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, 33 insertions, 0 deletions

diff --git a/drivers/misc/cardreader/Kconfig b/drivers/misc/cardreader/Kconfig
new file mode 100644
index 000000000..a70700f0e
--- /dev/null
+++ b/drivers/misc/cardreader/Kconfig
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config MISC_ALCOR_PCI
+	tristate "Alcor Micro/Alcor Link PCI-E card reader"
+	depends on PCI
+	select MFD_CORE
+	help
+	  This supports for Alcor Micro PCI-Express card reader including au6601,
+	  au6621.
+	  Alcor Micro card readers support access to many types of memory cards,
+	  such as Memory Stick, Memory Stick Pro, Secure Digital and
+	  MultiMediaCard.
+
+config MISC_RTSX_PCI
+	tristate "Realtek PCI-E card reader"
+	depends on PCI
+	select MFD_CORE
+	help
+	  This supports for Realtek PCI-Express card reader including rts5209,
+	  rts5227, rts5228, rts522A, rts5229, rts5249, rts524A, rts525A, rtl8411,
+	  rts5260, rts5261, rts5264.
+	  Realtek card readers support access to many types of memory cards,
+	  such as Memory Stick, Memory Stick Pro, Secure Digital and
+	  MultiMediaCard.
+
+config MISC_RTSX_USB
+	tristate "Realtek USB card reader"
+	depends on USB
+	select MFD_CORE
+	help
+	  Select this option to get support for Realtek USB 2.0 card readers
+	  including RTS5129, RTS5139, RTS5179 and RTS5170.
+	  Realtek card reader supports access to many types of memory cards,
+	  such as Memory Stick Pro, Secure Digital and MultiMediaCard.