From 2acf15b94d5b8ea8392c4b6753a6ffac3135cd78 Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Fri, 2 Jul 2021 12:07:43 +0800 Subject: [PATCH 1/3] reiserfs: add check for root_inode in reiserfs_fill_super Our syzcaller report a NULL pointer dereference: BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 116e95067 P4D 116e95067 PUD 1080b5067 PMD 0 Oops: 0010 [#1] SMP KASAN CPU: 7 PID: 592 Comm: a.out Not tainted 5.13.0-next-20210629-dirty #67 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-p4 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffff888114e779b8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff110229cef39 RCX: ffffffffaa67e1aa RDX: 0000000000000000 RSI: ffff88810a58ee00 RDI: ffff8881233180b0 RBP: ffffffffac38e9c0 R08: ffffffffaa67e17e R09: 0000000000000001 R10: ffffffffb91c5557 R11: fffffbfff7238aaa R12: ffff88810a58ee00 R13: ffff888114e77aa0 R14: 0000000000000000 R15: ffff8881233180b0 FS: 00007f946163c480(0000) GS:ffff88839f1c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001099c1000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lookup_slow+0x116/0x2d0 ? page_put_link+0x120/0x120 ? __d_lookup+0xfc/0x320 ? d_lookup+0x49/0x90 lookup_one_len+0x13c/0x170 ? __lookup_slow+0x2d0/0x2d0 ? reiserfs_schedule_old_flush+0x31/0x130 reiserfs_lookup_privroot+0x64/0x150 reiserfs_fill_super+0x158c/0x1b90 ? finish_unfinished+0xb10/0xb10 ? bprintf+0xe0/0xe0 ? __mutex_lock_slowpath+0x30/0x30 ? __kasan_check_write+0x20/0x30 ? up_write+0x51/0xb0 ? set_blocksize+0x9f/0x1f0 mount_bdev+0x27c/0x2d0 ? finish_unfinished+0xb10/0xb10 ? reiserfs_kill_sb+0x120/0x120 get_super_block+0x19/0x30 legacy_get_tree+0x76/0xf0 vfs_get_tree+0x49/0x160 ? capable+0x1d/0x30 path_mount+0xacc/0x1380 ? putname+0x97/0xd0 ? finish_automount+0x450/0x450 ? kmem_cache_free+0xf8/0x5a0 ? putname+0x97/0xd0 do_mount+0xe2/0x110 ? path_mount+0x1380/0x1380 ? copy_mount_options+0x69/0x140 __x64_sys_mount+0xf0/0x190 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae This is because 'root_inode' is initialized with wrong mode, and it's i_op is set to 'reiserfs_special_inode_operations'. Thus add check for 'root_inode' to fix the problem. Link: https://lore.kernel.org/r/20210702040743.1918552-1-yukuai3@huawei.com Signed-off-by: Yu Kuai Signed-off-by: Jan Kara --- fs/reiserfs/super.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c index 3ffafc73acf0..58481f8d63d5 100644 --- a/fs/reiserfs/super.c +++ b/fs/reiserfs/super.c @@ -2082,6 +2082,14 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent) unlock_new_inode(root_inode); } + if (!S_ISDIR(root_inode->i_mode) || !inode_get_bytes(root_inode) || + !root_inode->i_size) { + SWARN(silent, s, "", "corrupt root inode, run fsck"); + iput(root_inode); + errval = -EUCLEAN; + goto error; + } + s->s_root = d_make_root(root_inode); if (!s->s_root) goto error; From 728d392f8a799f037812d0f2b254fb3b5e115fcf Mon Sep 17 00:00:00 2001 From: Javier Pello Date: Wed, 14 Jul 2021 18:54:48 +0200 Subject: [PATCH 2/3] fs/ext2: Avoid page_address on pages returned by ext2_get_page Commit 782b76d7abdf02b12c46ed6f1e9bf715569027f7 ("fs/ext2: Replace kmap() with kmap_local_page()") replaced the kmap/kunmap calls in ext2_get_page/ext2_put_page with kmap_local_page/kunmap_local for efficiency reasons. As a necessary side change, the commit also made ext2_get_page (and ext2_find_entry and ext2_dotdot) return the mapping address along with the page itself, as it is required for kunmap_local, and converted uses of page_address on such pages to use the newly returned address instead. However, uses of page_address on such pages were missed in ext2_check_page and ext2_delete_entry, which triggers oopses if kmap_local_page happens to return an address from high memory. Fix this now by converting the remaining uses of page_address to use the right address, as returned by kmap_local_page. Link: https://lore.kernel.org/r/20210714185448.8707ac239e9f12b3a7f5b9f9@urjc.es Reviewed-by: Ira Weiny Signed-off-by: Javier Pello Fixes: 782b76d7abdf ("fs/ext2: Replace kmap() with kmap_local_page()") Signed-off-by: Jan Kara --- fs/ext2/dir.c | 12 ++++++------ fs/ext2/ext2.h | 3 ++- fs/ext2/namei.c | 4 ++-- 3 files changed, 10 insertions(+), 9 deletions(-) diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c index 14292dba3a12..2c2f179b6977 100644 --- a/fs/ext2/dir.c +++ b/fs/ext2/dir.c @@ -106,12 +106,11 @@ static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) return err; } -static bool ext2_check_page(struct page *page, int quiet) +static bool ext2_check_page(struct page *page, int quiet, char *kaddr) { struct inode *dir = page->mapping->host; struct super_block *sb = dir->i_sb; unsigned chunk_size = ext2_chunk_size(dir); - char *kaddr = page_address(page); u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); unsigned offs, rec_len; unsigned limit = PAGE_SIZE; @@ -205,7 +204,8 @@ static struct page * ext2_get_page(struct inode *dir, unsigned long n, if (!IS_ERR(page)) { *page_addr = kmap_local_page(page); if (unlikely(!PageChecked(page))) { - if (PageError(page) || !ext2_check_page(page, quiet)) + if (PageError(page) || !ext2_check_page(page, quiet, + *page_addr)) goto fail; } } @@ -584,10 +584,10 @@ out_unlock: * ext2_delete_entry deletes a directory entry by merging it with the * previous entry. Page is up-to-date. */ -int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) +int ext2_delete_entry (struct ext2_dir_entry_2 *dir, struct page *page, + char *kaddr) { struct inode *inode = page->mapping->host; - char *kaddr = page_address(page); unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); unsigned to = ((char *)dir - kaddr) + ext2_rec_len_from_disk(dir->rec_len); @@ -607,7 +607,7 @@ int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) de = ext2_next_entry(de); } if (pde) - from = (char*)pde - (char*)page_address(page); + from = (char *)pde - kaddr; pos = page_offset(page) + from; lock_page(page); err = ext2_prepare_chunk(page, pos, to - from); diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h index b0a694820cb7..e512630cb63e 100644 --- a/fs/ext2/ext2.h +++ b/fs/ext2/ext2.h @@ -740,7 +740,8 @@ extern int ext2_inode_by_name(struct inode *dir, extern int ext2_make_empty(struct inode *, struct inode *); extern struct ext2_dir_entry_2 *ext2_find_entry(struct inode *, const struct qstr *, struct page **, void **res_page_addr); -extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *); +extern int ext2_delete_entry(struct ext2_dir_entry_2 *dir, struct page *page, + char *kaddr); extern int ext2_empty_dir (struct inode *); extern struct ext2_dir_entry_2 *ext2_dotdot(struct inode *dir, struct page **p, void **pa); extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, void *, diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c index 1f69b81655b6..5f6b7560eb3f 100644 --- a/fs/ext2/namei.c +++ b/fs/ext2/namei.c @@ -293,7 +293,7 @@ static int ext2_unlink(struct inode * dir, struct dentry *dentry) goto out; } - err = ext2_delete_entry (de, page); + err = ext2_delete_entry (de, page, page_addr); ext2_put_page(page, page_addr); if (err) goto out; @@ -397,7 +397,7 @@ static int ext2_rename (struct user_namespace * mnt_userns, old_inode->i_ctime = current_time(old_inode); mark_inode_dirty(old_inode); - ext2_delete_entry(old_de, old_page); + ext2_delete_entry(old_de, old_page, old_page_addr); if (dir_de) { if (old_dir != new_dir) From 13d257503c0930010ef9eed78b689cec417ab741 Mon Sep 17 00:00:00 2001 From: Shreyansh Chouhan Date: Fri, 9 Jul 2021 20:59:29 +0530 Subject: [PATCH 3/3] reiserfs: check directory items on read from disk While verifying the leaf item that we read from the disk, reiserfs doesn't check the directory items, this could cause a crash when we read a directory item from the disk that has an invalid deh_location. This patch adds a check to the directory items read from the disk that does a bounds check on deh_location for the directory entries. Any directory entry header with a directory entry offset greater than the item length is considered invalid. Link: https://lore.kernel.org/r/20210709152929.766363-1-chouhan.shreyansh630@gmail.com Reported-by: syzbot+c31a48e6702ccb3d64c9@syzkaller.appspotmail.com Signed-off-by: Shreyansh Chouhan Signed-off-by: Jan Kara --- fs/reiserfs/stree.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c index 476a7ff49482..ef42729216d1 100644 --- a/fs/reiserfs/stree.c +++ b/fs/reiserfs/stree.c @@ -387,6 +387,24 @@ void pathrelse(struct treepath *search_path) search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET; } +static int has_valid_deh_location(struct buffer_head *bh, struct item_head *ih) +{ + struct reiserfs_de_head *deh; + int i; + + deh = B_I_DEH(bh, ih); + for (i = 0; i < ih_entry_count(ih); i++) { + if (deh_location(&deh[i]) > ih_item_len(ih)) { + reiserfs_warning(NULL, "reiserfs-5094", + "directory entry location seems wrong %h", + &deh[i]); + return 0; + } + } + + return 1; +} + static int is_leaf(char *buf, int blocksize, struct buffer_head *bh) { struct block_head *blkh; @@ -454,11 +472,14 @@ static int is_leaf(char *buf, int blocksize, struct buffer_head *bh) "(second one): %h", ih); return 0; } - if (is_direntry_le_ih(ih) && (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE))) { - reiserfs_warning(NULL, "reiserfs-5093", - "item entry count seems wrong %h", - ih); - return 0; + if (is_direntry_le_ih(ih)) { + if (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE)) { + reiserfs_warning(NULL, "reiserfs-5093", + "item entry count seems wrong %h", + ih); + return 0; + } + return has_valid_deh_location(bh, ih); } prev_location = ih_location(ih); }