Re: [PATCH] hfsplus: fix uninit-value in hfsplus_delete_cat()
From: Viacheslav Dubeyko
Date: Wed Dec 14 2022 - 14:19:22 EST
> On Dec 14, 2022, at 2:37 AM, ChenXiaoSong <chenxiaosong2@xxxxxxxxxx> wrote:
>
> Syzkaller reported BUG as follows:
>
> =====================================================
> BUG: KMSAN: uninit-value in hfsplus_subfolders_dec
> fs/hfsplus/catalog.c:248 [inline]
> BUG: KMSAN: uninit-value in hfsplus_delete_cat+0x1207/0x14d0
> fs/hfsplus/catalog.c:419
> hfsplus_subfolders_dec fs/hfsplus/catalog.c:248 [inline]
> hfsplus_delete_cat+0x1207/0x14d0 fs/hfsplus/catalog.c:419
> hfsplus_rmdir+0x141/0x3d0 fs/hfsplus/dir.c:425
> hfsplus_rename+0x102/0x2e0 fs/hfsplus/dir.c:545
> vfs_rename+0x1e4c/0x2800 fs/namei.c:4779
> do_renameat2+0x173d/0x1dc0 fs/namei.c:4930
> __do_sys_renameat2 fs/namei.c:4963 [inline]
> __se_sys_renameat2 fs/namei.c:4960 [inline]
> __ia32_sys_renameat2+0x14b/0x1f0 fs/namei.c:4960
> do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
> __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
> do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
> do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
> entry_SYSENTER_compat_after_hwframe+0x70/0x82
>
> Uninit was stored to memory at:
> hfsplus_subfolders_inc fs/hfsplus/catalog.c:232 [inline]
> hfsplus_create_cat+0x19e3/0x19f0 fs/hfsplus/catalog.c:314
> hfsplus_mknod+0x1fd/0x560 fs/hfsplus/dir.c:494
> hfsplus_mkdir+0x54/0x60 fs/hfsplus/dir.c:529
> vfs_mkdir+0x62a/0x870 fs/namei.c:4036
> do_mkdirat+0x466/0x7b0 fs/namei.c:4061
> __do_sys_mkdirat fs/namei.c:4076 [inline]
> __se_sys_mkdirat fs/namei.c:4074 [inline]
> __ia32_sys_mkdirat+0xc4/0x120 fs/namei.c:4074
> do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
> __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
> do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
> do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
> entry_SYSENTER_compat_after_hwframe+0x70/0x82
>
> Uninit was created at:
> __alloc_pages+0x9f1/0xe80 mm/page_alloc.c:5581
> alloc_pages+0xaae/0xd80 mm/mempolicy.c:2285
> alloc_slab_page mm/slub.c:1794 [inline]
> allocate_slab+0x1b5/0x1010 mm/slub.c:1939
> new_slab mm/slub.c:1992 [inline]
> ___slab_alloc+0x10c3/0x2d60 mm/slub.c:3180
> __slab_alloc mm/slub.c:3279 [inline]
> slab_alloc_node mm/slub.c:3364 [inline]
> slab_alloc mm/slub.c:3406 [inline]
> __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
> kmem_cache_alloc_lru+0x6f3/0xb30 mm/slub.c:3429
> alloc_inode_sb include/linux/fs.h:3125 [inline]
> hfsplus_alloc_inode+0x56/0xc0 fs/hfsplus/super.c:627
> alloc_inode+0x83/0x440 fs/inode.c:259
> iget_locked+0x2a1/0xe20 fs/inode.c:1286
> hfsplus_iget+0x5f/0xb60 fs/hfsplus/super.c:64
> hfsplus_btree_open+0x13b/0x1cf0 fs/hfsplus/btree.c:150
> hfsplus_fill_super+0x12b0/0x2a80 fs/hfsplus/super.c:473
> mount_bdev+0x508/0x840 fs/super.c:1401
> hfsplus_mount+0x49/0x60 fs/hfsplus/super.c:641
> legacy_get_tree+0x10c/0x280 fs/fs_context.c:610
> vfs_get_tree+0xa1/0x500 fs/super.c:1531
> do_new_mount+0x694/0x1580 fs/namespace.c:3040
> path_mount+0x71a/0x1eb0 fs/namespace.c:3370
> do_mount fs/namespace.c:3383 [inline]
> __do_sys_mount fs/namespace.c:3591 [inline]
> __se_sys_mount+0x734/0x840 fs/namespace.c:3568
> __ia32_sys_mount+0xdf/0x140 fs/namespace.c:3568
> do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
> __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
> do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
> do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
> entry_SYSENTER_compat_after_hwframe+0x70/0x82
> =====================================================
>
> Fix this by initializing 'subfolders' of 'struct hfsplus_inode_info'
> in hfsplus_iget().
>
> Link: https://syzkaller.appspot.com/bug?id=981f82f21b973f2f5663dfea581ff8cee1ddfef2
> Signed-off-by: ChenXiaoSong <chenxiaosong2@xxxxxxxxxx>
> ---
> fs/hfsplus/super.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
> index 122ed89ebf9f..612c07857667 100644
> --- a/fs/hfsplus/super.c
> +++ b/fs/hfsplus/super.c
> @@ -72,6 +72,7 @@ struct inode *hfsplus_iget(struct super_block *sb, unsigned long ino)
> mutex_init(&HFSPLUS_I(inode)->extents_lock);
> HFSPLUS_I(inode)->flags = 0;
> HFSPLUS_I(inode)->extent_state = 0;
> + HFSPLUS_I(inode)->subfolders = 0;
> HFSPLUS_I(inode)->rsrc_inode = NULL;
> atomic_set(&HFSPLUS_I(inode)->opencnt, 0);
>
Looks good. Thanks for the fix.
Reviewed-by: Viacheslav Dubeyko <slava@xxxxxxxxxxx>
But we have more fields in struct hfsplus_inode_info:
struct hfsplus_inode_info {
atomic_t opencnt;
/*
* Extent allocation information, protected by extents_lock.
*/
u32 first_blocks;
u32 clump_blocks;
u32 alloc_blocks;
u32 cached_start;
u32 cached_blocks;
hfsplus_extent_rec first_extents;
hfsplus_extent_rec cached_extents;
unsigned int extent_state;
struct mutex extents_lock;
/*
* Immutable data.
*/
struct inode *rsrc_inode;
__be32 create_date;
/*
* Protected by sbi->vh_mutex.
*/
u32 linkid;
/*
* Accessed using atomic bitops.
*/
unsigned long flags;
/*
* Protected by i_mutex.
*/
sector_t fs_blocks;
u8 userflags; /* BSD user file flags */
u32 subfolders; /* Subfolder count (HFSX only) */
struct list_head open_dir_list;
spinlock_t open_dir_lock;
loff_t phys_size;
struct inode vfs_inode;
};
I believe we need to set initialized more fields in hfsplus_iget() method.
Could you add the initialization of other missed fields?
Thanks,
Slava.
> --
> 2.31.1
>