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/m68k/Kconfig.debug | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 arch/m68k/Kconfig.debug (limited to 'arch/m68k/Kconfig.debug') diff --git a/arch/m68k/Kconfig.debug b/arch/m68k/Kconfig.debug new file mode 100644 index 000000000..d036f9038 --- /dev/null +++ b/arch/m68k/Kconfig.debug @@ -0,0 +1,45 @@ +# SPDX-License-Identifier: GPL-2.0 + +config BOOTPARAM + bool "Compiled-in Kernel Boot Parameter" + +config BOOTPARAM_STRING + string "Kernel Boot Parameter" + default "console=ttyS0,19200" + depends on BOOTPARAM + +config EARLY_PRINTK + bool "Early printk" + depends on MMU_MOTOROLA + help + Write kernel log output directly to a serial port. + Where implemented, output goes to the framebuffer as well. + PROM console functionality on Sun 3x is not affected by this option. + + Pass "earlyprintk" on the kernel command line to get a + boot console. + + This is useful for kernel debugging when your machine crashes very + early, i.e. before the normal console driver is loaded. + You should normally say N here, unless you want to debug such a crash. + +if !MMU + +config FULLDEBUG + bool "Full Symbolic/Source Debugging support" + help + Enable debugging symbols on kernel build. + +config HIGHPROFILE + bool "Use fast second timer for profiling" + depends on COLDFIRE + help + Use a fast secondary clock to produce profiling information. + +config BDM_DISABLE + bool "Disable BDM signals" + depends on COLDFIRE + help + Disable the ColdFire CPU's BDM signals. + +endif -- cgit v1.3.1