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1// SPDX-License-Identifier: GPL-2.02/*3 * fs/partitions/amiga.c4 *5 * Code extracted from drivers/block/genhd.c6 *7 * Copyright (C) 1991-1998 Linus Torvalds8 * Re-organised Feb 1998 Russell King9 */10 11#define pr_fmt(fmt) fmt12 13#include <linux/types.h>14#include <linux/mm_types.h>15#include <linux/overflow.h>16#include <linux/affs_hardblocks.h>17 18#include "check.h"19 20/* magic offsets in partition DosEnvVec */21#define NR_HD 322#define NR_SECT 523#define LO_CYL 924#define HI_CYL 1025 26static __inline__ u3227checksum_block(__be32 *m, int size)28{29 u32 sum = 0;30 31 while (size--)32 sum += be32_to_cpu(*m++);33 return sum;34}35 36int amiga_partition(struct parsed_partitions *state)37{38 Sector sect;39 unsigned char *data;40 struct RigidDiskBlock *rdb;41 struct PartitionBlock *pb;42 u64 start_sect, nr_sects;43 sector_t blk, end_sect;44 u32 cylblk; /* rdb_CylBlocks = nr_heads*sect_per_track */45 u32 nr_hd, nr_sect, lo_cyl, hi_cyl;46 int part, res = 0;47 unsigned int blksize = 1; /* Multiplier for disk block size */48 int slot = 1;49 50 for (blk = 0; ; blk++, put_dev_sector(sect)) {51 if (blk == RDB_ALLOCATION_LIMIT)52 goto rdb_done;53 data = read_part_sector(state, blk, §);54 if (!data) {55 pr_err("Dev %s: unable to read RDB block %llu\n",56 state->disk->disk_name, blk);57 res = -1;58 goto rdb_done;59 }60 if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK))61 continue;62 63 rdb = (struct RigidDiskBlock *)data;64 if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0)65 break;66 /* Try again with 0xdc..0xdf zeroed, Windows might have67 * trashed it.68 */69 *(__be32 *)(data+0xdc) = 0;70 if (checksum_block((__be32 *)data,71 be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {72 pr_err("Trashed word at 0xd0 in block %llu ignored in checksum calculation\n",73 blk);74 break;75 }76 77 pr_err("Dev %s: RDB in block %llu has bad checksum\n",78 state->disk->disk_name, blk);79 }80 81 /* blksize is blocks per 512 byte standard block */82 blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;83 84 {85 char tmp[7 + 10 + 1 + 1];86 87 /* Be more informative */88 snprintf(tmp, sizeof(tmp), " RDSK (%d)", blksize * 512);89 strlcat(state->pp_buf, tmp, PAGE_SIZE);90 }91 blk = be32_to_cpu(rdb->rdb_PartitionList);92 put_dev_sector(sect);93 for (part = 1; (s32) blk>0 && part<=16; part++, put_dev_sector(sect)) {94 /* Read in terms partition table understands */95 if (check_mul_overflow(blk, (sector_t) blksize, &blk)) {96 pr_err("Dev %s: overflow calculating partition block %llu! Skipping partitions %u and beyond\n",97 state->disk->disk_name, blk, part);98 break;99 }100 data = read_part_sector(state, blk, §);101 if (!data) {102 pr_err("Dev %s: unable to read partition block %llu\n",103 state->disk->disk_name, blk);104 res = -1;105 goto rdb_done;106 }107 pb = (struct PartitionBlock *)data;108 blk = be32_to_cpu(pb->pb_Next);109 if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION))110 continue;111 if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )112 continue;113 114 /* RDB gives us more than enough rope to hang ourselves with,115 * many times over (2^128 bytes if all fields max out).116 * Some careful checks are in order, so check for potential117 * overflows.118 * We are multiplying four 32 bit numbers to one sector_t!119 */120 121 nr_hd = be32_to_cpu(pb->pb_Environment[NR_HD]);122 nr_sect = be32_to_cpu(pb->pb_Environment[NR_SECT]);123 124 /* CylBlocks is total number of blocks per cylinder */125 if (check_mul_overflow(nr_hd, nr_sect, &cylblk)) {126 pr_err("Dev %s: heads*sects %u overflows u32, skipping partition!\n",127 state->disk->disk_name, cylblk);128 continue;129 }130 131 /* check for consistency with RDB defined CylBlocks */132 if (cylblk > be32_to_cpu(rdb->rdb_CylBlocks)) {133 pr_warn("Dev %s: cylblk %u > rdb_CylBlocks %u!\n",134 state->disk->disk_name, cylblk,135 be32_to_cpu(rdb->rdb_CylBlocks));136 }137 138 /* RDB allows for variable logical block size -139 * normalize to 512 byte blocks and check result.140 */141 142 if (check_mul_overflow(cylblk, blksize, &cylblk)) {143 pr_err("Dev %s: partition %u bytes per cyl. overflows u32, skipping partition!\n",144 state->disk->disk_name, part);145 continue;146 }147 148 /* Calculate partition start and end. Limit of 32 bit on cylblk149 * guarantees no overflow occurs if LBD support is enabled.150 */151 152 lo_cyl = be32_to_cpu(pb->pb_Environment[LO_CYL]);153 start_sect = ((u64) lo_cyl * cylblk);154 155 hi_cyl = be32_to_cpu(pb->pb_Environment[HI_CYL]);156 nr_sects = (((u64) hi_cyl - lo_cyl + 1) * cylblk);157 158 if (!nr_sects)159 continue;160 161 /* Warn user if partition end overflows u32 (AmigaDOS limit) */162 163 if ((start_sect + nr_sects) > UINT_MAX) {164 pr_warn("Dev %s: partition %u (%llu-%llu) needs 64 bit device support!\n",165 state->disk->disk_name, part,166 start_sect, start_sect + nr_sects);167 }168 169 if (check_add_overflow(start_sect, nr_sects, &end_sect)) {170 pr_err("Dev %s: partition %u (%llu-%llu) needs LBD device support, skipping partition!\n",171 state->disk->disk_name, part,172 start_sect, end_sect);173 continue;174 }175 176 /* Tell Kernel about it */177 178 put_partition(state,slot++,start_sect,nr_sects);179 {180 /* Be even more informative to aid mounting */181 char dostype[4];182 char tmp[42];183 184 __be32 *dt = (__be32 *)dostype;185 *dt = pb->pb_Environment[16];186 if (dostype[3] < ' ')187 snprintf(tmp, sizeof(tmp), " (%c%c%c^%c)",188 dostype[0], dostype[1],189 dostype[2], dostype[3] + '@' );190 else191 snprintf(tmp, sizeof(tmp), " (%c%c%c%c)",192 dostype[0], dostype[1],193 dostype[2], dostype[3]);194 strlcat(state->pp_buf, tmp, PAGE_SIZE);195 snprintf(tmp, sizeof(tmp), "(res %d spb %d)",196 be32_to_cpu(pb->pb_Environment[6]),197 be32_to_cpu(pb->pb_Environment[4]));198 strlcat(state->pp_buf, tmp, PAGE_SIZE);199 }200 res = 1;201 }202 strlcat(state->pp_buf, "\n", PAGE_SIZE);203 204rdb_done:205 return res;206}207