v5.11 changes the blkdev lookup mechanism completely since commit
22ae8ce8b892 ("block: simplify bdev/disk lookup in blkdev_get"),
and small part of the change is to unhash part bdev inode when
deleting partition. Turns out this kind of change does fix one
nasty issue in case of BLOCK_EXT_MAJOR:
1) when one partition is deleted & closed, disk_put_part() is always
called before bdput(bdev), see blkdev_put(); so the part's devt can
be freed & re-used before the inode is dropped
2) then new partition with same devt can be created just before the
inode in 1) is dropped, then the old inode/bdev structurein 1) is
re-used for this new partition, this way causes use-after-free and
kernel panic.
It isn't possible to backport the whole big patchset of "merge struct
block_device and struct hd_struct v4" for addressing this issue.
https://lore.kernel.org/linux-block/20201128161510.347752-1-hch@lst.de/
So fixes it by unhashing part bdev in delete_partition(), and this way
is actually aligned with v5.11+'s behavior.
Backported from the following 5.10.y commit:
5f2f77560591 ("block: unhash blkdev part inode when the part is deleted")
Reported-by: Shiwei Cui <cuishw(a)inspur.com>
Tested-by: Shiwei Cui <cuishw(a)inspur.com>
Cc: Christoph Hellwig <hch(a)lst.de>
Cc: Jan Kara <jack(a)suse.cz>
Signed-off-by: Ming Lei <ming.lei(a)redhat.com>
---
block/partition-generic.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/block/partition-generic.c b/block/partition-generic.c
index 298c05f8b5e3..434c122cb958 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -254,6 +254,7 @@ void delete_partition(struct gendisk *disk, int partno)
{
struct disk_part_tbl *ptbl = disk->part_tbl;
struct hd_struct *part;
+ struct block_device *bdev;
if (partno >= ptbl->len)
return;
@@ -267,6 +268,11 @@ void delete_partition(struct gendisk *disk, int partno)
kobject_put(part->holder_dir);
device_del(part_to_dev(part));
+ bdev = bdget(part_devt(part));
+ if (bdev) {
+ remove_inode_hash(bdev->bd_inode);
+ bdput(bdev);
+ }
hd_struct_kill(part);
}
--
2.38.1
A bad bug in clang's implementation of -fzero-call-used-regs can result
in NULL pointer dereferences (see the links above the check for more
information). Restrict CONFIG_CC_HAS_ZERO_CALL_USED_REGS to either a
supported GCC version or a clang newer than 15.0.6, which will catch
both a theoretical 15.0.7 and the upcoming 16.0.0, which will both have
the bug fixed.
Cc: stable(a)vger.kernel.org # v5.15+
Signed-off-by: Nathan Chancellor <nathan(a)kernel.org>
---
security/Kconfig.hardening | 3 +++
1 file changed, 3 insertions(+)
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index d766b7d0ffd1..53baa95cb644 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -257,6 +257,9 @@ config INIT_ON_FREE_DEFAULT_ON
config CC_HAS_ZERO_CALL_USED_REGS
def_bool $(cc-option,-fzero-call-used-regs=used-gpr)
+ # https://github.com/ClangBuiltLinux/linux/issues/1766
+ # https://github.com/llvm/llvm-project/issues/59242
+ depends on !CC_IS_CLANG || CLANG_VERSION > 150006
config ZERO_CALL_USED_REGS
bool "Enable register zeroing on function exit"
base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476
--
2.39.0