In a06ec283e125 next_id, folder_count, and file_count in the super block info were expanded to 64 bits, and BUG_ONs were added to detect overflow. This triggered an error reported by syzbot: if the MDB is corrupted, the BUG_ON is triggered. This patch replaces this mechanism with proper error handling and resolves the syzbot reported bug. Singed-off-by: Jori Koolstra Reported-by: syzbot+17cc9bb6d8d69b4139f0@syzkaller.appspotmail.com Closes: https://syzbot.org/bug?extid=17cc9bb6d8d69b4139f0 Signed-off-by: Jori Koolstra --- fs/hfs/dir.c | 12 ++++++------ fs/hfs/hfs.h | 3 +++ fs/hfs/hfs_fs.h | 2 +- fs/hfs/inode.c | 40 ++++++++++++++++++++++++++++++++-------- fs/hfs/mdb.c | 15 ++++++++++++--- 5 files changed, 54 insertions(+), 18 deletions(-) diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c index 86a6b317b474..03881a91f869 100644 --- a/fs/hfs/dir.c +++ b/fs/hfs/dir.c @@ -196,8 +196,8 @@ static int hfs_create(struct mnt_idmap *idmap, struct inode *dir, int res; inode = hfs_new_inode(dir, &dentry->d_name, mode); - if (!inode) - return -ENOMEM; + if (IS_ERR(inode)) + return PTR_ERR(inode); res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode); if (res) { @@ -226,8 +226,8 @@ static struct dentry *hfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, int res; inode = hfs_new_inode(dir, &dentry->d_name, S_IFDIR | mode); - if (!inode) - return ERR_PTR(-ENOMEM); + if (IS_ERR(inode)) + return ERR_CAST(inode); res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode); if (res) { @@ -264,9 +264,9 @@ static int hfs_remove(struct inode *dir, struct dentry *dentry) return res; clear_nlink(inode); inode_set_ctime_current(inode); - hfs_delete_inode(inode); + res = hfs_delete_inode(inode); mark_inode_dirty(inode); - return 0; + return res; } /* diff --git a/fs/hfs/hfs.h b/fs/hfs/hfs.h index 6f194d0768b6..4b4797ef4e50 100644 --- a/fs/hfs/hfs.h +++ b/fs/hfs/hfs.h @@ -287,3 +287,6 @@ struct hfs_readdir_data { }; #endif + + +#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */ diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h index fff149af89da..21dfdde71b14 100644 --- a/fs/hfs/hfs_fs.h +++ b/fs/hfs/hfs_fs.h @@ -182,7 +182,7 @@ extern void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext, __be32 log_size, __be32 phys_size, u32 clump_size); extern struct inode *hfs_iget(struct super_block *, struct hfs_cat_key *, hfs_cat_rec *); extern void hfs_evict_inode(struct inode *); -extern void hfs_delete_inode(struct inode *); +extern int hfs_delete_inode(struct inode *); /* attr.c */ extern const struct xattr_handler * const hfs_xattr_handlers[]; diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c index 9cd449913dc8..ce27d49c41e4 100644 --- a/fs/hfs/inode.c +++ b/fs/hfs/inode.c @@ -186,16 +186,22 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t s64 next_id; s64 file_count; s64 folder_count; + int err = -ENOMEM; if (!inode) - return NULL; + goto out_err; + + err = -EFSCORRUPTED; mutex_init(&HFS_I(inode)->extents_lock); INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list); spin_lock_init(&HFS_I(inode)->open_dir_lock); hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name); next_id = atomic64_inc_return(&HFS_SB(sb)->next_id); - BUG_ON(next_id > U32_MAX); + if (next_id > U32_MAX) { + pr_err("next CNID exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + goto out_discard; + } inode->i_ino = (u32)next_id; inode->i_mode = mode; inode->i_uid = current_fsuid(); @@ -209,7 +215,10 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t if (S_ISDIR(mode)) { inode->i_size = 2; folder_count = atomic64_inc_return(&HFS_SB(sb)->folder_count); - BUG_ON(folder_count > U32_MAX); + if (folder_count > U32_MAX) { + pr_err("folder count exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + goto out_discard; + } if (dir->i_ino == HFS_ROOT_CNID) HFS_SB(sb)->root_dirs++; inode->i_op = &hfs_dir_inode_operations; @@ -219,7 +228,10 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t } else if (S_ISREG(mode)) { HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks; file_count = atomic64_inc_return(&HFS_SB(sb)->file_count); - BUG_ON(file_count > U32_MAX); + if (file_count > U32_MAX) { + pr_err("file count exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + goto out_discard; + } if (dir->i_ino == HFS_ROOT_CNID) HFS_SB(sb)->root_files++; inode->i_op = &hfs_file_inode_operations; @@ -243,24 +255,35 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t hfs_mark_mdb_dirty(sb); return inode; + + out_discard: + iput(inode); + out_err: + return ERR_PTR(err); } -void hfs_delete_inode(struct inode *inode) +int hfs_delete_inode(struct inode *inode) { struct super_block *sb = inode->i_sb; hfs_dbg("ino %lu\n", inode->i_ino); if (S_ISDIR(inode->i_mode)) { - BUG_ON(atomic64_read(&HFS_SB(sb)->folder_count) > U32_MAX); + if (atomic64_read(&HFS_SB(sb)->folder_count) > U32_MAX) { + pr_err("folder count exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + return -EFSCORRUPTED; + } atomic64_dec(&HFS_SB(sb)->folder_count); if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID)) HFS_SB(sb)->root_dirs--; set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags); hfs_mark_mdb_dirty(sb); - return; + return 0; } - BUG_ON(atomic64_read(&HFS_SB(sb)->file_count) > U32_MAX); + if (atomic64_read(&HFS_SB(sb)->file_count) > U32_MAX) { + pr_err("file count exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + return -EFSCORRUPTED; + } atomic64_dec(&HFS_SB(sb)->file_count); if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID)) HFS_SB(sb)->root_files--; @@ -272,6 +295,7 @@ void hfs_delete_inode(struct inode *inode) } set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags); hfs_mark_mdb_dirty(sb); + return 0; } void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext, diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c index 53f3fae60217..45b690ab4ba5 100644 --- a/fs/hfs/mdb.c +++ b/fs/hfs/mdb.c @@ -273,15 +273,24 @@ void hfs_mdb_commit(struct super_block *sb) /* These parameters may have been modified, so write them back */ mdb->drLsMod = hfs_mtime(); mdb->drFreeBks = cpu_to_be16(HFS_SB(sb)->free_ablocks); - BUG_ON(atomic64_read(&HFS_SB(sb)->next_id) > U32_MAX); + if (atomic64_read(&HFS_SB(sb)->next_id) > U32_MAX) { + pr_err("next CNID exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + return; + } mdb->drNxtCNID = cpu_to_be32((u32)atomic64_read(&HFS_SB(sb)->next_id)); mdb->drNmFls = cpu_to_be16(HFS_SB(sb)->root_files); mdb->drNmRtDirs = cpu_to_be16(HFS_SB(sb)->root_dirs); - BUG_ON(atomic64_read(&HFS_SB(sb)->file_count) > U32_MAX); + if (atomic64_read(&HFS_SB(sb)->file_count) > U32_MAX) { + pr_err("file count exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + return; + } mdb->drFilCnt = cpu_to_be32((u32)atomic64_read(&HFS_SB(sb)->file_count)); - BUG_ON(atomic64_read(&HFS_SB(sb)->folder_count) > U32_MAX); + if (atomic64_read(&HFS_SB(sb)->folder_count) > U32_MAX) { + pr_err("folder count exceeds limit — filesystem corrupted. It is recommended to run fsck\n"); + return; + } mdb->drDirCnt = cpu_to_be32((u32)atomic64_read(&HFS_SB(sb)->folder_count)); -- 2.51.2