Sorry, I misspelled the email address of Greg, please omit this email, and I had sent a new one. On 9/18/21 10:26 AM, Jeffle Xu wrote: > From: Ye Bin <yebin10@xxxxxxxxxx> > > Hi Greg, > > Ye Bin had ever fixed a use-after-free of dm-thin in v5.9, and the > complete patchset contains three patches: > > [1/3] d16ff19e69ab dm cache metadata: Avoid returning cmd->bm wild pointer on error > [2/3] 219403d7e56f dm thin metadata: Avoid returning cmd->bm wild pointer on error > [3/3] 3a653b205f29 dm thin metadata: Fix use-after-free in dm_bm_set_read_only > > However, 4.19.y stable only picks the former two patches [1]: > [1/3] 67f03c3d6829 dm cache metadata: Avoid returning cmd->bm wild pointer on error > [2/3] 2c00ee626ed4 dm thin metadata: Avoid returning cmd->bm wild pointer on error > > We encountered a NULL crash and xiejingfeng found that the omitted patch 3 can > fix that. I'm not sure why patch 3 is not picked then, and we need this patch > to fix this issue. > > [32402.449200] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > [32402.459553] Oops: 0002 [#1] SMP NOPTI > [32402.483982] RIP: 0010:dm_bm_set_read_only+0x5/0x10 [dm_persistent_data] > [32402.588073] Call Trace: > [32402.590522] dm_pool_metadata_read_only+0x22/0x30 [dm_thin_pool] > [32402.596526] set_pool_mode+0x209/0x2e0 [dm_thin_pool] > [32402.601579] metadata_operation_failed+0xd5/0xf0 [dm_thin_pool] > [32402.607499] commit+0x91/0xf0 [dm_thin_pool] > [32402.611771] pool_status+0x28a/0x700 [dm_thin_pool] > [32402.616652] retrieve_status+0xa1/0x1c0 [dm_mod] > [32402.627794] table_status+0x61/0xa0 [dm_mod] > [32402.632068] ctl_ioctl+0x1b3/0x480 [dm_mod] > [32402.636253] dm_ctl_ioctl+0xa/0x10 [dm_mod] > [32402.640440] do_vfs_ioctl+0x9f/0x610 > [32402.653081] ksys_ioctl+0x70/0x80 > [32402.656393] __x64_sys_ioctl+0x16/0x20 > [32402.660145] do_syscall_64+0x7b/0x200 > [32402.663813] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > [1] https://lore.kernel.org/lkml/20200908152225.086536876@xxxxxxxxxxxxxxxxxxx/ > > --- > commit 3a653b205f29b3f9827a01a0c88bfbcb0d169494 upstream. > > The following error ocurred when testing disk online/offline: > > [ 301.798344] device-mapper: thin: 253:5: aborting current metadata transaction > [ 301.848441] device-mapper: thin: 253:5: failed to abort metadata transaction > [ 301.849206] Aborting journal on device dm-26-8. > [ 301.850489] EXT4-fs error (device dm-26) in __ext4_new_inode:943: Journal has aborted > [ 301.851095] EXT4-fs (dm-26): Delayed block allocation failed for inode 398742 at logical offset 181 with max blocks 19 with error 30 > [ 301.854476] BUG: KASAN: use-after-free in dm_bm_set_read_only+0x3a/0x40 [dm_persistent_data] > > Reason is: > > metadata_operation_failed > abort_transaction > dm_pool_abort_metadata > __create_persistent_data_objects > r = __open_or_format_metadata > if (r) --> If failed will free pmd->bm but pmd->bm not set NULL > dm_block_manager_destroy(pmd->bm); > set_pool_mode > dm_pool_metadata_read_only(pool->pmd); > dm_bm_set_read_only(pmd->bm); --> use-after-free > > Add checks to see if pmd->bm is NULL in dm_bm_set_read_only and > dm_bm_set_read_write functions. If bm is NULL it means creating the > bm failed and so dm_bm_is_read_only must return true. > > Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> > Signed-off-by: xiejingfeng <xiejingfeng@xxxxxxxxxxxxxxxxx> > Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx> > --- > drivers/md/dm-thin-metadata.c | 2 +- > drivers/md/persistent-data/dm-block-manager.c | 14 ++++++++------ > 2 files changed, 9 insertions(+), 7 deletions(-) > > diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c > index 85077f4d257a..a6a5cee6b943 100644 > --- a/drivers/md/dm-thin-metadata.c > +++ b/drivers/md/dm-thin-metadata.c > @@ -901,7 +901,7 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd) > return -EBUSY; > } > > - if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) { > + if (!pmd->fail_io && !dm_bm_is_read_only(pmd->bm)) { > r = __commit_transaction(pmd); > if (r < 0) > DMWARN("%s: __commit_transaction() failed, error = %d", > diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c > index 492a3f8ac119..0401daa0f7fb 100644 > --- a/drivers/md/persistent-data/dm-block-manager.c > +++ b/drivers/md/persistent-data/dm-block-manager.c > @@ -494,7 +494,7 @@ int dm_bm_write_lock(struct dm_block_manager *bm, > void *p; > int r; > > - if (bm->read_only) > + if (dm_bm_is_read_only(bm)) > return -EPERM; > > p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result); > @@ -563,7 +563,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm, > struct buffer_aux *aux; > void *p; > > - if (bm->read_only) > + if (dm_bm_is_read_only(bm)) > return -EPERM; > > p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result); > @@ -603,7 +603,7 @@ EXPORT_SYMBOL_GPL(dm_bm_unlock); > > int dm_bm_flush(struct dm_block_manager *bm) > { > - if (bm->read_only) > + if (dm_bm_is_read_only(bm)) > return -EPERM; > > return dm_bufio_write_dirty_buffers(bm->bufio); > @@ -617,19 +617,21 @@ void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b) > > bool dm_bm_is_read_only(struct dm_block_manager *bm) > { > - return bm->read_only; > + return (bm ? bm->read_only : true); > } > EXPORT_SYMBOL_GPL(dm_bm_is_read_only); > > void dm_bm_set_read_only(struct dm_block_manager *bm) > { > - bm->read_only = true; > + if (bm) > + bm->read_only = true; > } > EXPORT_SYMBOL_GPL(dm_bm_set_read_only); > > void dm_bm_set_read_write(struct dm_block_manager *bm) > { > - bm->read_only = false; > + if (bm) > + bm->read_only = false; > } > EXPORT_SYMBOL_GPL(dm_bm_set_read_write); > > -- Thanks, Jeffle
