI_HANDLER) += ipmi_msghandler.o
+obj-$(CONFIG_IPMI_DEVICE_INTERFACE) += ipmi_devintf.o
+obj-$(CONFIG_IPMI_SI) += ipmi_si.o
+obj-$(CONFIG_IPMI_DMI_DECODE) += ipmi_dmi.o
+obj-$(CONFIG_IPMI_PLAT_DATA) += ipmi_plat_data.o
+obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
+obj-$(CONFIG_IPMI_IPMB) += ipmi_ipmb.o
+obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
+obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
+obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
+obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o
+obj-$(CONFIG_IPMI_KCS_BMC_SERIO) += kcs_bmc_serio.o
+obj-$(CONFIG_IPMI_KCS_BMC_CDEV_IPMI) += kcs_bmc_cdev_ipmi.o
+obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
+obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
+obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
+obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
+obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o