diff options
Diffstat (limited to 'meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2020-15436/0001-block-Fix-use-after-free-in-blkdev_get.patch')
| -rw-r--r-- | meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2020-15436/0001-block-Fix-use-after-free-in-blkdev_get.patch | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2020-15436/0001-block-Fix-use-after-free-in-blkdev_get.patch b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2020-15436/0001-block-Fix-use-after-free-in-blkdev_get.patch new file mode 100644 index 000000000..958fb1967 --- /dev/null +++ b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2020-15436/0001-block-Fix-use-after-free-in-blkdev_get.patch @@ -0,0 +1,194 @@ +From 2d3a8e2deddea6c89961c422ec0c5b851e648c14 Mon Sep 17 00:00:00 2001 +From: Jason Yan <yanaijie@huawei.com> +Date: Tue, 16 Jun 2020 20:16:55 +0800 +Subject: [PATCH] block: Fix use-after-free in blkdev_get() + +In blkdev_get() we call __blkdev_get() to do some internal jobs and if +there is some errors in __blkdev_get(), the bdput() is called which +means we have released the refcount of the bdev (actually the refcount of +the bdev inode). This means we cannot access bdev after that point. But +acctually bdev is still accessed in blkdev_get() after calling +__blkdev_get(). This results in use-after-free if the refcount is the +last one we released in __blkdev_get(). Let's take a look at the +following scenerio: + + CPU0 CPU1 CPU2 +blkdev_open blkdev_open Remove disk + bd_acquire + blkdev_get + __blkdev_get del_gendisk + bdev_unhash_inode + bd_acquire bdev_get_gendisk + bd_forget failed because of unhashed + bdput + bdput (the last one) + bdev_evict_inode + + access bdev => use after free + +[ 459.350216] BUG: KASAN: use-after-free in __lock_acquire+0x24c1/0x31b0 +[ 459.351190] Read of size 8 at addr ffff88806c815a80 by task syz-executor.0/20132 +[ 459.352347] +[ 459.352594] CPU: 0 PID: 20132 Comm: syz-executor.0 Not tainted 4.19.90 #2 +[ 459.353628] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 +[ 459.354947] Call Trace: +[ 459.355337] dump_stack+0x111/0x19e +[ 459.355879] ? __lock_acquire+0x24c1/0x31b0 +[ 459.356523] print_address_description+0x60/0x223 +[ 459.357248] ? __lock_acquire+0x24c1/0x31b0 +[ 459.357887] kasan_report.cold+0xae/0x2d8 +[ 459.358503] __lock_acquire+0x24c1/0x31b0 +[ 459.359120] ? _raw_spin_unlock_irq+0x24/0x40 +[ 459.359784] ? lockdep_hardirqs_on+0x37b/0x580 +[ 459.360465] ? _raw_spin_unlock_irq+0x24/0x40 +[ 459.361123] ? finish_task_switch+0x125/0x600 +[ 459.361812] ? finish_task_switch+0xee/0x600 +[ 459.362471] ? mark_held_locks+0xf0/0xf0 +[ 459.363108] ? __schedule+0x96f/0x21d0 +[ 459.363716] lock_acquire+0x111/0x320 +[ 459.364285] ? blkdev_get+0xce/0xbe0 +[ 459.364846] ? blkdev_get+0xce/0xbe0 +[ 459.365390] __mutex_lock+0xf9/0x12a0 +[ 459.365948] ? blkdev_get+0xce/0xbe0 +[ 459.366493] ? bdev_evict_inode+0x1f0/0x1f0 +[ 459.367130] ? blkdev_get+0xce/0xbe0 +[ 459.367678] ? destroy_inode+0xbc/0x110 +[ 459.368261] ? mutex_trylock+0x1a0/0x1a0 +[ 459.368867] ? __blkdev_get+0x3e6/0x1280 +[ 459.369463] ? bdev_disk_changed+0x1d0/0x1d0 +[ 459.370114] ? blkdev_get+0xce/0xbe0 +[ 459.370656] blkdev_get+0xce/0xbe0 +[ 459.371178] ? find_held_lock+0x2c/0x110 +[ 459.371774] ? __blkdev_get+0x1280/0x1280 +[ 459.372383] ? lock_downgrade+0x680/0x680 +[ 459.373002] ? lock_acquire+0x111/0x320 +[ 459.373587] ? bd_acquire+0x21/0x2c0 +[ 459.374134] ? do_raw_spin_unlock+0x4f/0x250 +[ 459.374780] blkdev_open+0x202/0x290 +[ 459.375325] do_dentry_open+0x49e/0x1050 +[ 459.375924] ? blkdev_get_by_dev+0x70/0x70 +[ 459.376543] ? __x64_sys_fchdir+0x1f0/0x1f0 +[ 459.377192] ? inode_permission+0xbe/0x3a0 +[ 459.377818] path_openat+0x148c/0x3f50 +[ 459.378392] ? kmem_cache_alloc+0xd5/0x280 +[ 459.379016] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe +[ 459.379802] ? path_lookupat.isra.0+0x900/0x900 +[ 459.380489] ? __lock_is_held+0xad/0x140 +[ 459.381093] do_filp_open+0x1a1/0x280 +[ 459.381654] ? may_open_dev+0xf0/0xf0 +[ 459.382214] ? find_held_lock+0x2c/0x110 +[ 459.382816] ? lock_downgrade+0x680/0x680 +[ 459.383425] ? __lock_is_held+0xad/0x140 +[ 459.384024] ? do_raw_spin_unlock+0x4f/0x250 +[ 459.384668] ? _raw_spin_unlock+0x1f/0x30 +[ 459.385280] ? __alloc_fd+0x448/0x560 +[ 459.385841] do_sys_open+0x3c3/0x500 +[ 459.386386] ? filp_open+0x70/0x70 +[ 459.386911] ? trace_hardirqs_on_thunk+0x1a/0x1c +[ 459.387610] ? trace_hardirqs_off_caller+0x55/0x1c0 +[ 459.388342] ? do_syscall_64+0x1a/0x520 +[ 459.388930] do_syscall_64+0xc3/0x520 +[ 459.389490] entry_SYSCALL_64_after_hwframe+0x49/0xbe +[ 459.390248] RIP: 0033:0x416211 +[ 459.390720] Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 +04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff 48 89 04 24 b8 02 00 00 00 0f + 05 <48> 8b 3c 24 48 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d + 01 +[ 459.393483] RSP: 002b:00007fe45dfe9a60 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 +[ 459.394610] RAX: ffffffffffffffda RBX: 00007fe45dfea6d4 RCX: 0000000000416211 +[ 459.395678] RDX: 00007fe45dfe9b0a RSI: 0000000000000002 RDI: 00007fe45dfe9b00 +[ 459.396758] RBP: 000000000076bf20 R08: 0000000000000000 R09: 000000000000000a +[ 459.397930] R10: 0000000000000075 R11: 0000000000000293 R12: 00000000ffffffff +[ 459.399022] R13: 0000000000000bd9 R14: 00000000004cdb80 R15: 000000000076bf2c +[ 459.400168] +[ 459.400430] Allocated by task 20132: +[ 459.401038] kasan_kmalloc+0xbf/0xe0 +[ 459.401652] kmem_cache_alloc+0xd5/0x280 +[ 459.402330] bdev_alloc_inode+0x18/0x40 +[ 459.402970] alloc_inode+0x5f/0x180 +[ 459.403510] iget5_locked+0x57/0xd0 +[ 459.404095] bdget+0x94/0x4e0 +[ 459.404607] bd_acquire+0xfa/0x2c0 +[ 459.405113] blkdev_open+0x110/0x290 +[ 459.405702] do_dentry_open+0x49e/0x1050 +[ 459.406340] path_openat+0x148c/0x3f50 +[ 459.406926] do_filp_open+0x1a1/0x280 +[ 459.407471] do_sys_open+0x3c3/0x500 +[ 459.408010] do_syscall_64+0xc3/0x520 +[ 459.408572] entry_SYSCALL_64_after_hwframe+0x49/0xbe +[ 459.409415] +[ 459.409679] Freed by task 1262: +[ 459.410212] __kasan_slab_free+0x129/0x170 +[ 459.410919] kmem_cache_free+0xb2/0x2a0 +[ 459.411564] rcu_process_callbacks+0xbb2/0x2320 +[ 459.412318] __do_softirq+0x225/0x8ac + +Fix this by delaying bdput() to the end of blkdev_get() which means we +have finished accessing bdev. + +Fixes: 77ea887e433a ("implement in-kernel gendisk events handling") +Reported-by: Hulk Robot <hulkci@huawei.com> +Signed-off-by: Jason Yan <yanaijie@huawei.com> +Tested-by: Sedat Dilek <sedat.dilek@gmail.com> +Reviewed-by: Jan Kara <jack@suse.cz> +Reviewed-by: Christoph Hellwig <hch@lst.de> +Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> +Cc: Christoph Hellwig <hch@lst.de> +Cc: Jens Axboe <axboe@kernel.dk> +Cc: Ming Lei <ming.lei@redhat.com> +Cc: Jan Kara <jack@suse.cz> +Cc: Dan Carpenter <dan.carpenter@oracle.com> +Signed-off-by: Jens Axboe <axboe@kernel.dk> +--- + fs/block_dev.c | 12 +++++++----- + 1 file changed, 7 insertions(+), 5 deletions(-) + +diff --git a/fs/block_dev.c b/fs/block_dev.c +index 47860e589388..08c87db3a92b 100644 +--- a/fs/block_dev.c ++++ b/fs/block_dev.c +@@ -1565,10 +1565,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) + */ + if (!for_part) { + ret = devcgroup_inode_permission(bdev->bd_inode, perm); +- if (ret != 0) { +- bdput(bdev); ++ if (ret != 0) + return ret; +- } + } + + restart: +@@ -1637,8 +1635,10 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) + goto out_clear; + BUG_ON(for_part); + ret = __blkdev_get(whole, mode, 1); +- if (ret) ++ if (ret) { ++ bdput(whole); + goto out_clear; ++ } + bdev->bd_contains = whole; + bdev->bd_part = disk_get_part(disk, partno); + if (!(disk->flags & GENHD_FL_UP) || +@@ -1688,7 +1688,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) + disk_unblock_events(disk); + put_disk_and_module(disk); + out: +- bdput(bdev); + + return ret; + } +@@ -1755,6 +1754,9 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) + bdput(whole); + } + ++ if (res) ++ bdput(bdev); ++ + return res; + } + EXPORT_SYMBOL(blkdev_get); +-- +2.17.1 + |