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/sysv68.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 block/partitions/sysv68.c (limited to 'block/partitions/sysv68.c') diff --git a/block/partitions/sysv68.c b/block/partitions/sysv68.c new file mode 100644 index 000000000..470e0f9de --- /dev/null +++ b/block/partitions/sysv68.c @@ -0,0 +1,92 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/partitions/sysv68.c + * + * Copyright (C) 2007 Philippe De Muyter + */ + +#include "check.h" + +/* + * Volume ID structure: on first 256-bytes sector of disk + */ + +struct volumeid { + u8 vid_unused[248]; + u8 vid_mac[8]; /* ASCII string "MOTOROLA" */ +}; + +/* + * config block: second 256-bytes sector on disk + */ + +struct dkconfig { + u8 ios_unused0[128]; + __be32 ios_slcblk; /* Slice table block number */ + __be16 ios_slccnt; /* Number of entries in slice table */ + u8 ios_unused1[122]; +}; + +/* + * combined volumeid and dkconfig block + */ + +struct dkblk0 { + struct volumeid dk_vid; + struct dkconfig dk_ios; +}; + +/* + * Slice Table Structure + */ + +struct slice { + __be32 nblocks; /* slice size (in blocks) */ + __be32 blkoff; /* block offset of slice */ +}; + + +int sysv68_partition(struct parsed_partitions *state) +{ + int i, slices; + int slot = 1; + Sector sect; + unsigned char *data; + struct dkblk0 *b; + struct slice *slice; + + data = read_part_sector(state, 0, §); + if (!data) + return -1; + + b = (struct dkblk0 *)data; + if (memcmp(b->dk_vid.vid_mac, "MOTOROLA", sizeof(b->dk_vid.vid_mac))) { + put_dev_sector(sect); + return 0; + } + slices = be16_to_cpu(b->dk_ios.ios_slccnt); + i = be32_to_cpu(b->dk_ios.ios_slcblk); + put_dev_sector(sect); + + data = read_part_sector(state, i, §); + if (!data) + return -1; + + slices -= 1; /* last slice is the whole disk */ + seq_buf_printf(&state->pp_buf, "sysV68: %s(s%u)", state->name, slices); + slice = (struct slice *)data; + for (i = 0; i < slices; i++, slice++) { + if (slot == state->limit) + break; + if (be32_to_cpu(slice->nblocks)) { + put_partition(state, slot, + be32_to_cpu(slice->blkoff), + be32_to_cpu(slice->nblocks)); + seq_buf_printf(&state->pp_buf, "(s%u)", i); + } + slot++; + } + seq_buf_puts(&state->pp_buf, "\n"); + put_dev_sector(sect); + return 1; +} -- cgit v1.3.1