From b3885bd6edb41b91a0e3976469f72ae31bfb8d95 Mon Sep 17 00:00:00 2001 From: Hirofumi Nakagawa Date: Tue, 26 Sep 2017 03:09:53 +0900 Subject: ovl: add NULL check in ovl_alloc_inode This was detected by fault injection test Signed-off-by: Hirofumi Nakagawa Fixes: 13cf199d0088 ("ovl: allocate an ovl_inode struct") Cc: # v4.13 --- fs/overlayfs/super.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 092d150..f5738e9 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -174,6 +174,9 @@ static struct inode *ovl_alloc_inode(struct super_block *sb) { struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL); + if (!oi) + return NULL; + oi->cache = NULL; oi->redirect = NULL; oi->version = 0; -- cgit v1.1 From 0ce5cdc9d79277e55c3d80bf7d2b1adea2752078 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 22 Sep 2017 23:45:18 +0300 Subject: ovl: Return -ENOMEM if an allocation fails ovl_lookup() The error code is missing here so it means we return ERR_PTR(0) or NULL. The other error paths all return an error code so this probably should as well. Fixes: 02b69b284cd7 ("ovl: lookup redirects") Signed-off-by: Dan Carpenter Reviewed-by: Chandan Rajendra Signed-off-by: Miklos Szeredi --- fs/overlayfs/namei.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 654bea1..e081641 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -635,6 +635,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, } if (d.redirect) { + err = -ENOMEM; upperredirect = kstrdup(d.redirect, GFP_KERNEL); if (!upperredirect) goto out_put_upper; -- cgit v1.1 From 6eaf011144af10cad34c0d46f82e50d382c8e926 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Thu, 12 Oct 2017 19:03:04 +0300 Subject: ovl: fix EIO from lookup of non-indexed upper Commit fbaf94ee3cd5 ("ovl: don't set origin on broken lower hardlink") attempt to avoid the condition of non-indexed upper inode with lower hardlink as origin. If this condition is found, lookup returns EIO. The protection of commit mentioned above does not cover the case of lower that is not a hardlink when it is copied up (with either index=off/on) and then lower is hardlinked while overlay is offline. Changes to lower layer while overlayfs is offline should not result in unexpected behavior, so a permanent EIO error after creating a link in lower layer should not be considered as correct behavior. This fix replaces EIO error with success in cases where upper has origin but no index is found, or index is found that does not match upper inode. In those cases, lookup will not fail and the returned overlay inode will be hashed by upper inode instead of by lower origin inode. Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin") Cc: # v4.13 Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/overlayfs/inode.c | 20 ++++++++++++++++---- fs/overlayfs/namei.c | 20 ++++++++------------ fs/overlayfs/overlayfs.h | 3 ++- 3 files changed, 26 insertions(+), 17 deletions(-) diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index a619add..321511e 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -598,18 +598,30 @@ static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry, return true; } -struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry) +struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry, + struct dentry *index) { struct dentry *lowerdentry = ovl_dentry_lower(dentry); struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL; struct inode *inode; + /* Already indexed or could be indexed on copy up? */ + bool indexed = (index || (ovl_indexdir(dentry->d_sb) && !upperdentry)); + + if (WARN_ON(upperdentry && indexed && !lowerdentry)) + return ERR_PTR(-EIO); if (!realinode) realinode = d_inode(lowerdentry); - if (!S_ISDIR(realinode->i_mode) && - (upperdentry || (lowerdentry && ovl_indexdir(dentry->d_sb)))) { - struct inode *key = d_inode(lowerdentry ?: upperdentry); + /* + * Copy up origin (lower) may exist for non-indexed upper, but we must + * not use lower as hash key in that case. + * Hash inodes that are or could be indexed by origin inode and + * non-indexed upper inodes that could be hard linked by upper inode. + */ + if (!S_ISDIR(realinode->i_mode) && (upperdentry || indexed)) { + struct inode *key = d_inode(indexed ? lowerdentry : + upperdentry); unsigned int nlink; inode = iget5_locked(dentry->d_sb, (unsigned long) key, diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index e081641..05e9a0a 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -516,18 +516,9 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry, inode = d_inode(index); if (d_is_negative(index)) { - if (upper && d_inode(origin)->i_nlink > 1) { - pr_warn_ratelimited("overlayfs: hard link with origin but no index (ino=%lu).\n", - d_inode(origin)->i_ino); - goto fail; - } - - dput(index); - index = NULL; + goto out_dput; } else if (upper && d_inode(upper) != inode) { - pr_warn_ratelimited("overlayfs: wrong index found (index=%pd2, ino=%lu, upper ino=%lu).\n", - index, inode->i_ino, d_inode(upper)->i_ino); - goto fail; + goto out_dput; } else if (ovl_dentry_weird(index) || ovl_is_whiteout(index) || ((inode->i_mode ^ d_inode(origin)->i_mode) & S_IFMT)) { /* @@ -547,6 +538,11 @@ out: kfree(name.name); return index; +out_dput: + dput(index); + index = NULL; + goto out; + fail: dput(index); index = ERR_PTR(-EIO); @@ -710,7 +706,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, upperdentry = dget(index); if (upperdentry || ctr) { - inode = ovl_get_inode(dentry, upperdentry); + inode = ovl_get_inode(dentry, upperdentry, index); err = PTR_ERR(inode); if (IS_ERR(inode)) goto out_free_oe; diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index c706a6f..d9a0edd 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -286,7 +286,8 @@ int ovl_update_time(struct inode *inode, struct timespec *ts, int flags); bool ovl_is_private_xattr(const char *name); struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); -struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry); +struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry, + struct dentry *index); static inline void ovl_copyattr(struct inode *from, struct inode *to) { to->i_uid = from->i_uid; -- cgit v1.1 From 7937a56fdf0b064c2ffa33025210f725a4ebc822 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Fri, 20 Oct 2017 17:19:06 +0300 Subject: ovl: handle ENOENT on index lookup Treat ENOENT from index entry lookup the same way as treating a returned negative dentry. Apparently, either could be returned if file is not found, depending on the underlying file system. Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin") Cc: # v4.13 Signed-off-by: Amir Goldstein --- fs/overlayfs/namei.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 05e9a0a..0d9b8ce 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -507,6 +507,10 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry, index = lookup_one_len_unlocked(name.name, ofs->indexdir, name.len); if (IS_ERR(index)) { err = PTR_ERR(index); + if (err == -ENOENT) { + index = NULL; + goto out; + } pr_warn_ratelimited("overlayfs: failed inode index lookup (ino=%lu, key=%*s, err=%i);\n" "overlayfs: mount with '-o index=off' to disable inodes index.\n", d_inode(origin)->i_ino, name.len, name.name, -- cgit v1.1 From fa0096e3bad69ed6f34843fd7ae1c45ca987012a Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Tue, 24 Oct 2017 12:24:11 +0300 Subject: ovl: do not cleanup unsupported index entries With index=on, ovl_indexdir_cleanup() tries to cleanup invalid index entries (e.g. bad index name). This behavior could result in cleaning of entries created by newer kernels and is therefore undesirable. Instead, abort mount if such entries are encountered. We still cleanup 'stale' entries and 'orphan' entries, both those cases can be a result of offline changes to lower and upper dirs. When encoutering an index entry of type directory or whiteout, kernel was supposed to fallback to read-only mount, but the fill_super() operation returns EROFS in this case instead of returning success with read-only mount flag, so mount fails when encoutering directory or whiteout index entries. Bless this behavior by returning -EINVAL on directory and whiteout index entries as we do for all unsupported index entries. Fixes: 61b674710cd9 ("ovl: do not cleanup directory and whiteout index..") Cc: # v4.13 Signed-off-by: Amir Goldstein --- fs/overlayfs/namei.c | 7 +++---- fs/overlayfs/readdir.c | 11 +++++------ 2 files changed, 8 insertions(+), 10 deletions(-) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 0d9b8ce..a12dc10 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -405,14 +405,13 @@ int ovl_verify_index(struct dentry *index, struct path *lowerstack, * be treated as stale (i.e. after unlink of the overlay inode). * We don't know the verification rules for directory and whiteout * index entries, because they have not been implemented yet, so return - * EROFS if those entries are found to avoid corrupting an index that - * was created by a newer kernel. + * EINVAL if those entries are found to abort the mount to avoid + * corrupting an index that was created by a newer kernel. */ - err = -EROFS; + err = -EINVAL; if (d_is_dir(index) || ovl_is_whiteout(index)) goto fail; - err = -EINVAL; if (index->d_name.len < sizeof(struct ovl_fh)*2) goto fail; diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 0f85ee9..698b74d 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -1021,13 +1021,12 @@ int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt, break; } err = ovl_verify_index(index, lowerstack, numlower); - if (err) { - if (err == -EROFS) - break; + /* Cleanup stale and orphan index entries */ + if (err && (err == -ESTALE || err == -ENOENT)) err = ovl_cleanup(dir, index); - if (err) - break; - } + if (err) + break; + dput(index); index = NULL; } -- cgit v1.1