#syz test
On Sat, Oct 5, 2024 at 11:32 PM syzbot
<syzbot+01218003be74b5e1213a@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: e32cde8d2bd7 Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=16cf7dd0580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=b1fd45f2013d812f
> dashboard link: https://syzkaller.appspot.com/bug?extid=01218003be74b5e1213a
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11cf7dd0580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d06580580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/16d4da549bf4/disk-e32cde8d.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/a01bc9a0e174/vmlinux-e32cde8d.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/93f4dfad6909/bzImage-e32cde8d.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/433ba0700154/mount_0.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+01218003be74b5e1213a@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> exFAT-fs (loop0): failed to load upcase table (idx : 0x00010000, chksum : 0x726052d3, utbl_chksum : 0xe619d30d)
> =====================================================
> BUG: KMSAN: uninit-value in __exfat_get_dentry_set+0x10ca/0x14d0 fs/exfat/dir.c:804
> __exfat_get_dentry_set+0x10ca/0x14d0 fs/exfat/dir.c:804
> exfat_get_dentry_set+0x58/0xec0 fs/exfat/dir.c:859
> __exfat_write_inode+0x3c1/0xe30 fs/exfat/inode.c:46
> __exfat_truncate+0x7f3/0xbb0 fs/exfat/file.c:211
> exfat_truncate+0xee/0x2a0 fs/exfat/file.c:257
> exfat_write_failed fs/exfat/inode.c:421 [inline]
> exfat_direct_IO+0x5a3/0x900 fs/exfat/inode.c:485
> generic_file_direct_write+0x275/0x6a0 mm/filemap.c:3977
> __generic_file_write_iter+0x242/0x460 mm/filemap.c:4141
> exfat_file_write_iter+0x894/0xfb0 fs/exfat/file.c:598
> do_iter_readv_writev+0x88a/0xa30
> vfs_writev+0x56a/0x14f0 fs/read_write.c:1064
> do_pwritev fs/read_write.c:1165 [inline]
> __do_sys_pwritev2 fs/read_write.c:1224 [inline]
> __se_sys_pwritev2+0x280/0x470 fs/read_write.c:1215
> __x64_sys_pwritev2+0x11f/0x1a0 fs/read_write.c:1215
> x64_sys_call+0x2edb/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:329
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Uninit was stored to memory at:
> memcpy_to_iter lib/iov_iter.c:65 [inline]
> iterate_bvec include/linux/iov_iter.h:123 [inline]
> iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
> iterate_and_advance include/linux/iov_iter.h:328 [inline]
> _copy_to_iter+0xe53/0x2b30 lib/iov_iter.c:185
> copy_page_to_iter+0x419/0x880 lib/iov_iter.c:362
> shmem_file_read_iter+0xa09/0x12b0 mm/shmem.c:3167
> do_iter_readv_writev+0x88a/0xa30
> vfs_iter_read+0x278/0x760 fs/read_write.c:923
> lo_read_simple drivers/block/loop.c:283 [inline]
> do_req_filebacked drivers/block/loop.c:516 [inline]
> loop_handle_cmd drivers/block/loop.c:1910 [inline]
> loop_process_work+0x20fc/0x3750 drivers/block/loop.c:1945
> loop_rootcg_workfn+0x2b/0x40 drivers/block/loop.c:1976
> process_one_work kernel/workqueue.c:3229 [inline]
> process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
> worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
> kthread+0x3e2/0x540 kernel/kthread.c:389
> ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> Uninit was stored to memory at:
> memcpy_from_iter lib/iov_iter.c:73 [inline]
> iterate_bvec include/linux/iov_iter.h:123 [inline]
> iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
> iterate_and_advance include/linux/iov_iter.h:328 [inline]
> __copy_from_iter lib/iov_iter.c:249 [inline]
> copy_page_from_iter_atomic+0x12b7/0x3100 lib/iov_iter.c:481
> copy_folio_from_iter_atomic include/linux/uio.h:201 [inline]
> generic_perform_write+0x8d1/0x1080 mm/filemap.c:4066
> shmem_file_write_iter+0x2ba/0x2f0 mm/shmem.c:3221
> do_iter_readv_writev+0x88a/0xa30
> vfs_iter_write+0x44d/0xd40 fs/read_write.c:988
> lo_write_bvec drivers/block/loop.c:243 [inline]
> lo_write_simple drivers/block/loop.c:264 [inline]
> do_req_filebacked drivers/block/loop.c:511 [inline]
> loop_handle_cmd drivers/block/loop.c:1910 [inline]
> loop_process_work+0x15e6/0x3750 drivers/block/loop.c:1945
> loop_rootcg_workfn+0x2b/0x40 drivers/block/loop.c:1976
> process_one_work kernel/workqueue.c:3229 [inline]
> process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
> worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
> kthread+0x3e2/0x540 kernel/kthread.c:389
> ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> Uninit was created at:
> __alloc_pages_noprof+0x9d6/0xe70 mm/page_alloc.c:4756
> alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
> alloc_pages_noprof mm/mempolicy.c:2345 [inline]
> folio_alloc_noprof+0x1db/0x310 mm/mempolicy.c:2352
> filemap_alloc_folio_noprof+0xa6/0x440 mm/filemap.c:1010
> __filemap_get_folio+0xac4/0x1550 mm/filemap.c:1952
> block_write_begin+0x6e/0x2b0 fs/buffer.c:2226
> exfat_write_begin+0xfb/0x400 fs/exfat/inode.c:434
> exfat_extend_valid_size fs/exfat/file.c:553 [inline]
> exfat_file_write_iter+0x474/0xfb0 fs/exfat/file.c:588
> do_iter_readv_writev+0x88a/0xa30
> vfs_writev+0x56a/0x14f0 fs/read_write.c:1064
> do_pwritev fs/read_write.c:1165 [inline]
> __do_sys_pwritev2 fs/read_write.c:1224 [inline]
> __se_sys_pwritev2+0x280/0x470 fs/read_write.c:1215
> __x64_sys_pwritev2+0x11f/0x1a0 fs/read_write.c:1215
> x64_sys_call+0x2edb/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:329
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> CPU: 0 UID: 0 PID: 5188 Comm: syz-executor221 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
> =====================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
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> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
>
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>
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>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
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>
> If the report is a duplicate of another one, reply with:
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>
> If you want to undo deduplication, reply with:
> #syz undup
From bc385ee8fcef08d83d709415d500ef2e2ac87457 Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@kernel.org>
Date: Tue, 29 Oct 2024 10:22:31 +0900
Subject: [PATCH] exfat: fix uninit-value in __exfat_get_dentry_set
There is no check if stream size and start_clu are invalid.
If start_clu is EOF cluster and stream size is 4096, It will cause
uninit value access. because ei->hint_femp.eidx could be 128(if cluster
size is 4K) and wrong hint will allocate next cluster. and this cluster
will be same with the cluster that is allocated by
exfat_extend_valid_size(). The previous patch will check invalid start_clu,
but for clarity, Initialize hint_femp.eidx to zero.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
fs/exfat/namei.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index 2c4c44229352..c5302b914066 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -345,6 +345,7 @@ static int exfat_find_empty_entry(struct inode *inode,
if (ei->start_clu == EXFAT_EOF_CLUSTER) {
ei->start_clu = clu.dir;
p_dir->dir = clu.dir;
+ hint_femp.eidx = 0;
}
/* append to the FAT chain */
--
2.34.1
