From f1a880a93baaadb14c10a348fd199f1cdb6bcccd Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Wed, 15 Mar 2017 15:12:23 -0700 Subject: dm verity fec: limit error correction recursion If the hash tree itself is sufficiently corrupt in addition to data blocks, it's possible for error correction to end up in a deep recursive loop, which eventually causes a kernel panic. This change limits the recursion to a reasonable level during a single I/O operation. Fixes: a739ff3f543a ("dm verity: add support for forward error correction") Signed-off-by: Sami Tolvanen Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org # v4.5+ --- drivers/md/dm-verity-fec.c | 12 +++++++++++- drivers/md/dm-verity-fec.h | 4 ++++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c index 0f0eb8a3d922..c3cc04d89524 100644 --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -439,6 +439,13 @@ int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, if (!verity_fec_is_enabled(v)) return -EOPNOTSUPP; + if (fio->level >= DM_VERITY_FEC_MAX_RECURSION) { + DMWARN_LIMIT("%s: FEC: recursion too deep", v->data_dev->name); + return -EIO; + } + + fio->level++; + if (type == DM_VERITY_BLOCK_TYPE_METADATA) block += v->data_blocks; @@ -470,7 +477,7 @@ int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, if (r < 0) { r = fec_decode_rsb(v, io, fio, rsb, offset, true); if (r < 0) - return r; + goto done; } if (dest) @@ -480,6 +487,8 @@ int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, r = verity_for_bv_block(v, io, iter, fec_bv_copy); } +done: + fio->level--; return r; } @@ -520,6 +529,7 @@ void verity_fec_init_io(struct dm_verity_io *io) memset(fio->bufs, 0, sizeof(fio->bufs)); fio->nbufs = 0; fio->output = NULL; + fio->level = 0; } /* diff --git a/drivers/md/dm-verity-fec.h b/drivers/md/dm-verity-fec.h index 7fa0298b995e..bb31ce87a933 100644 --- a/drivers/md/dm-verity-fec.h +++ b/drivers/md/dm-verity-fec.h @@ -27,6 +27,9 @@ #define DM_VERITY_FEC_BUF_MAX \ (1 << (PAGE_SHIFT - DM_VERITY_FEC_BUF_RS_BITS)) +/* maximum recursion level for verity_fec_decode */ +#define DM_VERITY_FEC_MAX_RECURSION 4 + #define DM_VERITY_OPT_FEC_DEV "use_fec_from_device" #define DM_VERITY_OPT_FEC_BLOCKS "fec_blocks" #define DM_VERITY_OPT_FEC_START "fec_start" @@ -58,6 +61,7 @@ struct dm_verity_fec_io { unsigned nbufs; /* number of buffers allocated */ u8 *output; /* buffer for corrected output */ size_t output_pos; + unsigned level; /* recursion level */ }; #ifdef CONFIG_DM_VERITY_FEC -- cgit v1.2.3-70-g09d2 From 0d963b6e650d9d5533223f3dbcde7dda466df65c Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Mon, 20 Mar 2017 11:54:11 -0400 Subject: dm cache metadata: fix metadata2 format's blocks_are_clean_separate_dirty The dm_bitset_cursor_begin() call was using the incorrect nr_entries. Also, the last dm_bitset_cursor_next() must be avoided if we're at the end of the cursor. Fixes: 7f1b21591a6 ("dm cache metadata: use cursor api in blocks_are_clean_separate_dirty()") Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- drivers/md/dm-cache-metadata.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index e4c2c1a1e993..6735c8d6a445 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -932,7 +932,7 @@ static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, *result = true; r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, - from_cblock(begin), &cmd->dirty_cursor); + from_cblock(cmd->cache_blocks), &cmd->dirty_cursor); if (r) { DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__); return r; @@ -959,14 +959,16 @@ static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, return 0; } + begin = to_cblock(from_cblock(begin) + 1); + if (begin == end) + break; + r = dm_bitset_cursor_next(&cmd->dirty_cursor); if (r) { DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__); dm_bitset_cursor_end(&cmd->dirty_cursor); return r; } - - begin = to_cblock(from_cblock(begin) + 1); } dm_bitset_cursor_end(&cmd->dirty_cursor); -- cgit v1.2.3-70-g09d2 From 7a0c5c5b834fb60764b494b0e39c239da3b0774b Mon Sep 17 00:00:00 2001 From: Dmitry Bilunov Date: Thu, 30 Mar 2017 18:14:26 +0300 Subject: dm raid: fix NULL pointer dereference for raid1 without bitmap MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 4257e08 ("dm raid: support to change bitmap region size") introduced a bitmap resize call during preresume phase. User can create a DM device with "raid" target configured as raid1 with no metadata devices to hold superblock/bitmap info. It can be achieved using the following sequence: truncate -s 32M /dev/shm/raid-test LOOP=$(losetup --show -f /dev/shm/raid-test) dmsetup create raid-test-linear0 --table "0 1024 linear $LOOP 0" dmsetup create raid-test-linear1 --table "0 1024 linear $LOOP 1024" dmsetup create raid-test --table "0 1024 raid raid1 1 2048 2 - /dev/mapper/raid-test-linear0 - /dev/mapper/raid-test-linear1" This results in the following crash: [ 4029.110216] device-mapper: raid: Ignoring chunk size parameter for RAID 1 [ 4029.110217] device-mapper: raid: Choosing default region size of 4MiB [ 4029.111349] md/raid1:mdX: active with 2 out of 2 mirrors [ 4029.114770] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 [ 4029.114802] IP: bitmap_resize+0x25/0x7c0 [md_mod] [ 4029.114816] PGD 0 … [ 4029.115059] Hardware name: Aquarius Pro P30 S85 BUY-866/B85M-E, BIOS 2304 05/25/2015 [ 4029.115079] task: ffff88015cc29a80 task.stack: ffffc90001a5c000 [ 4029.115097] RIP: 0010:bitmap_resize+0x25/0x7c0 [md_mod] [ 4029.115112] RSP: 0018:ffffc90001a5fb68 EFLAGS: 00010246 [ 4029.115127] RAX: 0000000000000005 RBX: 0000000000000000 RCX: 0000000000000000 [ 4029.115146] RDX: 0000000000000000 RSI: 0000000000000400 RDI: 0000000000000000 [ 4029.115166] RBP: ffffc90001a5fc28 R08: 0000000800000000 R09: 00000008ffffffff [ 4029.115185] R10: ffffea0005661600 R11: ffff88015cc29a80 R12: ffff88021231f058 [ 4029.115204] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 4029.115223] FS: 00007fe73a6b4740(0000) GS:ffff88021ea80000(0000) knlGS:0000000000000000 [ 4029.115245] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4029.115261] CR2: 0000000000000030 CR3: 0000000159a74000 CR4: 00000000001426e0 [ 4029.115281] Call Trace: [ 4029.115291] ? raid_iterate_devices+0x63/0x80 [dm_raid] [ 4029.115309] ? dm_table_all_devices_attribute.isra.23+0x41/0x70 [dm_mod] [ 4029.115329] ? dm_table_set_restrictions+0x225/0x2d0 [dm_mod] [ 4029.115346] raid_preresume+0x81/0x2e0 [dm_raid] [ 4029.115361] dm_table_resume_targets+0x47/0xe0 [dm_mod] [ 4029.115378] dm_resume+0xa8/0xd0 [dm_mod] [ 4029.115391] dev_suspend+0x123/0x250 [dm_mod] [ 4029.115405] ? table_load+0x350/0x350 [dm_mod] [ 4029.115419] ctl_ioctl+0x1c2/0x490 [dm_mod] [ 4029.115433] dm_ctl_ioctl+0xe/0x20 [dm_mod] [ 4029.115447] do_vfs_ioctl+0x8d/0x5a0 [ 4029.115459] ? ____fput+0x9/0x10 [ 4029.115470] ? task_work_run+0x79/0xa0 [ 4029.115481] SyS_ioctl+0x3c/0x70 [ 4029.115493] entry_SYSCALL_64_fastpath+0x13/0x94 The raid_preresume() function incorrectly assumes that the raid_set has a bitmap enabled if RT_FLAG_RS_BITMAP_LOADED is set. But RT_FLAG_RS_BITMAP_LOADED is getting set in __load_dirty_region_bitmap() even if there is no bitmap present (and bitmap_load() happily returns 0 even if a bitmap isn't present). So the only way forward in the near-term is to check if the bitmap is present by seeing if mddev->bitmap is not NULL after bitmap_load() has been called. By doing so the above NULL pointer is avoided. Fixes: 4257e08 ("dm raid: support to change bitmap region size") Cc: stable@vger.kernel.org # v4.8+ Signed-off-by: Dmitry Bilunov Signed-off-by: Andrey Smetanin Acked-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer --- drivers/md/dm-raid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index f8564d63982f..1e217ba84d09 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -3726,7 +3726,7 @@ static int raid_preresume(struct dm_target *ti) return r; /* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) */ - if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && + if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap && mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)) { r = bitmap_resize(mddev->bitmap, mddev->dev_sectors, to_bytes(rs->requested_bitmap_chunk_sectors), 0); -- cgit v1.2.3-70-g09d2 From 86e3e83b443669dd2bcc5c8a83b23e3aa0694c0d Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Fri, 31 Mar 2017 12:32:45 -0700 Subject: dm verity fec: fix bufio leaks Buffers read through dm_bufio_read() were not released in all code paths. Fixes: a739ff3f543a ("dm verity: add support for forward error correction") Cc: stable@vger.kernel.org # v4.5+ Signed-off-by: Sami Tolvanen Signed-off-by: Mike Snitzer --- drivers/md/dm-verity-fec.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c index c3cc04d89524..78f36012eaca 100644 --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -146,8 +146,6 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio, block = fec_buffer_rs_block(v, fio, n, i); res = fec_decode_rs8(v, fio, block, &par[offset], neras); if (res < 0) { - dm_bufio_release(buf); - r = res; goto error; } @@ -172,6 +170,8 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio, done: r = corrected; error: + dm_bufio_release(buf); + if (r < 0 && neras) DMERR_LIMIT("%s: FEC %llu: failed to correct: %d", v->data_dev->name, (unsigned long long)rsb, r); @@ -269,7 +269,7 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io, &is_zero) == 0) { /* skip known zero blocks entirely */ if (is_zero) - continue; + goto done; /* * skip if we have already found the theoretical -- cgit v1.2.3-70-g09d2