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| author | Zhang Xiaoxu <zhangxiaoxu5@huawei.com> | 2022-05-21 12:08:45 +0800 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2022-05-23 11:06:29 -0400 |
| commit | 6f6f84aa215f7b6665ccbb937db50860f9ec2989 (patch) | |
| tree | e4f849fb15f85c274d3536183099a875b35763e9 /fs/nfsd | |
| parent | 62fdb65edb6c43306c774939001f3a00974832aa (diff) | |
| download | lwn-6f6f84aa215f7b6665ccbb937db50860f9ec2989.tar.gz lwn-6f6f84aa215f7b6665ccbb937db50860f9ec2989.zip | |
nfsd: Fix null-ptr-deref in nfsd_fill_super()
KASAN report null-ptr-deref as follows:
BUG: KASAN: null-ptr-deref in nfsd_fill_super+0xc6/0xe0 [nfsd]
Write of size 8 at addr 000000000000005d by task a.out/852
CPU: 7 PID: 852 Comm: a.out Not tainted 5.18.0-rc7-dirty #66
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x44
kasan_report+0xab/0x120
? nfsd_mkdir+0x71/0x1c0 [nfsd]
? nfsd_fill_super+0xc6/0xe0 [nfsd]
nfsd_fill_super+0xc6/0xe0 [nfsd]
? nfsd_mkdir+0x1c0/0x1c0 [nfsd]
get_tree_keyed+0x8e/0x100
vfs_get_tree+0x41/0xf0
__do_sys_fsconfig+0x590/0x670
? fscontext_read+0x180/0x180
? anon_inode_getfd+0x4f/0x70
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
This can be reproduce by concurrent operations:
1. fsopen(nfsd)/fsconfig
2. insmod/rmmod nfsd
Since the nfsd file system is registered before than nfsd_net allocated,
the caller may get the file_system_type and use the nfsd_net before it
allocated, then null-ptr-deref occurred.
So init_nfsd() should call register_filesystem() last.
Fixes: bd5ae9288d64 ("nfsd: register pernet ops last, unregister first")
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfsd')
| -rw-r--r-- | fs/nfsd/nfsctl.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 55949e60897d..0621c2faf242 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1535,25 +1535,25 @@ static int __init init_nfsd(void) retval = create_proc_exports_entry(); if (retval) goto out_free_lockd; - retval = register_filesystem(&nfsd_fs_type); - if (retval) - goto out_free_exports; retval = register_pernet_subsys(&nfsd_net_ops); if (retval < 0) - goto out_free_filesystem; + goto out_free_exports; retval = register_cld_notifier(); if (retval) goto out_free_subsys; retval = nfsd4_create_laundry_wq(); if (retval) + goto out_free_cld; + retval = register_filesystem(&nfsd_fs_type); + if (retval) goto out_free_all; return 0; out_free_all: + nfsd4_destroy_laundry_wq(); +out_free_cld: unregister_cld_notifier(); out_free_subsys: unregister_pernet_subsys(&nfsd_net_ops); -out_free_filesystem: - unregister_filesystem(&nfsd_fs_type); out_free_exports: remove_proc_entry("fs/nfs/exports", NULL); remove_proc_entry("fs/nfs", NULL); @@ -1571,6 +1571,7 @@ out_free_slabs: static void __exit exit_nfsd(void) { + unregister_filesystem(&nfsd_fs_type); nfsd4_destroy_laundry_wq(); unregister_cld_notifier(); unregister_pernet_subsys(&nfsd_net_ops); @@ -1581,7 +1582,6 @@ static void __exit exit_nfsd(void) nfsd_lockd_shutdown(); nfsd4_free_slabs(); nfsd4_exit_pnfs(); - unregister_filesystem(&nfsd_fs_type); } MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>"); |