diff --git a/debian/changelog b/debian/changelog index 2f2a5cc5f..9c2c7fac0 100644 --- a/debian/changelog +++ b/debian/changelog @@ -2,6 +2,7 @@ linux (4.14.13-2) UNRELEASED; urgency=medium * RDS: Heap OOB write in rds_message_alloc_sgs() (CVE-2018-5332) * RDS: null pointer dereference in rds_atomic_free_op (CVE-2018-5333) + * loop: fix concurrent lo_open/lo_release (CVE-2018-5344) -- Salvatore Bonaccorso Tue, 16 Jan 2018 20:50:23 +0100 diff --git a/debian/patches/bugfix/all/loop-fix-concurrent-lo_open-lo_release.patch b/debian/patches/bugfix/all/loop-fix-concurrent-lo_open-lo_release.patch new file mode 100644 index 000000000..a5ba39e4b --- /dev/null +++ b/debian/patches/bugfix/all/loop-fix-concurrent-lo_open-lo_release.patch @@ -0,0 +1,56 @@ +From: Linus Torvalds +Date: Fri, 5 Jan 2018 16:26:00 -0800 +Subject: loop: fix concurrent lo_open/lo_release +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +Origin: https://git.kernel.org/linus/ae6650163c66a7eff1acd6eb8b0f752dcfa8eba5 +Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-5344 + +范龙飞 reports that KASAN can report a use-after-free in __lock_acquire. +The reason is due to insufficient serialization in lo_release(), which +will continue to use the loop device even after it has decremented the +lo_refcnt to zero. + +In the meantime, another process can come in, open the loop device +again as it is being shut down. Confusion ensues. + +Reported-by: 范龙飞 +Signed-off-by: Linus Torvalds +Signed-off-by: Jens Axboe +--- + drivers/block/loop.c | 10 ++++++++-- + 1 file changed, 8 insertions(+), 2 deletions(-) + +diff --git a/drivers/block/loop.c b/drivers/block/loop.c +index bc8e61506968..d5fe720cf149 100644 +--- a/drivers/block/loop.c ++++ b/drivers/block/loop.c +@@ -1581,9 +1581,8 @@ static int lo_open(struct block_device *bdev, fmode_t mode) + return err; + } + +-static void lo_release(struct gendisk *disk, fmode_t mode) ++static void __lo_release(struct loop_device *lo) + { +- struct loop_device *lo = disk->private_data; + int err; + + if (atomic_dec_return(&lo->lo_refcnt)) +@@ -1610,6 +1609,13 @@ static void lo_release(struct gendisk *disk, fmode_t mode) + mutex_unlock(&lo->lo_ctl_mutex); + } + ++static void lo_release(struct gendisk *disk, fmode_t mode) ++{ ++ mutex_lock(&loop_index_mutex); ++ __lo_release(disk->private_data); ++ mutex_unlock(&loop_index_mutex); ++} ++ + static const struct block_device_operations lo_fops = { + .owner = THIS_MODULE, + .open = lo_open, +-- +2.15.1 + diff --git a/debian/patches/series b/debian/patches/series index f502e75d5..8e4bcf339 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -133,6 +133,7 @@ bugfix/all/bpf-move-global-verifier-log-into-verifier-environme.patch bugfix/all/bpf-fix-integer-overflows.patch bugfix/all/RDS-Heap-OOB-write-in-rds_message_alloc_sgs.patch bugfix/all/RDS-null-pointer-dereference-in-rds_atomic_free_op.patch +bugfix/all/loop-fix-concurrent-lo_open-lo_release.patch # Fix exported symbol versions bugfix/all/module-disable-matching-missing-version-crc.patch