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linux/block/partitions/cmdline.c
Wang YanQing 645d40952c block: add verifier for cmdline partition
I meet strange filesystem corruption issue recently, the reason
is there are overlaps partitions in cmdline partition argument.

This patch add verifier for cmdline partition, then if there are
overlaps partitions, cmdline_partition will log a warning. We don't
treat overlaps partition as a error:
"
Caizhiyong <caizhiyong@hisilicon.com> said:
Partition overlap was intentionally designed in this cmdline partition.
reference http://lists.infradead.org/pipermail/linux-mtd/2013-August/048092.html
"

Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-05 09:20:53 -06:00

158 lines
3.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013 HUAWEI
* Author: Cai Zhiyong <caizhiyong@huawei.com>
*
* Read block device partition table from the command line.
* Typically used for fixed block (eMMC) embedded devices.
* It has no MBR, so saves storage space. Bootloader can be easily accessed
* by absolute address of data on the block device.
* Users can easily change the partition.
*
* The format for the command line is just like mtdparts.
*
* For further information, see "Documentation/block/cmdline-partition.txt"
*
*/
#include <linux/cmdline-parser.h>
#include "check.h"
#include "cmdline.h"
static char *cmdline;
static struct cmdline_parts *bdev_parts;
static int add_part(int slot, struct cmdline_subpart *subpart, void *param)
{
int label_min;
struct partition_meta_info *info;
char tmp[sizeof(info->volname) + 4];
struct parsed_partitions *state = (struct parsed_partitions *)param;
if (slot >= state->limit)
return 1;
put_partition(state, slot, subpart->from >> 9,
subpart->size >> 9);
info = &state->parts[slot].info;
label_min = min_t(int, sizeof(info->volname) - 1,
sizeof(subpart->name));
strncpy(info->volname, subpart->name, label_min);
info->volname[label_min] = '\0';
snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
state->parts[slot].has_info = true;
return 0;
}
static int __init cmdline_parts_setup(char *s)
{
cmdline = s;
return 1;
}
__setup("blkdevparts=", cmdline_parts_setup);
static bool has_overlaps(sector_t from, sector_t size,
sector_t from2, sector_t size2)
{
sector_t end = from + size;
sector_t end2 = from2 + size2;
if (from >= from2 && from < end2)
return true;
if (end > from2 && end <= end2)
return true;
if (from2 >= from && from2 < end)
return true;
if (end2 > from && end2 <= end)
return true;
return false;
}
static inline void overlaps_warns_header(void)
{
pr_warn("Overlapping partitions are used in command line partitions.");
pr_warn("Don't use filesystems on overlapping partitions:");
}
static void cmdline_parts_verifier(int slot, struct parsed_partitions *state)
{
int i;
bool header = true;
for (; slot < state->limit && state->parts[slot].has_info; slot++) {
for (i = slot+1; i < state->limit && state->parts[i].has_info;
i++) {
if (has_overlaps(state->parts[slot].from,
state->parts[slot].size,
state->parts[i].from,
state->parts[i].size)) {
if (header) {
header = false;
overlaps_warns_header();
}
pr_warn("%s[%llu,%llu] overlaps with "
"%s[%llu,%llu].",
state->parts[slot].info.volname,
(u64)state->parts[slot].from << 9,
(u64)state->parts[slot].size << 9,
state->parts[i].info.volname,
(u64)state->parts[i].from << 9,
(u64)state->parts[i].size << 9);
}
}
}
}
/*
* Purpose: allocate cmdline partitions.
* Returns:
* -1 if unable to read the partition table
* 0 if this isn't our partition table
* 1 if successful
*/
int cmdline_partition(struct parsed_partitions *state)
{
sector_t disk_size;
char bdev[BDEVNAME_SIZE];
struct cmdline_parts *parts;
if (cmdline) {
if (bdev_parts)
cmdline_parts_free(&bdev_parts);
if (cmdline_parts_parse(&bdev_parts, cmdline)) {
cmdline = NULL;
return -1;
}
cmdline = NULL;
}
if (!bdev_parts)
return 0;
bdevname(state->bdev, bdev);
parts = cmdline_parts_find(bdev_parts, bdev);
if (!parts)
return 0;
disk_size = get_capacity(state->bdev->bd_disk) << 9;
cmdline_parts_set(parts, disk_size, 1, add_part, (void *)state);
cmdline_parts_verifier(1, state);
strlcat(state->pp_buf, "\n", PAGE_SIZE);
return 1;
}