[PATCH openEuler-1.0-LTS] ext4: avoid infinite loops caused by residual data
mainline inclusion from mainline-v7.0-rc6 commit 5422fe71d26d42af6c454ca9527faaad4e677d6c category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14191 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- On the mkdir/mknod path, when mapping logical blocks to physical blocks, if inserting a new extent into the extent tree fails (in this example, because the file system disabled the huge file feature when marking the inode as dirty), ext4_ext_map_blocks() only calls ext4_free_blocks() to reclaim the physical block without deleting the corresponding data in the extent tree. This causes subsequent mkdir operations to reference the previously reclaimed physical block number again, even though this physical block is already being used by the xattr block. Therefore, a situation arises where both the directory and xattr are using the same buffer head block in memory simultaneously. The above causes ext4_xattr_block_set() to enter an infinite loop about "inserted" and cannot release the inode lock, ultimately leading to the 143s blocking problem mentioned in [1]. If the metadata is corrupted, then trying to remove some extent space can do even more harm. Also in case EXT4_GET_BLOCKS_DELALLOC_RESERVE was passed, remove space wrongly update quota information. Jan Kara suggests distinguishing between two cases: 1) The error is ENOSPC or EDQUOT - in this case the filesystem is fully consistent and we must maintain its consistency including all the accounting. However these errors can happen only early before we've inserted the extent into the extent tree. So current code works correctly for this case. 2) Some other error - this means metadata is corrupted. We should strive to do as few modifications as possible to limit damage. So I'd just skip freeing of allocated blocks. [1] INFO: task syz.0.17:5995 blocked for more than 143 seconds. Call Trace: inode_lock_nested include/linux/fs.h:1073 [inline] __start_dirop fs/namei.c:2923 [inline] start_dirop fs/namei.c:2934 [inline] Reported-by: syzbot+512459401510e2a9a39f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=1659aaaaa8d9d11265d7 Tested-by: syzbot+1659aaaaa8d9d11265d7@syzkaller.appspotmail.com Reported-by: syzbot+1659aaaaa8d9d11265d7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=512459401510e2a9a39f Tested-by: syzbot+1659aaaaa8d9d11265d7@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis <eadavis@qq.com> Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: syzbot+512459401510e2a9a39f@syzkaller.appspotmail.com Link: https://patch.msgid.link/tencent_43696283A68450B761D76866C6F360E36705@qq.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Conflicts: fs/ext4/extents.c [ctx conflicts] Signed-off-by: Lai Zewei <laizewei3@huawei.com> --- fs/ext4/extents.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 5f2654bfe2f1..bf1d315f9178 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4672,7 +4672,12 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags); - if (err && free_on_err) { + /* + * Gracefully handle out of space conditions. If the filesystem + * is inconsistent, we'll just leak allocated blocks to avoid + * causing even more damage. + */ + if (err && free_on_err && (err == -EDQUOT || err == -ENOSPC)) { int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ? EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0; /* free data blocks we just allocated */ -- 2.52.0
mainline inclusion from mainline-v7.0-rc5 commit 5133b61aaf437e5f25b1b396b14242a6bb0508e2 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14128 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The NFSv4.0 replay cache uses a fixed 112-byte inline buffer (rp_ibuf[NFSD4_REPLAY_ISIZE]) to store encoded operation responses. This size was calculated based on OPEN responses and does not account for LOCK denied responses, which include the conflicting lock owner as a variable-length field up to 1024 bytes (NFS4_OPAQUE_LIMIT). When a LOCK operation is denied due to a conflict with an existing lock that has a large owner, nfsd4_encode_operation() copies the full encoded response into the undersized replay buffer via read_bytes_from_xdr_buf() with no bounds check. This results in a slab-out-of-bounds write of up to 944 bytes past the end of the buffer, corrupting adjacent heap memory. This can be triggered remotely by an unauthenticated attacker with two cooperating NFSv4.0 clients: one sets a lock with a large owner string, then the other requests a conflicting lock to provoke the denial. We could fix this by increasing NFSD4_REPLAY_ISIZE to allow for a full opaque, but that would increase the size of every stateowner, when most lockowners are not that large. Instead, fix this by checking the encoded response length against NFSD4_REPLAY_ISIZE before copying into the replay buffer. If the response is too large, set rp_buflen to 0 to skip caching the replay payload. The status is still cached, and the client already received the correct response on the original request. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@kernel.org Reported-by: Nicholas Carlini <npc@anthropic.com> Tested-by: Nicholas Carlini <npc@anthropic.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Conflicts: fs/nfsd/nfs4xdr.c fs/nfsd/state.h [ctx conflicts] Signed-off-by: Lai Zewei <laizewei3@huawei.com> --- fs/nfsd/nfs4xdr.c | 11 ++++++++--- fs/nfsd/state.h | 17 ++++++++++++----- 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 645a3d4807b8..dab375230703 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -4459,9 +4459,14 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op) int len = xdr->buf->len - post_err_offset; so->so_replay.rp_status = op->status; - so->so_replay.rp_buflen = len; - read_bytes_from_xdr_buf(xdr->buf, post_err_offset, - so->so_replay.rp_buf, len); + if (len <= NFSD4_REPLAY_ISIZE) { + so->so_replay.rp_buflen = len; + read_bytes_from_xdr_buf(xdr->buf, + post_err_offset, + so->so_replay.rp_buf, len); + } else { + so->so_replay.rp_buflen = 0; + } } status: /* Note that op->status is already in network byte order: */ diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index 0f07ad6dc1ef..4dc8d2fdce0b 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -369,11 +369,18 @@ struct nfs4_client_reclaim { char cr_recdir[HEXDIR_LEN]; /* recover dir */ }; -/* A reasonable value for REPLAY_ISIZE was estimated as follows: - * The OPEN response, typically the largest, requires - * 4(status) + 8(stateid) + 20(changeinfo) + 4(rflags) + 8(verifier) + - * 4(deleg. type) + 8(deleg. stateid) + 4(deleg. recall flag) + - * 20(deleg. space limit) + ~32(deleg. ace) = 112 bytes +/* + * REPLAY_ISIZE is sized for an OPEN response with delegation: + * 4(status) + 8(stateid) + 20(changeinfo) + 4(rflags) + + * 8(verifier) + 4(deleg. type) + 8(deleg. stateid) + + * 4(deleg. recall flag) + 20(deleg. space limit) + + * ~32(deleg. ace) = 112 bytes + * + * Some responses can exceed this. A LOCK denial includes the conflicting + * lock owner, which can be up to 1024 bytes (NFS4_OPAQUE_LIMIT). Responses + * larger than REPLAY_ISIZE are not cached in rp_ibuf; only rp_status is + * saved. Enlarging this constant increases the size of every + * nfs4_stateowner. */ #define NFSD4_REPLAY_ISIZE 112 -- 2.52.0
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