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 --- block/partitions/of.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 block/partitions/of.c (limited to 'block/partitions/of.c') diff --git a/block/partitions/of.c b/block/partitions/of.c new file mode 100644 index 000000000..53664ea06 --- /dev/null +++ b/block/partitions/of.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include "check.h" + +static int validate_of_partition(struct device_node *np, int slot) +{ + u64 offset, size; + int len; + + const __be32 *reg = of_get_property(np, "reg", &len); + int a_cells = of_n_addr_cells(np); + int s_cells = of_n_size_cells(np); + + /* Make sure reg len match the expected addr and size cells */ + if (len / sizeof(*reg) != a_cells + s_cells) + return -EINVAL; + + /* Validate offset conversion from bytes to sectors */ + offset = of_read_number(reg, a_cells); + if (offset % SECTOR_SIZE) + return -EINVAL; + + /* Validate size conversion from bytes to sectors */ + size = of_read_number(reg + a_cells, s_cells); + if (!size || size % SECTOR_SIZE) + return -EINVAL; + + return 0; +} + +static void add_of_partition(struct parsed_partitions *state, int slot, + struct device_node *np) +{ + struct partition_meta_info *info; + const char *partname; + int len; + + const __be32 *reg = of_get_property(np, "reg", &len); + int a_cells = of_n_addr_cells(np); + int s_cells = of_n_size_cells(np); + + /* Convert bytes to sector size */ + u64 offset = of_read_number(reg, a_cells) / SECTOR_SIZE; + u64 size = of_read_number(reg + a_cells, s_cells) / SECTOR_SIZE; + + put_partition(state, slot, offset, size); + + if (of_property_read_bool(np, "read-only")) + state->parts[slot].flags |= ADDPART_FLAG_READONLY; + + /* + * Follow MTD label logic, search for label property, + * fallback to node name if not found. + */ + info = &state->parts[slot].info; + partname = of_get_property(np, "label", &len); + if (!partname) + partname = of_get_property(np, "name", &len); + strscpy(info->volname, partname, sizeof(info->volname)); + + seq_buf_printf(&state->pp_buf, "(%s)", info->volname); +} + +int of_partition(struct parsed_partitions *state) +{ + struct device *ddev = disk_to_dev(state->disk); + struct device_node *np; + int slot; + + struct device_node *partitions_np = of_node_get(ddev->of_node); + + if (!partitions_np || + !of_device_is_compatible(partitions_np, "fixed-partitions")) { + of_node_put(partitions_np); + return 0; + } + + slot = 1; + /* Validate parition offset and size */ + for_each_child_of_node(partitions_np, np) { + if (validate_of_partition(np, slot)) { + of_node_put(np); + of_node_put(partitions_np); + + return -1; + } + + slot++; + } + + slot = 1; + for_each_child_of_node(partitions_np, np) { + if (slot >= state->limit) { + of_node_put(np); + break; + } + + add_of_partition(state, slot, np); + + slot++; + } + + seq_buf_puts(&state->pp_buf, "\n"); + + of_node_put(partitions_np); + return 1; +} -- cgit v1.3.1