* FAILED: patch "[PATCH] ksmbd: validate owner of durable handle on reconnect" failed to apply to 7.0-stable tree
@ 2026-04-20 14:55 gregkh
2026-04-20 16:15 ` [PATCH 7.0.y 1/2] ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2026-04-20 14:55 UTC (permalink / raw)
To: linkinjeon, d.ornaghi97, knavaneeth786, stfrench; +Cc: stable
The patch below does not apply to the 7.0-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-7.0.y
git checkout FETCH_HEAD
git cherry-pick -x 49110a8ce654bbe56bef7c5e44cce31f4b102b8a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026042008-renovate-washout-9325@gregkh' --subject-prefix 'PATCH 7.0.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 49110a8ce654bbe56bef7c5e44cce31f4b102b8a Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@kernel.org>
Date: Sun, 12 Apr 2026 22:16:16 +0900
Subject: [PATCH] ksmbd: validate owner of durable handle on reconnect
Currently, ksmbd does not verify if the user attempting to reconnect
to a durable handle is the same user who originally opened the file.
This allows any authenticated user to hijack an orphaned durable handle
by predicting or brute-forcing the persistent ID.
According to MS-SMB2, the server MUST verify that the SecurityContext
of the reconnect request matches the SecurityContext associated with
the existing open.
Add a durable_owner structure to ksmbd_file to store the original opener's
UID, GID, and account name. and catpure the owner information when a file
handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner()
to validate the identity of the requester during SMB2_CREATE (DHnC).
Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2")
Reported-by: Davide Ornaghi <d.ornaghi97@gmail.com>
Reported-by: Navaneeth K <knavaneeth786@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/smb/server/mgmt/user_session.c b/fs/smb/server/mgmt/user_session.c
index 39be2d2be86c..a86589408835 100644
--- a/fs/smb/server/mgmt/user_session.c
+++ b/fs/smb/server/mgmt/user_session.c
@@ -382,12 +382,10 @@ void ksmbd_session_destroy(struct ksmbd_session *sess)
return;
delete_proc_session(sess);
-
+ ksmbd_tree_conn_session_logoff(sess);
+ ksmbd_destroy_file_table(sess);
if (sess->user)
ksmbd_free_user(sess->user);
-
- ksmbd_tree_conn_session_logoff(sess);
- ksmbd_destroy_file_table(&sess->file_table);
ksmbd_launch_ksmbd_durable_scavenger();
ksmbd_session_rpc_clear_list(sess);
free_channel_list(sess);
@@ -618,7 +616,7 @@ void destroy_previous_session(struct ksmbd_conn *conn,
goto out;
}
- ksmbd_destroy_file_table(&prev_sess->file_table);
+ ksmbd_destroy_file_table(prev_sess);
prev_sess->state = SMB2_SESSION_EXPIRED;
ksmbd_all_conn_set_status(id, KSMBD_SESS_NEED_SETUP);
ksmbd_launch_ksmbd_durable_scavenger();
diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
index 9b2bb8764a80..cd3f28b0e7cb 100644
--- a/fs/smb/server/oplock.c
+++ b/fs/smb/server/oplock.c
@@ -1841,6 +1841,7 @@ int smb2_check_durable_oplock(struct ksmbd_conn *conn,
struct ksmbd_share_config *share,
struct ksmbd_file *fp,
struct lease_ctx_info *lctx,
+ struct ksmbd_user *user,
char *name)
{
struct oplock_info *opinfo = opinfo_get(fp);
@@ -1849,6 +1850,12 @@ int smb2_check_durable_oplock(struct ksmbd_conn *conn,
if (!opinfo)
return 0;
+ if (ksmbd_vfs_compare_durable_owner(fp, user) == false) {
+ ksmbd_debug(SMB, "Durable handle reconnect failed: owner mismatch\n");
+ ret = -EBADF;
+ goto out;
+ }
+
if (opinfo->is_lease == false) {
if (lctx) {
pr_err("create context include lease\n");
diff --git a/fs/smb/server/oplock.h b/fs/smb/server/oplock.h
index 921e3199e4df..d91a8266e065 100644
--- a/fs/smb/server/oplock.h
+++ b/fs/smb/server/oplock.h
@@ -126,5 +126,6 @@ int smb2_check_durable_oplock(struct ksmbd_conn *conn,
struct ksmbd_share_config *share,
struct ksmbd_file *fp,
struct lease_ctx_info *lctx,
+ struct ksmbd_user *user,
char *name);
#endif /* __KSMBD_OPLOCK_H */
diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 764a78dec46a..d0b05878757e 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -3013,7 +3013,8 @@ int smb2_open(struct ksmbd_work *work)
}
if (dh_info.reconnected == true) {
- rc = smb2_check_durable_oplock(conn, share, dh_info.fp, lc, name);
+ rc = smb2_check_durable_oplock(conn, share, dh_info.fp,
+ lc, sess->user, name);
if (rc) {
ksmbd_put_durable_fd(dh_info.fp);
goto err_out2;
diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index 87f63525062b..3551f01a3fa0 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -19,6 +19,7 @@
#include "misc.h"
#include "mgmt/tree_connect.h"
#include "mgmt/user_session.h"
+#include "mgmt/user_config.h"
#include "smb_common.h"
#include "server.h"
#include "smb2pdu.h"
@@ -476,6 +477,8 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp)
if (ksmbd_stream_fd(fp))
kfree(fp->stream.name);
+ kfree(fp->owner.name);
+
kmem_cache_free(filp_cache, fp);
}
@@ -787,11 +790,13 @@ void ksmbd_update_fstate(struct ksmbd_file_table *ft, struct ksmbd_file *fp,
}
static int
-__close_file_table_ids(struct ksmbd_file_table *ft,
+__close_file_table_ids(struct ksmbd_session *sess,
struct ksmbd_tree_connect *tcon,
bool (*skip)(struct ksmbd_tree_connect *tcon,
- struct ksmbd_file *fp))
+ struct ksmbd_file *fp,
+ struct ksmbd_user *user))
{
+ struct ksmbd_file_table *ft = &sess->file_table;
struct ksmbd_file *fp;
unsigned int id = 0;
int num = 0;
@@ -804,7 +809,7 @@ __close_file_table_ids(struct ksmbd_file_table *ft,
break;
}
- if (skip(tcon, fp) ||
+ if (skip(tcon, fp, sess->user) ||
!atomic_dec_and_test(&fp->refcount)) {
id++;
write_unlock(&ft->lock);
@@ -856,7 +861,8 @@ static inline bool is_reconnectable(struct ksmbd_file *fp)
}
static bool tree_conn_fd_check(struct ksmbd_tree_connect *tcon,
- struct ksmbd_file *fp)
+ struct ksmbd_file *fp,
+ struct ksmbd_user *user)
{
return fp->tcon != tcon;
}
@@ -991,8 +997,62 @@ void ksmbd_stop_durable_scavenger(void)
kthread_stop(server_conf.dh_task);
}
+/*
+ * ksmbd_vfs_copy_durable_owner - Copy owner info for durable reconnect
+ * @fp: ksmbd file pointer to store owner info
+ * @user: user pointer to copy from
+ *
+ * This function binds the current user's identity to the file handle
+ * to satisfy MS-SMB2 Step 8 (SecurityContext matching) during reconnect.
+ *
+ * Return: 0 on success, or negative error code on failure
+ */
+static int ksmbd_vfs_copy_durable_owner(struct ksmbd_file *fp,
+ struct ksmbd_user *user)
+{
+ if (!user)
+ return -EINVAL;
+
+ /* Duplicate the user name to ensure identity persistence */
+ fp->owner.name = kstrdup(user->name, GFP_KERNEL);
+ if (!fp->owner.name)
+ return -ENOMEM;
+
+ fp->owner.uid = user->uid;
+ fp->owner.gid = user->gid;
+
+ return 0;
+}
+
+/**
+ * ksmbd_vfs_compare_durable_owner - Verify if the requester is original owner
+ * @fp: existing ksmbd file pointer
+ * @user: user pointer of the reconnect requester
+ *
+ * Compares the UID, GID, and name of the current requester against the
+ * original owner stored in the file handle.
+ *
+ * Return: true if the user matches, false otherwise
+ */
+bool ksmbd_vfs_compare_durable_owner(struct ksmbd_file *fp,
+ struct ksmbd_user *user)
+{
+ if (!user || !fp->owner.name)
+ return false;
+
+ /* Check if the UID and GID match first (fast path) */
+ if (fp->owner.uid != user->uid || fp->owner.gid != user->gid)
+ return false;
+
+ /* Validate the account name to ensure the same SecurityContext */
+ if (strcmp(fp->owner.name, user->name))
+ return false;
+
+ return true;
+}
+
static bool session_fd_check(struct ksmbd_tree_connect *tcon,
- struct ksmbd_file *fp)
+ struct ksmbd_file *fp, struct ksmbd_user *user)
{
struct ksmbd_inode *ci;
struct oplock_info *op;
@@ -1002,6 +1062,9 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
if (!is_reconnectable(fp))
return false;
+ if (ksmbd_vfs_copy_durable_owner(fp, user))
+ return false;
+
conn = fp->conn;
ci = fp->f_ci;
down_write(&ci->m_lock);
@@ -1033,7 +1096,7 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
void ksmbd_close_tree_conn_fds(struct ksmbd_work *work)
{
- int num = __close_file_table_ids(&work->sess->file_table,
+ int num = __close_file_table_ids(work->sess,
work->tcon,
tree_conn_fd_check);
@@ -1042,7 +1105,7 @@ void ksmbd_close_tree_conn_fds(struct ksmbd_work *work)
void ksmbd_close_session_fds(struct ksmbd_work *work)
{
- int num = __close_file_table_ids(&work->sess->file_table,
+ int num = __close_file_table_ids(work->sess,
work->tcon,
session_fd_check);
@@ -1140,6 +1203,10 @@ int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp)
}
up_write(&ci->m_lock);
+ fp->owner.uid = fp->owner.gid = 0;
+ kfree(fp->owner.name);
+ fp->owner.name = NULL;
+
return 0;
}
@@ -1154,12 +1221,14 @@ int ksmbd_init_file_table(struct ksmbd_file_table *ft)
return 0;
}
-void ksmbd_destroy_file_table(struct ksmbd_file_table *ft)
+void ksmbd_destroy_file_table(struct ksmbd_session *sess)
{
+ struct ksmbd_file_table *ft = &sess->file_table;
+
if (!ft->idr)
return;
- __close_file_table_ids(ft, NULL, session_fd_check);
+ __close_file_table_ids(sess, NULL, session_fd_check);
idr_destroy(ft->idr);
kfree(ft->idr);
ft->idr = NULL;
diff --git a/fs/smb/server/vfs_cache.h b/fs/smb/server/vfs_cache.h
index 78b506c5ef03..866f32c10d4d 100644
--- a/fs/smb/server/vfs_cache.h
+++ b/fs/smb/server/vfs_cache.h
@@ -68,6 +68,13 @@ enum {
FP_CLOSED
};
+/* Owner information for durable handle reconnect */
+struct durable_owner {
+ unsigned int uid;
+ unsigned int gid;
+ char *name;
+};
+
struct ksmbd_file {
struct file *filp;
u64 persistent_id;
@@ -114,6 +121,7 @@ struct ksmbd_file {
bool is_resilient;
bool is_posix_ctxt;
+ struct durable_owner owner;
};
static inline void set_ctx_actor(struct dir_context *ctx,
@@ -140,7 +148,7 @@ static inline bool ksmbd_stream_fd(struct ksmbd_file *fp)
}
int ksmbd_init_file_table(struct ksmbd_file_table *ft);
-void ksmbd_destroy_file_table(struct ksmbd_file_table *ft);
+void ksmbd_destroy_file_table(struct ksmbd_session *sess);
int ksmbd_close_fd(struct ksmbd_work *work, u64 id);
struct ksmbd_file *ksmbd_lookup_fd_fast(struct ksmbd_work *work, u64 id);
struct ksmbd_file *ksmbd_lookup_foreign_fd(struct ksmbd_work *work, u64 id);
@@ -166,6 +174,8 @@ void ksmbd_free_global_file_table(void);
void ksmbd_set_fd_limit(unsigned long limit);
void ksmbd_update_fstate(struct ksmbd_file_table *ft, struct ksmbd_file *fp,
unsigned int state);
+bool ksmbd_vfs_compare_durable_owner(struct ksmbd_file *fp,
+ struct ksmbd_user *user);
/*
* INODE hash
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 7.0.y 1/2] ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger
2026-04-20 14:55 FAILED: patch "[PATCH] ksmbd: validate owner of durable handle on reconnect" failed to apply to 7.0-stable tree gregkh
@ 2026-04-20 16:15 ` Sasha Levin
2026-04-20 16:15 ` [PATCH 7.0.y 2/2] ksmbd: validate owner of durable handle on reconnect Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: Sasha Levin @ 2026-04-20 16:15 UTC (permalink / raw)
To: stable; +Cc: Namjae Jeon, munan Huang, ChenXiaoSong, Steve French, Sasha Levin
From: Namjae Jeon <linkinjeon@kernel.org>
[ Upstream commit 235e32320a470fcd3998fb3774f2290a0eb302a1 ]
When a durable file handle survives session disconnect (TCP close without
SMB2_LOGOFF), session_fd_check() sets fp->conn = NULL to preserve the
handle for later reconnection. However, it did not clean up the byte-range
locks on fp->lock_list.
Later, when the durable scavenger thread times out and calls
__ksmbd_close_fd(NULL, fp), the lock cleanup loop did:
spin_lock(&fp->conn->llist_lock);
This caused a slab use-after-free because fp->conn was NULL and the
original connection object had already been freed by
ksmbd_tcp_disconnect().
The root cause is asymmetric cleanup: lock entries (smb_lock->clist) were
left dangling on the freed conn->lock_list while fp->conn was nulled out.
To fix this issue properly, we need to handle the lifetime of
smb_lock->clist across three paths:
- Safely skip clist deletion when list is empty and fp->conn is NULL.
- Remove the lock from the old connection's lock_list in
session_fd_check()
- Re-add the lock to the new connection's lock_list in
ksmbd_reopen_durable_fd().
Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2")
Co-developed-by: munan Huang <munanevil@gmail.com>
Signed-off-by: munan Huang <munanevil@gmail.com>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: 49110a8ce654 ("ksmbd: validate owner of durable handle on reconnect")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/smb/server/vfs_cache.c | 41 ++++++++++++++++++++++++++++-----------
1 file changed, 30 insertions(+), 11 deletions(-)
diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index 168f2dd7e200b..87f63525062b1 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -463,9 +463,11 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp)
* there are not accesses to fp->lock_list.
*/
list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) {
- spin_lock(&fp->conn->llist_lock);
- list_del(&smb_lock->clist);
- spin_unlock(&fp->conn->llist_lock);
+ if (!list_empty(&smb_lock->clist) && fp->conn) {
+ spin_lock(&fp->conn->llist_lock);
+ list_del(&smb_lock->clist);
+ spin_unlock(&fp->conn->llist_lock);
+ }
list_del(&smb_lock->flist);
locks_free_lock(smb_lock->fl);
@@ -995,6 +997,7 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
struct ksmbd_inode *ci;
struct oplock_info *op;
struct ksmbd_conn *conn;
+ struct ksmbd_lock *smb_lock, *tmp_lock;
if (!is_reconnectable(fp))
return false;
@@ -1011,6 +1014,12 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
}
up_write(&ci->m_lock);
+ list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) {
+ spin_lock(&fp->conn->llist_lock);
+ list_del_init(&smb_lock->clist);
+ spin_unlock(&fp->conn->llist_lock);
+ }
+
fp->conn = NULL;
fp->tcon = NULL;
fp->volatile_id = KSMBD_NO_FID;
@@ -1090,6 +1099,9 @@ int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp)
{
struct ksmbd_inode *ci;
struct oplock_info *op;
+ struct ksmbd_conn *conn = work->conn;
+ struct ksmbd_lock *smb_lock;
+ unsigned int old_f_state;
if (!fp->is_durable || fp->conn || fp->tcon) {
pr_err("Invalid durable fd [%p:%p]\n", fp->conn, fp->tcon);
@@ -1101,9 +1113,23 @@ int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp)
return -EBADF;
}
- fp->conn = work->conn;
+ old_f_state = fp->f_state;
+ fp->f_state = FP_NEW;
+ __open_id(&work->sess->file_table, fp, OPEN_ID_TYPE_VOLATILE_ID);
+ if (!has_file_id(fp->volatile_id)) {
+ fp->f_state = old_f_state;
+ return -EBADF;
+ }
+
+ fp->conn = conn;
fp->tcon = work->tcon;
+ list_for_each_entry(smb_lock, &fp->lock_list, flist) {
+ spin_lock(&conn->llist_lock);
+ list_add_tail(&smb_lock->clist, &conn->lock_list);
+ spin_unlock(&conn->llist_lock);
+ }
+
ci = fp->f_ci;
down_write(&ci->m_lock);
list_for_each_entry_rcu(op, &ci->m_op_list, op_entry) {
@@ -1114,13 +1140,6 @@ int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp)
}
up_write(&ci->m_lock);
- fp->f_state = FP_NEW;
- __open_id(&work->sess->file_table, fp, OPEN_ID_TYPE_VOLATILE_ID);
- if (!has_file_id(fp->volatile_id)) {
- fp->conn = NULL;
- fp->tcon = NULL;
- return -EBADF;
- }
return 0;
}
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 7.0.y 2/2] ksmbd: validate owner of durable handle on reconnect
2026-04-20 16:15 ` [PATCH 7.0.y 1/2] ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger Sasha Levin
@ 2026-04-20 16:15 ` Sasha Levin
0 siblings, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2026-04-20 16:15 UTC (permalink / raw)
To: stable; +Cc: Namjae Jeon, Davide Ornaghi, Navaneeth K, Steve French,
Sasha Levin
From: Namjae Jeon <linkinjeon@kernel.org>
[ Upstream commit 49110a8ce654bbe56bef7c5e44cce31f4b102b8a ]
Currently, ksmbd does not verify if the user attempting to reconnect
to a durable handle is the same user who originally opened the file.
This allows any authenticated user to hijack an orphaned durable handle
by predicting or brute-forcing the persistent ID.
According to MS-SMB2, the server MUST verify that the SecurityContext
of the reconnect request matches the SecurityContext associated with
the existing open.
Add a durable_owner structure to ksmbd_file to store the original opener's
UID, GID, and account name. and catpure the owner information when a file
handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner()
to validate the identity of the requester during SMB2_CREATE (DHnC).
Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2")
Reported-by: Davide Ornaghi <d.ornaghi97@gmail.com>
Reported-by: Navaneeth K <knavaneeth786@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/smb/server/mgmt/user_session.c | 8 ++-
fs/smb/server/oplock.c | 7 +++
fs/smb/server/oplock.h | 1 +
fs/smb/server/smb2pdu.c | 3 +-
fs/smb/server/vfs_cache.c | 87 +++++++++++++++++++++++++++----
fs/smb/server/vfs_cache.h | 12 ++++-
6 files changed, 102 insertions(+), 16 deletions(-)
diff --git a/fs/smb/server/mgmt/user_session.c b/fs/smb/server/mgmt/user_session.c
index 39be2d2be86c3..a86589408835b 100644
--- a/fs/smb/server/mgmt/user_session.c
+++ b/fs/smb/server/mgmt/user_session.c
@@ -382,12 +382,10 @@ void ksmbd_session_destroy(struct ksmbd_session *sess)
return;
delete_proc_session(sess);
-
+ ksmbd_tree_conn_session_logoff(sess);
+ ksmbd_destroy_file_table(sess);
if (sess->user)
ksmbd_free_user(sess->user);
-
- ksmbd_tree_conn_session_logoff(sess);
- ksmbd_destroy_file_table(&sess->file_table);
ksmbd_launch_ksmbd_durable_scavenger();
ksmbd_session_rpc_clear_list(sess);
free_channel_list(sess);
@@ -618,7 +616,7 @@ void destroy_previous_session(struct ksmbd_conn *conn,
goto out;
}
- ksmbd_destroy_file_table(&prev_sess->file_table);
+ ksmbd_destroy_file_table(prev_sess);
prev_sess->state = SMB2_SESSION_EXPIRED;
ksmbd_all_conn_set_status(id, KSMBD_SESS_NEED_SETUP);
ksmbd_launch_ksmbd_durable_scavenger();
diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
index 9b2bb8764a805..cd3f28b0e7cb2 100644
--- a/fs/smb/server/oplock.c
+++ b/fs/smb/server/oplock.c
@@ -1841,6 +1841,7 @@ int smb2_check_durable_oplock(struct ksmbd_conn *conn,
struct ksmbd_share_config *share,
struct ksmbd_file *fp,
struct lease_ctx_info *lctx,
+ struct ksmbd_user *user,
char *name)
{
struct oplock_info *opinfo = opinfo_get(fp);
@@ -1849,6 +1850,12 @@ int smb2_check_durable_oplock(struct ksmbd_conn *conn,
if (!opinfo)
return 0;
+ if (ksmbd_vfs_compare_durable_owner(fp, user) == false) {
+ ksmbd_debug(SMB, "Durable handle reconnect failed: owner mismatch\n");
+ ret = -EBADF;
+ goto out;
+ }
+
if (opinfo->is_lease == false) {
if (lctx) {
pr_err("create context include lease\n");
diff --git a/fs/smb/server/oplock.h b/fs/smb/server/oplock.h
index 921e3199e4df4..d91a8266e065e 100644
--- a/fs/smb/server/oplock.h
+++ b/fs/smb/server/oplock.h
@@ -126,5 +126,6 @@ int smb2_check_durable_oplock(struct ksmbd_conn *conn,
struct ksmbd_share_config *share,
struct ksmbd_file *fp,
struct lease_ctx_info *lctx,
+ struct ksmbd_user *user,
char *name);
#endif /* __KSMBD_OPLOCK_H */
diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 8e4cfdc0ba025..bfa542e6af999 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -3013,7 +3013,8 @@ int smb2_open(struct ksmbd_work *work)
}
if (dh_info.reconnected == true) {
- rc = smb2_check_durable_oplock(conn, share, dh_info.fp, lc, name);
+ rc = smb2_check_durable_oplock(conn, share, dh_info.fp,
+ lc, sess->user, name);
if (rc) {
ksmbd_put_durable_fd(dh_info.fp);
goto err_out2;
diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index 87f63525062b1..3551f01a3fa03 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -19,6 +19,7 @@
#include "misc.h"
#include "mgmt/tree_connect.h"
#include "mgmt/user_session.h"
+#include "mgmt/user_config.h"
#include "smb_common.h"
#include "server.h"
#include "smb2pdu.h"
@@ -476,6 +477,8 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp)
if (ksmbd_stream_fd(fp))
kfree(fp->stream.name);
+ kfree(fp->owner.name);
+
kmem_cache_free(filp_cache, fp);
}
@@ -787,11 +790,13 @@ void ksmbd_update_fstate(struct ksmbd_file_table *ft, struct ksmbd_file *fp,
}
static int
-__close_file_table_ids(struct ksmbd_file_table *ft,
+__close_file_table_ids(struct ksmbd_session *sess,
struct ksmbd_tree_connect *tcon,
bool (*skip)(struct ksmbd_tree_connect *tcon,
- struct ksmbd_file *fp))
+ struct ksmbd_file *fp,
+ struct ksmbd_user *user))
{
+ struct ksmbd_file_table *ft = &sess->file_table;
struct ksmbd_file *fp;
unsigned int id = 0;
int num = 0;
@@ -804,7 +809,7 @@ __close_file_table_ids(struct ksmbd_file_table *ft,
break;
}
- if (skip(tcon, fp) ||
+ if (skip(tcon, fp, sess->user) ||
!atomic_dec_and_test(&fp->refcount)) {
id++;
write_unlock(&ft->lock);
@@ -856,7 +861,8 @@ static inline bool is_reconnectable(struct ksmbd_file *fp)
}
static bool tree_conn_fd_check(struct ksmbd_tree_connect *tcon,
- struct ksmbd_file *fp)
+ struct ksmbd_file *fp,
+ struct ksmbd_user *user)
{
return fp->tcon != tcon;
}
@@ -991,8 +997,62 @@ void ksmbd_stop_durable_scavenger(void)
kthread_stop(server_conf.dh_task);
}
+/*
+ * ksmbd_vfs_copy_durable_owner - Copy owner info for durable reconnect
+ * @fp: ksmbd file pointer to store owner info
+ * @user: user pointer to copy from
+ *
+ * This function binds the current user's identity to the file handle
+ * to satisfy MS-SMB2 Step 8 (SecurityContext matching) during reconnect.
+ *
+ * Return: 0 on success, or negative error code on failure
+ */
+static int ksmbd_vfs_copy_durable_owner(struct ksmbd_file *fp,
+ struct ksmbd_user *user)
+{
+ if (!user)
+ return -EINVAL;
+
+ /* Duplicate the user name to ensure identity persistence */
+ fp->owner.name = kstrdup(user->name, GFP_KERNEL);
+ if (!fp->owner.name)
+ return -ENOMEM;
+
+ fp->owner.uid = user->uid;
+ fp->owner.gid = user->gid;
+
+ return 0;
+}
+
+/**
+ * ksmbd_vfs_compare_durable_owner - Verify if the requester is original owner
+ * @fp: existing ksmbd file pointer
+ * @user: user pointer of the reconnect requester
+ *
+ * Compares the UID, GID, and name of the current requester against the
+ * original owner stored in the file handle.
+ *
+ * Return: true if the user matches, false otherwise
+ */
+bool ksmbd_vfs_compare_durable_owner(struct ksmbd_file *fp,
+ struct ksmbd_user *user)
+{
+ if (!user || !fp->owner.name)
+ return false;
+
+ /* Check if the UID and GID match first (fast path) */
+ if (fp->owner.uid != user->uid || fp->owner.gid != user->gid)
+ return false;
+
+ /* Validate the account name to ensure the same SecurityContext */
+ if (strcmp(fp->owner.name, user->name))
+ return false;
+
+ return true;
+}
+
static bool session_fd_check(struct ksmbd_tree_connect *tcon,
- struct ksmbd_file *fp)
+ struct ksmbd_file *fp, struct ksmbd_user *user)
{
struct ksmbd_inode *ci;
struct oplock_info *op;
@@ -1002,6 +1062,9 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
if (!is_reconnectable(fp))
return false;
+ if (ksmbd_vfs_copy_durable_owner(fp, user))
+ return false;
+
conn = fp->conn;
ci = fp->f_ci;
down_write(&ci->m_lock);
@@ -1033,7 +1096,7 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
void ksmbd_close_tree_conn_fds(struct ksmbd_work *work)
{
- int num = __close_file_table_ids(&work->sess->file_table,
+ int num = __close_file_table_ids(work->sess,
work->tcon,
tree_conn_fd_check);
@@ -1042,7 +1105,7 @@ void ksmbd_close_tree_conn_fds(struct ksmbd_work *work)
void ksmbd_close_session_fds(struct ksmbd_work *work)
{
- int num = __close_file_table_ids(&work->sess->file_table,
+ int num = __close_file_table_ids(work->sess,
work->tcon,
session_fd_check);
@@ -1140,6 +1203,10 @@ int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp)
}
up_write(&ci->m_lock);
+ fp->owner.uid = fp->owner.gid = 0;
+ kfree(fp->owner.name);
+ fp->owner.name = NULL;
+
return 0;
}
@@ -1154,12 +1221,14 @@ int ksmbd_init_file_table(struct ksmbd_file_table *ft)
return 0;
}
-void ksmbd_destroy_file_table(struct ksmbd_file_table *ft)
+void ksmbd_destroy_file_table(struct ksmbd_session *sess)
{
+ struct ksmbd_file_table *ft = &sess->file_table;
+
if (!ft->idr)
return;
- __close_file_table_ids(ft, NULL, session_fd_check);
+ __close_file_table_ids(sess, NULL, session_fd_check);
idr_destroy(ft->idr);
kfree(ft->idr);
ft->idr = NULL;
diff --git a/fs/smb/server/vfs_cache.h b/fs/smb/server/vfs_cache.h
index 78b506c5ef03b..866f32c10d4dd 100644
--- a/fs/smb/server/vfs_cache.h
+++ b/fs/smb/server/vfs_cache.h
@@ -68,6 +68,13 @@ enum {
FP_CLOSED
};
+/* Owner information for durable handle reconnect */
+struct durable_owner {
+ unsigned int uid;
+ unsigned int gid;
+ char *name;
+};
+
struct ksmbd_file {
struct file *filp;
u64 persistent_id;
@@ -114,6 +121,7 @@ struct ksmbd_file {
bool is_resilient;
bool is_posix_ctxt;
+ struct durable_owner owner;
};
static inline void set_ctx_actor(struct dir_context *ctx,
@@ -140,7 +148,7 @@ static inline bool ksmbd_stream_fd(struct ksmbd_file *fp)
}
int ksmbd_init_file_table(struct ksmbd_file_table *ft);
-void ksmbd_destroy_file_table(struct ksmbd_file_table *ft);
+void ksmbd_destroy_file_table(struct ksmbd_session *sess);
int ksmbd_close_fd(struct ksmbd_work *work, u64 id);
struct ksmbd_file *ksmbd_lookup_fd_fast(struct ksmbd_work *work, u64 id);
struct ksmbd_file *ksmbd_lookup_foreign_fd(struct ksmbd_work *work, u64 id);
@@ -166,6 +174,8 @@ void ksmbd_free_global_file_table(void);
void ksmbd_set_fd_limit(unsigned long limit);
void ksmbd_update_fstate(struct ksmbd_file_table *ft, struct ksmbd_file *fp,
unsigned int state);
+bool ksmbd_vfs_compare_durable_owner(struct ksmbd_file *fp,
+ struct ksmbd_user *user);
/*
* INODE hash
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-04-20 16:15 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2026-04-20 14:55 FAILED: patch "[PATCH] ksmbd: validate owner of durable handle on reconnect" failed to apply to 7.0-stable tree gregkh
2026-04-20 16:15 ` [PATCH 7.0.y 1/2] ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger Sasha Levin
2026-04-20 16:15 ` [PATCH 7.0.y 2/2] ksmbd: validate owner of durable handle on reconnect Sasha Levin
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