From 2d06dfecb132a1cc2e374a44eae83b5c4356b8b4 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Wed, 20 Jan 2021 06:02:31 -0500
Subject: [PATCH 1/4] dm integrity: fix a crash if "recalculate" used without
"internal_hash"
Recalculate can only be specified with internal_hash.
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm-integrity.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 81df019ab284..cce203adcf77 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -4235,6 +4235,12 @@ try_smaller_buffer:
r = -ENOMEM;
goto bad;
}
+ } else {
+ if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING)) {
+ ti->error = "Recalculate can only be specified with internal_hash";
+ r = -EINVAL;
+ goto bad;
+ }
}
ic->bufio = dm_bufio_client_create(ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev,
From 5c02406428d5219c367c5f53457698c58bc5f917 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Wed, 20 Jan 2021 13:59:11 -0500
Subject: [PATCH 2/4] dm integrity: conditionally disable "recalculate" feature
Otherwise a malicious user could (ab)use the "recalculate" feature
that makes dm-integrity calculate the checksums in the background
while the device is already usable. When the system restarts before all
checksums have been calculated, the calculation continues where it was
interrupted even if the recalculate feature is not requested the next
time the dm device is set up.
Disable recalculating if we use internal_hash or journal_hash with a
key (e.g. HMAC) and we don't have the "legacy_recalculate" flag.
This may break activation of a volume, created by an older kernel,
that is not yet fully recalculated -- if this happens, the user should
add the "legacy_recalculate" flag to constructor parameters.
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Daniel Glockner <dg@emlix.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
.../device-mapper/dm-integrity.rst | 12 ++++++---
drivers/md/dm-integrity.c | 26 +++++++++++++++++--
2 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/device-mapper/dm-integrity.rst b/Documentation/admin-guide/device-mapper/dm-integrity.rst
index 4e6f504474ac..2cc5488acbd9 100644
--- a/Documentation/admin-guide/device-mapper/dm-integrity.rst
+++ b/Documentation/admin-guide/device-mapper/dm-integrity.rst
@@ -177,14 +177,20 @@ bitmap_flush_interval:number
The bitmap flush interval in milliseconds. The metadata buffers
are synchronized when this interval expires.
+allow_discards
+ Allow block discard requests (a.k.a. TRIM) for the integrity device.
+ Discards are only allowed to devices using internal hash.
+
fix_padding
Use a smaller padding of the tag area that is more
space-efficient. If this option is not present, large padding is
used - that is for compatibility with older kernels.
-allow_discards
- Allow block discard requests (a.k.a. TRIM) for the integrity device.
- Discards are only allowed to devices using internal hash.
+legacy_recalculate
+ Allow recalculating of volumes with HMAC keys. This is disabled by
+ default for security reasons - an attacker could modify the volume,
+ set recalc_sector to zero, and the kernel would not detect the
+ modification.
The journal mode (D/J), buffer_sectors, journal_watermark, commit_time and
allow_discards can be changed when reloading the target (load an inactive
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index cce203adcf77..b64fede032dc 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -257,8 +257,9 @@ struct dm_integrity_c {
bool journal_uptodate;
bool just_formatted;
bool recalculate_flag;
- bool fix_padding;
bool discard;
+ bool fix_padding;
+ bool legacy_recalculate;
struct alg_spec internal_hash_alg;
struct alg_spec journal_crypt_alg;
@@ -386,6 +387,14 @@ static int dm_integrity_failed(struct dm_integrity_c *ic)
return READ_ONCE(ic->failed);
}
+static bool dm_integrity_disable_recalculate(struct dm_integrity_c *ic)
+{
+ if ((ic->internal_hash_alg.key || ic->journal_mac_alg.key) &&
+ !ic->legacy_recalculate)
+ return true;
+ return false;
+}
+
static commit_id_t dm_integrity_commit_id(struct dm_integrity_c *ic, unsigned i,
unsigned j, unsigned char seq)
{
@@ -3140,6 +3149,7 @@ static void dm_integrity_status(struct dm_target *ti, status_type_t type,
arg_count += !!ic->journal_crypt_alg.alg_string;
arg_count += !!ic->journal_mac_alg.alg_string;
arg_count += (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_PADDING)) != 0;
+ arg_count += ic->legacy_recalculate;
DMEMIT("%s %llu %u %c %u", ic->dev->name, ic->start,
ic->tag_size, ic->mode, arg_count);
if (ic->meta_dev)
@@ -3163,6 +3173,8 @@ static void dm_integrity_status(struct dm_target *ti, status_type_t type,
}
if ((ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_PADDING)) != 0)
DMEMIT(" fix_padding");
+ if (ic->legacy_recalculate)
+ DMEMIT(" legacy_recalculate");
#define EMIT_ALG(a, n) \
do { \
@@ -3792,7 +3804,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
unsigned extra_args;
struct dm_arg_set as;
static const struct dm_arg _args[] = {
- {0, 15, "Invalid number of feature args"},
+ {0, 16, "Invalid number of feature args"},
};
unsigned journal_sectors, interleave_sectors, buffer_sectors, journal_watermark, sync_msec;
bool should_write_sb;
@@ -3940,6 +3952,8 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
ic->discard = true;
} else if (!strcmp(opt_string, "fix_padding")) {
ic->fix_padding = true;
+ } else if (!strcmp(opt_string, "legacy_recalculate")) {
+ ic->legacy_recalculate = true;
} else {
r = -EINVAL;
ti->error = "Invalid argument";
@@ -4243,6 +4257,14 @@ try_smaller_buffer:
}
}
+ if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING) &&
+ le64_to_cpu(ic->sb->recalc_sector) < ic->provided_data_sectors &&
+ dm_integrity_disable_recalculate(ic)) {
+ ti->error = "Recalculating with HMAC is disabled for security reasons - if you really need it, use the argument \"legacy_recalculate\"";
+ r = -EOPNOTSUPP;
+ goto bad;
+ }
+
ic->bufio = dm_bufio_client_create(ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev,
1U << (SECTOR_SHIFT + ic->log2_buffer_sectors), 1, 0, NULL, NULL);
if (IS_ERR(ic->bufio)) {
From 004b8ae9e2de55ca7857ba8471209dd3179e088c Mon Sep 17 00:00:00 2001
From: Ignat Korchagin <ignat@cloudflare.com>
Date: Tue, 19 Jan 2021 20:40:15 +0000
Subject: [PATCH 3/4] dm crypt: fix copy and paste bug in crypt_alloc_req_aead
In commit d68b29584c25 ("dm crypt: use GFP_ATOMIC when allocating
crypto requests from softirq") code was incorrectly copy and pasted
from crypt_alloc_req_skcipher()'s crypto request allocation code to
crypt_alloc_req_aead(). It is OK from runtime perspective as both
simple encryption request pointer and AEAD request pointer are part of
a union, but may confuse code reviewers.
Fixes: d68b29584c25 ("dm crypt: use GFP_ATOMIC when allocating crypto requests from softirq")
Cc: stable@vger.kernel.org # v5.9+
Reported-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm-crypt.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 8c874710f0bc..5a55617a08e6 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1481,9 +1481,9 @@ static int crypt_alloc_req_skcipher(struct crypt_config *cc,
static int crypt_alloc_req_aead(struct crypt_config *cc,
struct convert_context *ctx)
{
- if (!ctx->r.req) {
- ctx->r.req = mempool_alloc(&cc->req_pool, in_interrupt() ? GFP_ATOMIC : GFP_NOIO);
- if (!ctx->r.req)
+ if (!ctx->r.req_aead) {
+ ctx->r.req_aead = mempool_alloc(&cc->req_pool, in_interrupt() ? GFP_ATOMIC : GFP_NOIO);
+ if (!ctx->r.req_aead)
return -ENOMEM;
}
From 809b1e4945774c9ec5619a8f4e2189b7b3833c0c Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@suse.de>
Date: Thu, 21 Jan 2021 18:50:56 +0100
Subject: [PATCH 4/4] dm: avoid filesystem lookup in dm_get_dev_t()
This reverts commit
644bda6f3460 ("dm table: fall back to getting device using name_to_dev_t()")
dm_get_dev_t() is just used to convert an arbitrary 'path' string
into a dev_t. It doesn't presume that the device is present; that
check will be done later, as the only caller is dm_get_device(),
which does a dm_get_table_device() later on, which will properly
open the device.
So if the path string already _is_ in major:minor representation
we can convert it directly, avoiding a recursion into the filesystem
to lookup the block device.
This avoids a hang in multipath_message() when the filesystem is
inaccessible.
Fixes: 644bda6f3460 ("dm table: fall back to getting device using name_to_dev_t()")
Cc: stable@vger.kernel.org
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm-table.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 188f41287f18..4acf2342f7ad 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -363,14 +363,23 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
{
int r;
dev_t dev;
+ unsigned int major, minor;
+ char dummy;
struct dm_dev_internal *dd;
struct dm_table *t = ti->table;
BUG_ON(!t);
- dev = dm_get_dev_t(path);
- if (!dev)
- return -ENODEV;
+ if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
+ /* Extract the major/minor numbers */
+ dev = MKDEV(major, minor);
+ if (MAJOR(dev) != major || MINOR(dev) != minor)
+ return -EOVERFLOW;
+ } else {
+ dev = dm_get_dev_t(path);
+ if (!dev)
+ return -ENODEV;
+ }
dd = find_device(&t->devices, dev);
if (!dd) {