From: Zhongqiu Han quic_zhonhan@quicinc.com
[ Upstream commit 9629d7d66c621671d9a47afe27ca9336bfc8a9ea ]
syzbot reports that hex_dump_to_buffer is using uninit-value:
===================================================== BUG: KMSAN: uninit-value in hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171 hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171 print_hex_dump+0x13d/0x3e0 lib/hexdump.c:276 diFree+0x5ba/0x4350 fs/jfs/jfs_imap.c:876 jfs_evict_inode+0x510/0x550 fs/jfs/inode.c:156 evict+0x723/0xd10 fs/inode.c:796 iput_final fs/inode.c:1946 [inline] iput+0x97b/0xdb0 fs/inode.c:1972 txUpdateMap+0xf3e/0x1150 fs/jfs/jfs_txnmgr.c:2367 txLazyCommit fs/jfs/jfs_txnmgr.c:2664 [inline] jfs_lazycommit+0x627/0x11d0 fs/jfs/jfs_txnmgr.c:2733 kthread+0x6b9/0xef0 kernel/kthread.c:464 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Uninit was created at: slab_post_alloc_hook mm/slub.c:4121 [inline] slab_alloc_node mm/slub.c:4164 [inline] __kmalloc_cache_noprof+0x8e3/0xdf0 mm/slub.c:4320 kmalloc_noprof include/linux/slab.h:901 [inline] diMount+0x61/0x7f0 fs/jfs/jfs_imap.c:105 jfs_mount+0xa8e/0x11d0 fs/jfs/jfs_mount.c:176 jfs_fill_super+0xa47/0x17c0 fs/jfs/super.c:523 get_tree_bdev_flags+0x6ec/0x910 fs/super.c:1636 get_tree_bdev+0x37/0x50 fs/super.c:1659 jfs_get_tree+0x34/0x40 fs/jfs/super.c:635 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814 do_new_mount+0x71f/0x15e0 fs/namespace.c:3560 path_mount+0x742/0x1f10 fs/namespace.c:3887 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x71f/0x800 fs/namespace.c:4088 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4088 x64_sys_call+0x39bf/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:166 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 =====================================================
The reason is that imap is not properly initialized after memory allocation. It will cause the snprintf() function to write uninitialized data into linebuf within hex_dump_to_buffer().
Fix this by using kzalloc instead of kmalloc to clear its content at the beginning in diMount().
Signed-off-by: Zhongqiu Han quic_zhonhan@quicinc.com Reported-by: syzbot+df6cdcb35904203d2b6d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/lkml/67b5d07e.050a0220.14d86d.00e6.GAE@google.com/ Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/jfs/jfs_imap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c index c72e97f065798..309b5f6e977d7 100644 --- a/fs/jfs/jfs_imap.c +++ b/fs/jfs/jfs_imap.c @@ -102,7 +102,7 @@ int diMount(struct inode *ipimap) * allocate/initialize the in-memory inode map control structure */ /* allocate the in-memory inode map control structure. */ - imap = kmalloc(sizeof(struct inomap), GFP_KERNEL); + imap = kzalloc(sizeof(struct inomap), GFP_KERNEL); if (imap == NULL) return -ENOMEM;