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md: avoid invalid memory access for array sb->dev_roles 

we need to gurantee 'desc_nr' valid before access array
of sb->dev_roles.

In addition, we should avoid .load_super always return '0'
when level is LEVEL_MULTIPATH, which is not expected.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1487373 ("Memory - illegal accesses")
Fixes: 6a5cb53aaa ("md: no longer compare spare disk superblock events in super_load")
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
alistair/sunxi64-5.5-dsi
Yufen Yu 2019-10-30 18:47:02 +08:00 committed by Song Liu
parent 5fa4f8bac9
commit 228fc7d76d
1 changed files with 20 additions and 31 deletions
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51
drivers/md/md.c
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@ -1105,6 +1105,7 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
mdp_super_t *sb;
int ret;
bool spare_disk = true;
/*
* Calculate the position of the superblock (512byte sectors),
@ -1155,13 +1156,15 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
else
rdev->desc_nr = sb->this_disk.number;
/* not spare disk, or LEVEL_MULTIPATH */
if (sb->level == LEVEL_MULTIPATH ||
(rdev->desc_nr >= 0 &&
sb->disks[rdev->desc_nr].state &
((1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE))))
spare_disk = false;
if (!refdev) {
/*
* Insist on good event counter while assembling, except
* for spares (which don't need an event count)
*/
if (sb->disks[rdev->desc_nr].state & (
(1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE)))
if (!spare_disk)
ret = 1;
else
ret = 0;
@ -1181,13 +1184,7 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
ev1 = md_event(sb);
ev2 = md_event(refsb);
/*
* Insist on good event counter while assembling, except
* for spares (which don't need an event count)
*/
if (sb->disks[rdev->desc_nr].state & (
(1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE)) &&
(ev1 > ev2))
if (!spare_disk && ev1 > ev2)
ret = 1;
else
ret = 0;
@ -1547,7 +1544,7 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
sector_t sectors;
char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
int bmask;
__u64 role;
bool spare_disk = true;
/*
* Calculate the position of the superblock in 512byte sectors.
@ -1681,17 +1678,16 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
sb->level != 0)
return -EINVAL;
role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
/* not spare disk, or LEVEL_MULTIPATH */
if (sb->level == cpu_to_le32(LEVEL_MULTIPATH) ||
(rdev->desc_nr >= 0 &&
rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
(le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < MD_DISK_ROLE_MAX ||
le16_to_cpu(sb->dev_roles[rdev->desc_nr]) == MD_DISK_ROLE_JOURNAL)))
spare_disk = false;
if (!refdev) {
/*
* Insist of good event counter while assembling, except for
* spares (which don't need an event count)
*/
if (rdev->desc_nr >= 0 &&
rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
(role < MD_DISK_ROLE_MAX ||
role == MD_DISK_ROLE_JOURNAL))
if (!spare_disk)
ret = 1;
else
ret = 0;
@ -1711,14 +1707,7 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
ev1 = le64_to_cpu(sb->events);
ev2 = le64_to_cpu(refsb->events);
/*
* Insist of good event counter while assembling, except for
* spares (which don't need an event count)
*/
if (rdev->desc_nr >= 0 &&
rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
(role < MD_DISK_ROLE_MAX ||
role == MD_DISK_ROLE_JOURNAL) && ev1 > ev2)
if (!spare_disk && ev1 > ev2)
ret = 1;
else
ret = 0;