From 6a3eb3360667170988f8a6477f6686242061488a Mon Sep 17 00:00:00 2001
From: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Date: Sat, 6 Apr 2019 15:47:38 +0800
Subject: [PATCH 1/5] cifs: Fix use-after-free in SMB2_write
There is a KASAN use-after-free:
BUG: KASAN: use-after-free in SMB2_write+0x1342/0x1580
Read of size 8 at addr ffff8880b6a8e450 by task ln/4196
Should not release the 'req' because it will use in the trace.
Fixes: eccb4422cf97 ("smb3: Add ftrace tracepoints for improved SMB3 debugging")
Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org> 4.18+
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
---
fs/cifs/smb2pdu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 21ad01d55ab2..5d1f8d2d44e4 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3769,7 +3769,6 @@ SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms,
rc = cifs_send_recv(xid, io_parms->tcon->ses, &rqst,
&resp_buftype, flags, &rsp_iov);
- cifs_small_buf_release(req);
rsp = (struct smb2_write_rsp *)rsp_iov.iov_base;
if (rc) {
@@ -3787,6 +3786,7 @@ SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms,
io_parms->offset, *nbytes);
}
+ cifs_small_buf_release(req);
free_rsp_buf(resp_buftype, rsp);
return rc;
}
From 088aaf17aa79300cab14dbee2569c58cfafd7d6e Mon Sep 17 00:00:00 2001
From: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Date: Sat, 6 Apr 2019 15:47:39 +0800
Subject: [PATCH 2/5] cifs: Fix use-after-free in SMB2_read
There is a KASAN use-after-free:
BUG: KASAN: use-after-free in SMB2_read+0x1136/0x1190
Read of size 8 at addr ffff8880b4e45e50 by task ln/1009
Should not release the 'req' because it will use in the trace.
Fixes: eccb4422cf97 ("smb3: Add ftrace tracepoints for improved SMB3 debugging")
Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org> 4.18+
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
---
fs/cifs/smb2pdu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 5d1f8d2d44e4..5d6adc63ad62 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3448,8 +3448,6 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
rqst.rq_nvec = 1;
rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
- cifs_small_buf_release(req);
-
rsp = (struct smb2_read_rsp *)rsp_iov.iov_base;
if (rc) {
@@ -3471,6 +3469,8 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
io_parms->tcon->tid, ses->Suid,
io_parms->offset, io_parms->length);
+ cifs_small_buf_release(req);
+
*nbytes = le32_to_cpu(rsp->DataLength);
if ((*nbytes > CIFS_MAX_MSGSIZE) ||
(*nbytes > io_parms->length)) {
From b57a55e2200ede754e4dc9cce4ba9402544b9365 Mon Sep 17 00:00:00 2001
From: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Date: Sat, 6 Apr 2019 15:30:38 +0800
Subject: [PATCH 3/5] cifs: Fix lease buffer length error
There is a KASAN slab-out-of-bounds:
BUG: KASAN: slab-out-of-bounds in _copy_from_iter_full+0x783/0xaa0
Read of size 80 at addr ffff88810c35e180 by task mount.cifs/539
CPU: 1 PID: 539 Comm: mount.cifs Not tainted 4.19 #10
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack+0xdd/0x12a
print_address_description+0xa7/0x540
kasan_report+0x1ff/0x550
check_memory_region+0x2f1/0x310
memcpy+0x2f/0x80
_copy_from_iter_full+0x783/0xaa0
tcp_sendmsg_locked+0x1840/0x4140
tcp_sendmsg+0x37/0x60
inet_sendmsg+0x18c/0x490
sock_sendmsg+0xae/0x130
smb_send_kvec+0x29c/0x520
__smb_send_rqst+0x3ef/0xc60
smb_send_rqst+0x25a/0x2e0
compound_send_recv+0x9e8/0x2af0
cifs_send_recv+0x24/0x30
SMB2_open+0x35e/0x1620
open_shroot+0x27b/0x490
smb2_open_op_close+0x4e1/0x590
smb2_query_path_info+0x2ac/0x650
cifs_get_inode_info+0x1058/0x28f0
cifs_root_iget+0x3bb/0xf80
cifs_smb3_do_mount+0xe00/0x14c0
cifs_do_mount+0x15/0x20
mount_fs+0x5e/0x290
vfs_kern_mount+0x88/0x460
do_mount+0x398/0x31e0
ksys_mount+0xc6/0x150
__x64_sys_mount+0xea/0x190
do_syscall_64+0x122/0x590
entry_SYSCALL_64_after_hwframe+0x44/0xa9
It can be reproduced by the following step:
1. samba configured with: server max protocol = SMB2_10
2. mount -o vers=default
When parse the mount version parameter, the 'ops' and 'vals'
was setted to smb30, if negotiate result is smb21, just
update the 'ops' to smb21, but the 'vals' is still smb30.
When add lease context, the iov_base is allocated with smb21
ops, but the iov_len is initiallited with the smb30. Because
the iov_len is longer than iov_base, when send the message,
copy array out of bounds.
we need to keep the 'ops' and 'vals' consistent.
Fixes: 9764c02fcbad ("SMB3: Add support for multidialect negotiate (SMB2.1 and later)")
Fixes: d5c7076b772a ("smb3: add smb3.1.1 to default dialect list")
Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
---
fs/cifs/smb2pdu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 5d6adc63ad62..b8f7262ac354 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -832,8 +832,11 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
} else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
/* ops set to 3.0 by default for default so update */
ses->server->ops = &smb21_operations;
- } else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID))
+ ses->server->vals = &smb21_values;
+ } else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
ses->server->ops = &smb311_operations;
+ ses->server->vals = &smb311_values;
+ }
} else if (le16_to_cpu(rsp->DialectRevision) !=
ses->server->vals->protocol_id) {
/* if requested single dialect ensure returned dialect matched */
From e6d0fb7b34f264f72c33053558a360a6a734905e Mon Sep 17 00:00:00 2001
From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Wed, 10 Apr 2019 07:47:22 +1000
Subject: [PATCH 4/5] cifs: fix handle leak in smb2_query_symlink()
If we enter smb2_query_symlink() for something that is not a symlink
and where the SMB2_open() would succeed we would never end up
closing this handle and would thus leak a handle on the server.
Fix this by immediately calling SMB2_close() on successfull open.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
---
fs/cifs/smb2ops.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 00225e699d03..c36ff0d1fe2a 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2389,6 +2389,8 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, &err_iov,
&resp_buftype);
+ if (!rc)
+ SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
if (!rc || !err_iov.iov_base) {
rc = -ENOENT;
goto free_path;
From b98749cac4a695f084a5ff076f4510b23e353ecd Mon Sep 17 00:00:00 2001
From: Aurelien Aptel <aaptel@suse.com>
Date: Fri, 29 Mar 2019 10:49:12 +0100
Subject: [PATCH 5/5] CIFS: keep FileInfo handle live during oplock break
In the oplock break handler, writing pending changes from pages puts
the FileInfo handle. If the refcount reaches zero it closes the handle
and waits for any oplock break handler to return, thus causing a deadlock.
To prevent this situation:
* We add a wait flag to cifsFileInfo_put() to decide whether we should
wait for running/pending oplock break handlers
* We keep an additionnal reference of the SMB FileInfo handle so that
for the rest of the handler putting the handle won't close it.
- The ref is bumped everytime we queue the handler via the
cifs_queue_oplock_break() helper.
- The ref is decremented at the end of the handler
This bug was triggered by xfstest 464.
Also important fix to address the various reports of
oops in smb2_push_mandatory_locks
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
---
fs/cifs/cifsglob.h | 2 ++
fs/cifs/file.c | 30 +++++++++++++++++++++++++-----
fs/cifs/misc.c | 25 +++++++++++++++++++++++--
fs/cifs/smb2misc.c | 6 +++---
4 files changed, 53 insertions(+), 10 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 5b18d4585740..585ad3207cb1 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1333,6 +1333,7 @@ cifsFileInfo_get_locked(struct cifsFileInfo *cifs_file)
}
struct cifsFileInfo *cifsFileInfo_get(struct cifsFileInfo *cifs_file);
+void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_hdlr);
void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
#define CIFS_CACHE_READ_FLG 1
@@ -1855,6 +1856,7 @@ GLOBAL_EXTERN spinlock_t gidsidlock;
#endif /* CONFIG_CIFS_ACL */
void cifs_oplock_break(struct work_struct *work);
+void cifs_queue_oplock_break(struct cifsFileInfo *cfile);
extern const struct slow_work_ops cifs_oplock_break_ops;
extern struct workqueue_struct *cifsiod_wq;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 89006e044973..9c0ccc06d172 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -360,12 +360,30 @@ cifsFileInfo_get(struct cifsFileInfo *cifs_file)
return cifs_file;
}
-/*
- * Release a reference on the file private data. This may involve closing
- * the filehandle out on the server. Must be called without holding
- * tcon->open_file_lock and cifs_file->file_info_lock.
+/**
+ * cifsFileInfo_put - release a reference of file priv data
+ *
+ * Always potentially wait for oplock handler. See _cifsFileInfo_put().
*/
void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
+{
+ _cifsFileInfo_put(cifs_file, true);
+}
+
+/**
+ * _cifsFileInfo_put - release a reference of file priv data
+ *
+ * This may involve closing the filehandle @cifs_file out on the
+ * server. Must be called without holding tcon->open_file_lock and
+ * cifs_file->file_info_lock.
+ *
+ * If @wait_for_oplock_handler is true and we are releasing the last
+ * reference, wait for any running oplock break handler of the file
+ * and cancel any pending one. If calling this function from the
+ * oplock break handler, you need to pass false.
+ *
+ */
+void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
{
struct inode *inode = d_inode(cifs_file->dentry);
struct cifs_tcon *tcon = tlink_tcon(cifs_file->tlink);
@@ -414,7 +432,8 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
spin_unlock(&tcon->open_file_lock);
- oplock_break_cancelled = cancel_work_sync(&cifs_file->oplock_break);
+ oplock_break_cancelled = wait_oplock_handler ?
+ cancel_work_sync(&cifs_file->oplock_break) : false;
if (!tcon->need_reconnect && !cifs_file->invalidHandle) {
struct TCP_Server_Info *server = tcon->ses->server;
@@ -4603,6 +4622,7 @@ void cifs_oplock_break(struct work_struct *work)
cinode);
cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
}
+ _cifsFileInfo_put(cfile, false /* do not wait for ourself */);
cifs_done_oplock_break(cinode);
}
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index bee203055b30..1e1626a2cfc3 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -501,8 +501,7 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
&pCifsInode->flags);
- queue_work(cifsoplockd_wq,
- &netfile->oplock_break);
+ cifs_queue_oplock_break(netfile);
netfile->oplock_break_cancelled = false;
spin_unlock(&tcon->open_file_lock);
@@ -607,6 +606,28 @@ void cifs_put_writer(struct cifsInodeInfo *cinode)
spin_unlock(&cinode->writers_lock);
}
+/**
+ * cifs_queue_oplock_break - queue the oplock break handler for cfile
+ *
+ * This function is called from the demultiplex thread when it
+ * receives an oplock break for @cfile.
+ *
+ * Assumes the tcon->open_file_lock is held.
+ * Assumes cfile->file_info_lock is NOT held.
+ */
+void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
+{
+ /*
+ * Bump the handle refcount now while we hold the
+ * open_file_lock to enforce the validity of it for the oplock
+ * break handler. The matching put is done at the end of the
+ * handler.
+ */
+ cifsFileInfo_get(cfile);
+
+ queue_work(cifsoplockd_wq, &cfile->oplock_break);
+}
+
void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
{
clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 0e3570e40ff8..e311f58dc1c8 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -555,7 +555,7 @@ smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
clear_bit(CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
&cinode->flags);
- queue_work(cifsoplockd_wq, &cfile->oplock_break);
+ cifs_queue_oplock_break(cfile);
kfree(lw);
return true;
}
@@ -712,8 +712,8 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
&cinode->flags);
spin_unlock(&cfile->file_info_lock);
- queue_work(cifsoplockd_wq,
- &cfile->oplock_break);
+
+ cifs_queue_oplock_break(cfile);
spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);