Revision 73223e4e2e3867ebf033a5a8eb2e5df0158ccc99 authored by zhong jiang on 18 August 2017, 22:16:24 UTC, committed by Linus Torvalds on 18 August 2017, 22:32:02 UTC
I hit a use after free issue when executing trinity and repoduced it with KASAN enabled. The related call trace is as follows. BUG: KASan: use after free in SyS_get_mempolicy+0x3c8/0x960 at addr ffff8801f582d766 Read of size 2 by task syz-executor1/798 INFO: Allocated in mpol_new.part.2+0x74/0x160 age=3 cpu=1 pid=799 __slab_alloc+0x768/0x970 kmem_cache_alloc+0x2e7/0x450 mpol_new.part.2+0x74/0x160 mpol_new+0x66/0x80 SyS_mbind+0x267/0x9f0 system_call_fastpath+0x16/0x1b INFO: Freed in __mpol_put+0x2b/0x40 age=4 cpu=1 pid=799 __slab_free+0x495/0x8e0 kmem_cache_free+0x2f3/0x4c0 __mpol_put+0x2b/0x40 SyS_mbind+0x383/0x9f0 system_call_fastpath+0x16/0x1b INFO: Slab 0xffffea0009cb8dc0 objects=23 used=8 fp=0xffff8801f582de40 flags=0x200000000004080 INFO: Object 0xffff8801f582d760 @offset=5984 fp=0xffff8801f582d600 Bytes b4 ffff8801f582d750: ae 01 ff ff 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ Object ffff8801f582d760: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff8801f582d770: 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkk. Redzone ffff8801f582d778: bb bb bb bb bb bb bb bb ........ Padding ffff8801f582d8b8: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ Memory state around the buggy address: ffff8801f582d600: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801f582d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801f582d700: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fc !shared memory policy is not protected against parallel removal by other thread which is normally protected by the mmap_sem. do_get_mempolicy, however, drops the lock midway while we can still access it later. Early premature up_read is a historical artifact from times when put_user was called in this path see https://lwn.net/Articles/124754/ but that is gone since 8bccd85ffbaf ("[PATCH] Implement sys_* do_* layering in the memory policy layer."). but when we have the the current mempolicy ref count model. The issue was introduced accordingly. Fix the issue by removing the premature release. Link: http://lkml.kernel.org/r/1502950924-27521-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> [2.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent da094e4
blk-zoned.c
/*
* Zoned block device handling
*
* Copyright (c) 2015, Hannes Reinecke
* Copyright (c) 2015, SUSE Linux GmbH
*
* Copyright (c) 2016, Damien Le Moal
* Copyright (c) 2016, Western Digital
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rbtree.h>
#include <linux/blkdev.h>
static inline sector_t blk_zone_start(struct request_queue *q,
sector_t sector)
{
sector_t zone_mask = blk_queue_zone_sectors(q) - 1;
return sector & ~zone_mask;
}
/*
* Check that a zone report belongs to the partition.
* If yes, fix its start sector and write pointer, copy it in the
* zone information array and return true. Return false otherwise.
*/
static bool blkdev_report_zone(struct block_device *bdev,
struct blk_zone *rep,
struct blk_zone *zone)
{
sector_t offset = get_start_sect(bdev);
if (rep->start < offset)
return false;
rep->start -= offset;
if (rep->start + rep->len > bdev->bd_part->nr_sects)
return false;
if (rep->type == BLK_ZONE_TYPE_CONVENTIONAL)
rep->wp = rep->start + rep->len;
else
rep->wp -= offset;
memcpy(zone, rep, sizeof(struct blk_zone));
return true;
}
/**
* blkdev_report_zones - Get zones information
* @bdev: Target block device
* @sector: Sector from which to report zones
* @zones: Array of zone structures where to return the zones information
* @nr_zones: Number of zone structures in the zone array
* @gfp_mask: Memory allocation flags (for bio_alloc)
*
* Description:
* Get zone information starting from the zone containing @sector.
* The number of zone information reported may be less than the number
* requested by @nr_zones. The number of zones actually reported is
* returned in @nr_zones.
*/
int blkdev_report_zones(struct block_device *bdev,
sector_t sector,
struct blk_zone *zones,
unsigned int *nr_zones,
gfp_t gfp_mask)
{
struct request_queue *q = bdev_get_queue(bdev);
struct blk_zone_report_hdr *hdr;
unsigned int nrz = *nr_zones;
struct page *page;
unsigned int nr_rep;
size_t rep_bytes;
unsigned int nr_pages;
struct bio *bio;
struct bio_vec *bv;
unsigned int i, n, nz;
unsigned int ofst;
void *addr;
int ret;
if (!q)
return -ENXIO;
if (!blk_queue_is_zoned(q))
return -EOPNOTSUPP;
if (!nrz)
return 0;
if (sector > bdev->bd_part->nr_sects) {
*nr_zones = 0;
return 0;
}
/*
* The zone report has a header. So make room for it in the
* payload. Also make sure that the report fits in a single BIO
* that will not be split down the stack.
*/
rep_bytes = sizeof(struct blk_zone_report_hdr) +
sizeof(struct blk_zone) * nrz;
rep_bytes = (rep_bytes + PAGE_SIZE - 1) & PAGE_MASK;
if (rep_bytes > (queue_max_sectors(q) << 9))
rep_bytes = queue_max_sectors(q) << 9;
nr_pages = min_t(unsigned int, BIO_MAX_PAGES,
rep_bytes >> PAGE_SHIFT);
nr_pages = min_t(unsigned int, nr_pages,
queue_max_segments(q));
bio = bio_alloc(gfp_mask, nr_pages);
if (!bio)
return -ENOMEM;
bio->bi_bdev = bdev;
bio->bi_iter.bi_sector = blk_zone_start(q, sector);
bio_set_op_attrs(bio, REQ_OP_ZONE_REPORT, 0);
for (i = 0; i < nr_pages; i++) {
page = alloc_page(gfp_mask);
if (!page) {
ret = -ENOMEM;
goto out;
}
if (!bio_add_page(bio, page, PAGE_SIZE, 0)) {
__free_page(page);
break;
}
}
if (i == 0)
ret = -ENOMEM;
else
ret = submit_bio_wait(bio);
if (ret)
goto out;
/*
* Process the report result: skip the header and go through the
* reported zones to fixup and fixup the zone information for
* partitions. At the same time, return the zone information into
* the zone array.
*/
n = 0;
nz = 0;
nr_rep = 0;
bio_for_each_segment_all(bv, bio, i) {
if (!bv->bv_page)
break;
addr = kmap_atomic(bv->bv_page);
/* Get header in the first page */
ofst = 0;
if (!nr_rep) {
hdr = (struct blk_zone_report_hdr *) addr;
nr_rep = hdr->nr_zones;
ofst = sizeof(struct blk_zone_report_hdr);
}
/* Fixup and report zones */
while (ofst < bv->bv_len &&
n < nr_rep && nz < nrz) {
if (blkdev_report_zone(bdev, addr + ofst, &zones[nz]))
nz++;
ofst += sizeof(struct blk_zone);
n++;
}
kunmap_atomic(addr);
if (n >= nr_rep || nz >= nrz)
break;
}
*nr_zones = nz;
out:
bio_for_each_segment_all(bv, bio, i)
__free_page(bv->bv_page);
bio_put(bio);
return ret;
}
EXPORT_SYMBOL_GPL(blkdev_report_zones);
/**
* blkdev_reset_zones - Reset zones write pointer
* @bdev: Target block device
* @sector: Start sector of the first zone to reset
* @nr_sectors: Number of sectors, at least the length of one zone
* @gfp_mask: Memory allocation flags (for bio_alloc)
*
* Description:
* Reset the write pointer of the zones contained in the range
* @sector..@sector+@nr_sectors. Specifying the entire disk sector range
* is valid, but the specified range should not contain conventional zones.
*/
int blkdev_reset_zones(struct block_device *bdev,
sector_t sector, sector_t nr_sectors,
gfp_t gfp_mask)
{
struct request_queue *q = bdev_get_queue(bdev);
sector_t zone_sectors;
sector_t end_sector = sector + nr_sectors;
struct bio *bio;
int ret;
if (!q)
return -ENXIO;
if (!blk_queue_is_zoned(q))
return -EOPNOTSUPP;
if (end_sector > bdev->bd_part->nr_sects)
/* Out of range */
return -EINVAL;
/* Check alignment (handle eventual smaller last zone) */
zone_sectors = blk_queue_zone_sectors(q);
if (sector & (zone_sectors - 1))
return -EINVAL;
if ((nr_sectors & (zone_sectors - 1)) &&
end_sector != bdev->bd_part->nr_sects)
return -EINVAL;
while (sector < end_sector) {
bio = bio_alloc(gfp_mask, 0);
bio->bi_iter.bi_sector = sector;
bio->bi_bdev = bdev;
bio_set_op_attrs(bio, REQ_OP_ZONE_RESET, 0);
ret = submit_bio_wait(bio);
bio_put(bio);
if (ret)
return ret;
sector += zone_sectors;
/* This may take a while, so be nice to others */
cond_resched();
}
return 0;
}
EXPORT_SYMBOL_GPL(blkdev_reset_zones);
/**
* BLKREPORTZONE ioctl processing.
* Called from blkdev_ioctl.
*/
int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
struct request_queue *q;
struct blk_zone_report rep;
struct blk_zone *zones;
int ret;
if (!argp)
return -EINVAL;
q = bdev_get_queue(bdev);
if (!q)
return -ENXIO;
if (!blk_queue_is_zoned(q))
return -ENOTTY;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (copy_from_user(&rep, argp, sizeof(struct blk_zone_report)))
return -EFAULT;
if (!rep.nr_zones)
return -EINVAL;
zones = kcalloc(rep.nr_zones, sizeof(struct blk_zone), GFP_KERNEL);
if (!zones)
return -ENOMEM;
ret = blkdev_report_zones(bdev, rep.sector,
zones, &rep.nr_zones,
GFP_KERNEL);
if (ret)
goto out;
if (copy_to_user(argp, &rep, sizeof(struct blk_zone_report))) {
ret = -EFAULT;
goto out;
}
if (rep.nr_zones) {
if (copy_to_user(argp + sizeof(struct blk_zone_report), zones,
sizeof(struct blk_zone) * rep.nr_zones))
ret = -EFAULT;
}
out:
kfree(zones);
return ret;
}
/**
* BLKRESETZONE ioctl processing.
* Called from blkdev_ioctl.
*/
int blkdev_reset_zones_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
struct request_queue *q;
struct blk_zone_range zrange;
if (!argp)
return -EINVAL;
q = bdev_get_queue(bdev);
if (!q)
return -ENXIO;
if (!blk_queue_is_zoned(q))
return -ENOTTY;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (!(mode & FMODE_WRITE))
return -EBADF;
if (copy_from_user(&zrange, argp, sizeof(struct blk_zone_range)))
return -EFAULT;
return blkdev_reset_zones(bdev, zrange.sector, zrange.nr_sectors,
GFP_KERNEL);
}
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