#syz test
From 4525458538ff5e5a4315fc85ac495adcb62e7724 Mon Sep 17 00:00:00 2001
From: Zhao Mengmeng <zhaomengmeng@xxxxxxxxxx>
Date: Fri, 30 Aug 2024 17:16:39 +0800
Subject: [PATCH] jfs: Fix uninit-value access of new_ea in ea_buffer
syzbot reports that lzo1x_1_do_compress is using uninit-value:
=====================================================
BUG: KMSAN: uninit-value in lzo1x_1_do_compress+0x19f9/0x2510 lib/lzo/lzo1x_compress.c:178
lzo1x_1_do_compress+0x19f9/0x2510 lib/lzo/lzo1x_compress.c:178
lzogeneric1x_1_compress+0x26a/0x11b0 lib/lzo/lzo1x_compress.c:333
lzo1x_1_compress+0x47/0x80 lib/lzo/lzo1x_compress.c:383
__lzo_compress crypto/lzo.c:58 [inline]
lzo_scompress+0x98/0x180 crypto/lzo.c:79
scomp_acomp_comp_decomp+0x7c6/0xb90
scomp_acomp_compress+0x32/0x40 crypto/scompress.c:187
crypto_acomp_compress include/crypto/acompress.h:251 [inline]
zswap_compress+0x368/0xad0 mm/zswap.c:927
zswap_store+0x1af3/0x2dd0 mm/zswap.c:1459
swap_writepage+0x11f/0x470 mm/page_io.c:198
shmem_writepage+0x1a75/0x1f70 mm/shmem.c:1536
pageout mm/vmscan.c:680 [inline]
shrink_folio_list+0x577f/0x7cb0 mm/vmscan.c:1360
evict_folios+0x9bce/0xbc80 mm/vmscan.c:4580
try_to_shrink_lruvec+0x13a3/0x1750 mm/vmscan.c:4775
shrink_one+0x646/0xd20 mm/vmscan.c:4813
shrink_many mm/vmscan.c:4876 [inline]
lru_gen_shrink_node mm/vmscan.c:4954 [inline]
shrink_node+0x451a/0x50f0 mm/vmscan.c:5934
kswapd_shrink_node mm/vmscan.c:6762 [inline]
balance_pgdat mm/vmscan.c:6954 [inline]
kswapd+0x257e/0x4290 mm/vmscan.c:7223
kthread+0x3dd/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:122 [inline]
iterate_and_advance2 include/linux/iov_iter.h:249 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
__copy_from_iter lib/iov_iter.c:249 [inline]
copy_page_from_iter_atomic+0x12bb/0x2ae0 lib/iov_iter.c:481
copy_folio_from_iter_atomic include/linux/uio.h:186 [inline]
generic_perform_write+0x896/0x12e0 mm/filemap.c:4032
shmem_file_write_iter+0x2bd/0x2f0 mm/shmem.c:3074
do_iter_readv_writev+0x8a1/0xa40
vfs_iter_write+0x459/0xd50 fs/read_write.c:895
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+0x15ec/0x3750 drivers/block/loop.c:1945
loop_rootcg_workfn+0x2b/0x40 drivers/block/loop.c:1976
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3312
worker_thread+0xea7/0x14d0 kernel/workqueue.c:3389
kthread+0x3dd/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:
copy_to_dinode+0x881/0xb30 fs/jfs/jfs_imap.c:3158
diWrite+0x1bf5/0x1f00 fs/jfs/jfs_imap.c:790
txCommit+0xdb8/0x8cd0 fs/jfs/jfs_txnmgr.c:1255
__jfs_xattr_set+0x1b7/0x1f0 fs/jfs/xattr.c:936
jfs_xattr_set+0x79/0x90 fs/jfs/xattr.c:958
__vfs_setxattr+0x844/0x8b0 fs/xattr.c:200
__vfs_setxattr_noperm+0x22f/0xb00 fs/xattr.c:234
__vfs_setxattr_locked+0x441/0x480 fs/xattr.c:295
vfs_setxattr+0x294/0x650 fs/xattr.c:321
do_setxattr fs/xattr.c:629 [inline]
__do_sys_fsetxattr fs/xattr.c:710 [inline]
__se_sys_fsetxattr+0x7f0/0x980 fs/xattr.c:686
__x64_sys_fsetxattr+0xe4/0x150 fs/xattr.c:686
x64_sys_call+0x19c3/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:191
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:
ea_put fs/jfs/xattr.c:639 [inline]
__jfs_setxattr+0x185f/0x1ae0 fs/jfs/xattr.c:785
__jfs_xattr_set+0xe6/0x1f0 fs/jfs/xattr.c:934
jfs_xattr_set+0x79/0x90 fs/jfs/xattr.c:958
__vfs_setxattr+0x844/0x8b0 fs/xattr.c:200
__vfs_setxattr_noperm+0x22f/0xb00 fs/xattr.c:234
__vfs_setxattr_locked+0x441/0x480 fs/xattr.c:295
vfs_setxattr+0x294/0x650 fs/xattr.c:321
do_setxattr fs/xattr.c:629 [inline]
__do_sys_fsetxattr fs/xattr.c:710 [inline]
__se_sys_fsetxattr+0x7f0/0x980 fs/xattr.c:686
__x64_sys_fsetxattr+0xe4/0x150 fs/xattr.c:686
x64_sys_call+0x19c3/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:191
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
Local variable ea_buf created at:
__jfs_setxattr+0x5d/0x1ae0 fs/jfs/xattr.c:662
__jfs_xattr_set+0xe6/0x1f0 fs/jfs/xattr.c:934
CPU: 0 UID: 0 PID: 81 Comm: kswapd0 Tainted: G W 6.11.0-rc5-syzkaller #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
=====================================================
The reason is ea_buf->new_ea is not initialized properly.
Fix this by using memset to empty its content at the begining
in ea_get().
Signed-off-by: Zhao Mengmeng <zhaomengmeng@xxxxxxxxxx>
---
fs/jfs/xattr.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index 2999ed5d83f5..0fb05e314edf 100644
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -434,6 +434,8 @@ static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
int rc;
int quota_allocation = 0;
+ memset(&ea_buf->new_ea, 0, sizeof(ea_buf->new_ea));
+
/* When fsck.jfs clears a bad ea, it doesn't clear the size */
if (ji->ea.flag == 0)
ea_size = 0;
--
2.43.0
