From 399aa12450a61a5c73dc77e73f069ece9687c95d Mon Sep 17 00:00:00 2001 From: Aleksandr Khromov Date: Mon, 24 Aug 2026 13:22:46 +0300 Subject: [PATCH 01/12] ksmbd: zero the FS_OBJECT_ID_INFORMATION buffer before filling it in smb2_get_info_filesystem() reports 64 bytes for FS_OBJECT_ID_INFORMATION, that is the whole of struct object_id_info, but writes only 46 of them: - objid[] is 16 bytes, and when the volume UUID is not available only sizeof(stfs.f_fsid) (8) bytes are copied into it; - extended_info.version_string[] is STRING_LENGTH (28) bytes, and only strlen("1.1.0") (5) bytes are copied into it. The response buffer is zeroed on allocation (kvzalloc() in smb2_allocate_rsp_buf()), so for a standalone request the remaining 31 bytes are zero. In a compound request they need not be. The offset of the next response is advanced by the length pinned for the previous one, so if a preceding command wrote its reply into the buffer and then failed, smb2_set_err_rsp() pins only the short error response and the next reply lands inside the area that has already been written. Only the header is cleared there: memset((char *)rsp_hdr, 0, sizeof(struct smb2_hdr) + 2); The client then receives up to 31 bytes of a response it was not meant to see, including one that failed with an access denied error. Clear the structure before filling it in. As a side effect version_string is now NUL terminated. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Suggested-by: ChenXiaoSong Cc: stable@vger.kernel.org Signed-off-by: Aleksandr Khromov Signed-off-by: Namjae Jeon --- fs/smb/server/smb2pdu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index a8046f477d54..486cd745dd21 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7444,6 +7444,7 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work, struct object_id_info *info; info = (struct object_id_info *)(rsp->Buffer); + memset(info, 0, sizeof(*info)); if (path.mnt->mnt_sb->s_uuid_len == 16) memcpy(info->objid, path.mnt->mnt_sb->s_uuid.b, From c0cd3fc6824122014da2b3b0cb7ddeaa2946ec8e Mon Sep 17 00:00:00 2001 From: Aleksandr Khromov Date: Mon, 24 Aug 2026 21:23:32 +0900 Subject: [PATCH 02/12] ksmbd: initialize FileSystemControlFlags in FS_CONTROL_INFORMATION smb2_get_info_filesystem() reports 48 bytes for FS_CONTROL_INFORMATION, that is the whole of struct smb2_fs_control_info, but never assigns FileSystemControlFlags. Those four bytes go to the client as they are found in the response buffer. The buffer is zeroed on allocation, so a standalone request leaks nothing. A compound request can leak: the offset of the next response is advanced by the length pinned for the previous one, so a reply that was written into the buffer and then dropped in favour of the short error response of smb2_set_err_rsp() stays there, and the next reply is laid over it with only the header cleared. ksmbd does not implement quota tracking, so report no control flags. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Signed-off-by: Aleksandr Khromov Signed-off-by: Namjae Jeon --- fs/smb/server/smb2pdu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 486cd745dd21..2fbd9010513e 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7500,6 +7500,7 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work, info->FreeSpaceStopFiltering = 0; info->DefaultQuotaThreshold = cpu_to_le64(SMB2_NO_FID); info->DefaultQuotaLimit = cpu_to_le64(SMB2_NO_FID); + info->FileSystemControlFlags = 0; info->Padding = 0; rsp->OutputBufferLength = cpu_to_le32(48); fixed_len = 48; From db2267b27c054a6c2151ff7fbb67927e784f31d6 Mon Sep 17 00:00:00 2001 From: Aleksandr Khromov Date: Tue, 25 Aug 2026 10:19:21 +0900 Subject: [PATCH 03/12] ksmbd: fill in FileSysIdentifier in FS_POSIX_INFORMATION smb2_get_info_filesystem() reports 56 bytes for FS_POSIX_INFORMATION, that is the whole of FILE_SYSTEM_POSIX_INFO, but never assigns FileSysIdentifier. Those eight bytes go to the client as they are found in the response buffer. The buffer is zeroed on allocation, so a standalone request leaks nothing. A compound request can leak: the offset of the next response is advanced by the length pinned for the previous one, so a reply that was written into the buffer and then dropped in favour of the short error response of smb2_set_err_rsp() stays there, and the next reply is laid over it with only the header cleared. Report the file system id statfs() returned, which is what the field is for. FileSysIdentifier is __le64 and f_fsid is a pair of ints, so assemble the value first, val[0] as the low half, and convert it on the way out. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Signed-off-by: Aleksandr Khromov Signed-off-by: Namjae Jeon --- fs/smb/server/smb2pdu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 2fbd9010513e..08cb215c3729 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7523,6 +7523,9 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work, info->UserBlocksAvail = cpu_to_le64(stfs.f_bavail); info->TotalFileNodes = cpu_to_le64(stfs.f_files); info->FreeFileNodes = cpu_to_le64(stfs.f_ffree); + info->FileSysIdentifier = + cpu_to_le64((u64)(u32)stfs.f_fsid.val[1] << 32 | + (u32)stfs.f_fsid.val[0]); rsp->OutputBufferLength = cpu_to_le32(56); fixed_len = 56; } From edcd92df5e1f94e89f8cd410ce41c5cb56e24453 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Wed, 26 Aug 2026 23:03:01 +0900 Subject: [PATCH 04/12] MAINTAINERS: Add Paulo Alcantara as an SMBDIRECT co-maintainer Steve French passed away recently. He was a long-time maintainer of Linux's SMB support and will be greatly missed. Add Paulo Alcantara as a co-maintainer of SMBDIRECT. Acked-by: Paulo Alcantara Signed-off-by: Paulo Alcantara Acked-by: Stefan Metzmacher Signed-off-by: Namjae Jeon --- MAINTAINERS | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index e05570c393c5..7e1d14406619 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -25105,10 +25105,9 @@ F: Documentation/admin-guide/LSM/Smack.rst F: security/smack/ SMBDIRECT (RDMA Stream Transport with Read/Write-Offload, MS-SMBD) -M: Steve French -M: Steve French M: Namjae Jeon M: Namjae Jeon +M: Paulo Alcantara R: Stefan Metzmacher R: Tom Talpey L: linux-cifs@vger.kernel.org From 5c944895a94d0317669f1b3409deb0161eaf916b Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Wed, 26 Aug 2026 23:36:28 +0900 Subject: [PATCH 05/12] MAINTAINERS: Update the KSMBD entry Steve French passed away recently. He was a long-time maintainer of Linux's SMB support and will be greatly missed. Update the KSMBD entry to no longer list Steve French as a maintainer. Signed-off-by: Namjae Jeon --- MAINTAINERS | 2 -- 1 file changed, 2 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 7e1d14406619..2a81760e697b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14194,8 +14194,6 @@ F: tools/testing/selftests/ KERNEL SMB3 SERVER (KSMBD) M: Namjae Jeon M: Namjae Jeon -M: Steve French -M: Steve French R: Sergey Senozhatsky R: Tom Talpey R: ChenXiaoSong From d12168084c8c1b6d883c8eca5853929ac5136a9e Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Fri, 28 Aug 2026 10:46:44 +0900 Subject: [PATCH 06/12] ksmbd: safely drain sessions during logoff SMB3 multichannel allows requests for one session to run on multiple connections. Wait for all channels bound to a session before freeing shared session objects. A deferred byte-range lock remains counted as a running request and only wakes when its file closes. Wake blocked locks during the drain without unpublishing or modifying their file objects. Synchronous CANCEL requests must invoke their cancellation callback to wake pending operations, while CHANGE_NOTIFY completion remains specific to the asynchronous path. Serialize session teardown with channel registration and previous-session cleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and connection teardown invoke cancellation callbacks only once. Fixes: 76e98a158b20 ("ksmbd: fix race condition between destroy_previous_session() and smb2 operations()") Reported-by: Cheryl Babcock Signed-off-by: Namjae Jeon --- fs/smb/server/connection.c | 8 ++++-- fs/smb/server/mgmt/user_session.c | 13 ++++++++- fs/smb/server/mgmt/user_session.h | 1 + fs/smb/server/smb2pdu.c | 47 +++++++++++++++++++++++++++---- fs/smb/server/vfs_cache.c | 17 +++++++++-- fs/smb/server/vfs_cache.h | 1 + 6 files changed, 77 insertions(+), 10 deletions(-) diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index 91fdd1ddc61f..4cb92d6599ee 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -13,6 +13,7 @@ #include "mgmt/ksmbd_ida.h" #include "mgmt/user_session.h" #include "connection.h" +#include "vfs_cache.h" #include "compress.h" #include "transport_tcp.h" #include "transport_rdma.h" @@ -384,12 +385,12 @@ static void ksmbd_conn_cancel_async_requests(struct ksmbd_conn *conn) spin_lock(&conn->request_lock); list_for_each_entry_safe(work, tmp, &conn->async_requests, async_request_entry) { - if (work->state != KSMBD_WORK_ACTIVE) + if (cmpxchg(&work->state, KSMBD_WORK_ACTIVE, + KSMBD_WORK_CANCELLED) != KSMBD_WORK_ACTIVE) continue; ksmbd_debug(CONN, "Cancel async request id %d\n", work->async_id); - work->state = KSMBD_WORK_CANCELLED; if (work->cancel_fn) work->cancel_fn(work->cancel_argv); } @@ -473,6 +474,9 @@ int ksmbd_conn_wait_idle_sess(struct ksmbd_conn *curr_conn, if (retry_count >= max_timeout) return -EIO; + /* A blocked byte-range lock cannot drain until teardown wakes it. */ + ksmbd_wake_session_blocked_works(sess); + down_read(&conn_list_lock); hash_for_each(conn_list, bkt, conn, hlist) { if (ksmbd_session_is_bound_to_conn(sess, conn)) { diff --git a/fs/smb/server/mgmt/user_session.c b/fs/smb/server/mgmt/user_session.c index 7022d5d656b4..2eb8f730e99e 100644 --- a/fs/smb/server/mgmt/user_session.c +++ b/fs/smb/server/mgmt/user_session.c @@ -666,10 +666,21 @@ void destroy_previous_session(struct ksmbd_conn *conn, memcmp(user->passkey, prev_user->passkey, user->passkey_sz)) goto out; + down_write(&prev_sess->chann_lock); + if (prev_sess->tearing_down) { + up_write(&prev_sess->chann_lock); + goto out; + } + prev_sess->tearing_down = true; + up_write(&prev_sess->chann_lock); + ksmbd_all_conn_set_status(prev_sess, KSMBD_SESS_NEED_RECONNECT); err = ksmbd_conn_wait_idle_sess(conn, prev_sess); if (err) { - ksmbd_all_conn_set_status(prev_sess, KSMBD_SESS_NEED_SETUP); + down_write(&prev_sess->chann_lock); + prev_sess->tearing_down = false; + up_write(&prev_sess->chann_lock); + ksmbd_all_conn_set_status(prev_sess, KSMBD_SESS_GOOD); goto out; } diff --git a/fs/smb/server/mgmt/user_session.h b/fs/smb/server/mgmt/user_session.h index f8a24c33f7fe..3e52d4cc1324 100644 --- a/fs/smb/server/mgmt/user_session.h +++ b/fs/smb/server/mgmt/user_session.h @@ -42,6 +42,7 @@ struct ksmbd_session { bool sign; bool enc; + bool tearing_down; int state; __u8 *Preauth_HashValue; diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 08cb215c3729..ba0fe25bf366 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -97,6 +97,11 @@ static int register_session_channel(struct ksmbd_session *sess, int rc = 0; down_write(&sess->chann_lock); + if (sess->tearing_down) { + rc = -ESHUTDOWN; + goto out; + } + if (xa_load(&sess->ksmbd_chann_list, (long)conn)) goto out; @@ -3086,17 +3091,41 @@ int smb2_session_logoff(struct ksmbd_work *work) smb2_set_err_rsp(work); return -ENOENT; } + + down_write(&sess->chann_lock); + if (sess->tearing_down) { + up_write(&sess->chann_lock); + ksmbd_conn_unlock(conn); + rsp->hdr.Status = STATUS_USER_SESSION_DELETED; + smb2_set_err_rsp(work); + return -ENOENT; + } + sess->tearing_down = true; + up_write(&sess->chann_lock); + ksmbd_all_conn_set_status(sess, KSMBD_SESS_NEED_RECONNECT); ksmbd_conn_unlock(conn); + err = ksmbd_conn_wait_idle_sess(conn, sess); + if (err) { + down_write(&sess->chann_lock); + sess->tearing_down = false; + up_write(&sess->chann_lock); + ksmbd_all_conn_set_status(sess, KSMBD_SESS_GOOD); + rsp->hdr.Status = STATUS_UNEXPECTED_IO_ERROR; + smb2_set_err_rsp(work); + return err; + } + ksmbd_close_session_fds(work); - ksmbd_conn_wait_idle(conn); if (ksmbd_tree_conn_session_logoff(sess)) { ksmbd_debug(SMB, "Invalid tid %d\n", req->hdr.Id.SyncId.TreeId); rsp->hdr.Status = STATUS_NETWORK_NAME_DELETED; smb2_set_err_rsp(work); - return -ENOENT; + err = -ENOENT; + } else { + err = 0; } down_write(&conn->session_lock); @@ -3106,6 +3135,9 @@ int smb2_session_logoff(struct ksmbd_work *work) ksmbd_all_conn_set_status(sess, KSMBD_SESS_NEED_SETUP); + if (err) + return err; + rsp->StructureSize = cpu_to_le16(4); err = ksmbd_iov_pin_rsp(work, rsp, sizeof(struct smb2_logoff_rsp)); if (err) { @@ -9685,14 +9717,14 @@ int smb2_cancel(struct ksmbd_work *work) * still on conn->async_requests with a live cancel_fn * pointing at the freed file_lock. */ - if (iter->state != KSMBD_WORK_ACTIVE) + if (cmpxchg(&iter->state, KSMBD_WORK_ACTIVE, + KSMBD_WORK_CANCELLED) != KSMBD_WORK_ACTIVE) break; ksmbd_debug(SMB, "smb2 with AsyncId %llu cancelled command = 0x%x\n", le64_to_cpu(hdr->Id.AsyncId), le16_to_cpu(chdr->Command)); - iter->state = KSMBD_WORK_CANCELLED; if (iter->cancel_fn == smb2_notify_cancel_fn) cancelled_notify = smb2_notify_cancel_claim(iter->cancel_argv); @@ -9721,11 +9753,16 @@ int smb2_cancel(struct ksmbd_work *work) iter == work) continue; + if (cmpxchg(&iter->state, KSMBD_WORK_ACTIVE, + KSMBD_WORK_CANCELLED) != KSMBD_WORK_ACTIVE) + break; + ksmbd_debug(SMB, "smb2 with mid %llu cancelled command = 0x%x\n", le64_to_cpu(hdr->MessageId), le16_to_cpu(chdr->Command)); - iter->state = KSMBD_WORK_CANCELLED; + if (iter->cancel_fn) + iter->cancel_fn(iter->cancel_argv); break; } spin_unlock(&conn->request_lock); diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c index 81626d204249..fd2c595f0486 100644 --- a/fs/smb/server/vfs_cache.c +++ b/fs/smb/server/vfs_cache.c @@ -846,12 +846,25 @@ static void set_close_state_blocked_works(struct ksmbd_file *fp) spin_lock(&fp->f_lock); list_for_each_entry(cancel_work, &fp->blocked_works, fp_entry) { - cancel_work->state = KSMBD_WORK_CLOSED; - cancel_work->cancel_fn(cancel_work->cancel_argv); + if (xchg(&cancel_work->state, KSMBD_WORK_CLOSED) == + KSMBD_WORK_ACTIVE) + cancel_work->cancel_fn(cancel_work->cancel_argv); } spin_unlock(&fp->f_lock); } +void ksmbd_wake_session_blocked_works(struct ksmbd_session *sess) +{ + struct ksmbd_file_table *ft = &sess->file_table; + struct ksmbd_file *fp; + unsigned int id; + + read_lock(&ft->lock); + idr_for_each_entry(ft->idr, fp, id) + set_close_state_blocked_works(fp); + read_unlock(&ft->lock); +} + int ksmbd_close_fd(struct ksmbd_work *work, u64 id) { struct ksmbd_file *fp; diff --git a/fs/smb/server/vfs_cache.h b/fs/smb/server/vfs_cache.h index 502efb16f05f..1884f6deb9d0 100644 --- a/fs/smb/server/vfs_cache.h +++ b/fs/smb/server/vfs_cache.h @@ -226,6 +226,7 @@ void ksmbd_stop_durable_scavenger(void); bool ksmbd_durable_scavenger_active(void); void ksmbd_close_tree_conn_fds(struct ksmbd_work *work); void ksmbd_close_session_fds(struct ksmbd_work *work); +void ksmbd_wake_session_blocked_works(struct ksmbd_session *sess); int ksmbd_close_inode_fds(struct ksmbd_work *work, struct inode *inode); int ksmbd_init_global_file_table(void); void ksmbd_free_global_file_table(void); From 73f860489e3be2245598d1819226304fc5b87291 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Tue, 25 Aug 2026 09:31:35 +0900 Subject: [PATCH 07/12] ksmbd: zero pipe read compound padding Compound response handling extends the last response iov to an eight-byte boundary. smb2_read_pipe() allocates only the payload size, so the alignment padding can expose up to seven bytes of uninitialized kernel heap memory. Allocate the aligned size and clear the unused tail before pinning the response buffer. Fixes: e2b76ab8b5c9 ("ksmbd: add support for read compound") Reported-by: Cheryl Babcock Signed-off-by: Namjae Jeon --- fs/smb/server/smb2pdu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index ba0fe25bf366..8c589110460a 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -8657,13 +8657,18 @@ static noinline int smb2_read_pipe(struct ksmbd_work *work) } aux_payload_buf = - kvmalloc(rpc_resp->payload_sz, KSMBD_DEFAULT_GFP); + kvmalloc(ALIGN(rpc_resp->payload_sz, 8), + KSMBD_DEFAULT_GFP); if (!aux_payload_buf) { err = -ENOMEM; goto out; } memcpy(aux_payload_buf, rpc_resp->payload, rpc_resp->payload_sz); + if (rpc_resp->payload_sz & 7) + memset(aux_payload_buf + rpc_resp->payload_sz, 0, + ALIGN(rpc_resp->payload_sz, 8) - + rpc_resp->payload_sz); nbytes = rpc_resp->payload_sz; err = ksmbd_iov_pin_rsp_read(work, (void *)rsp, From c61dc7b1b4a3234b4aa3965502908a292238805c Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Tue, 25 Aug 2026 09:32:07 +0900 Subject: [PATCH 08/12] ksmbd: propagate DACL parsing errors parse_dacl() silently accepts truncated ACEs and allocation failures, allowing set_info_sec() to continue with an incomplete ACL conversion. Return parsing and allocation errors to parse_sec_desc() so malformed security descriptors are rejected before inode attributes or ACL xattrs are updated. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Reported-by: Cheryl Babcock Signed-off-by: Namjae Jeon --- fs/smb/server/smbacl.c | 63 +++++++++++++++++++++++++----------------- 1 file changed, 38 insertions(+), 25 deletions(-) diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c index 8ad2e5a5cca8..4496098eb559 100644 --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -383,10 +383,10 @@ void free_acl_state(struct posix_acl_state *state) kfree(state->groups); } -static void parse_dacl(struct mnt_idmap *idmap, - struct smb_acl *pdacl, char *end_of_acl, - struct smb_sid *pownersid, struct smb_sid *pgrpsid, - struct smb_fattr *fattr) +static int parse_dacl(struct mnt_idmap *idmap, + struct smb_acl *pdacl, char *end_of_acl, + struct smb_sid *pownersid, struct smb_sid *pgrpsid, + struct smb_fattr *fattr) { int i, ret; u16 num_aces = 0; @@ -400,13 +400,13 @@ static void parse_dacl(struct mnt_idmap *idmap, bool owner_found = false, group_found = false, others_found = false; if (!pdacl) - return; + return 0; /* validate that we do not go past end of acl */ if (end_of_acl < (char *)pdacl + sizeof(struct smb_acl) || end_of_acl < (char *)pdacl + le16_to_cpu(pdacl->size)) { pr_err("ACL too small to parse DACL\n"); - return; + return -EINVAL; } ksmbd_debug(SMB, "DACL revision %d size %d num aces %d\n", @@ -418,31 +418,31 @@ static void parse_dacl(struct mnt_idmap *idmap, num_aces = le16_to_cpu(pdacl->num_aces); if (num_aces <= 0) - return; + return 0; dacl_size = le16_to_cpu(pdacl->size); if (dacl_size < sizeof(struct smb_acl)) - return; + return -EINVAL; if (num_aces > (dacl_size - sizeof(struct smb_acl)) / (offsetof(struct smb_ace, sid) + offsetof(struct smb_sid, sub_auth) + sizeof(__le16))) - return; + return -EINVAL; ret = init_acl_state(&acl_state, num_aces); if (ret) - return; + return ret; ret = init_acl_state(&default_acl_state, num_aces); if (ret) { free_acl_state(&acl_state); - return; + return ret; } ppace = kmalloc_objs(struct smb_ace *, num_aces, KSMBD_DEFAULT_GFP); if (!ppace) { free_acl_state(&default_acl_state); free_acl_state(&acl_state); - return; + return -ENOMEM; } /* @@ -451,8 +451,10 @@ static void parse_dacl(struct mnt_idmap *idmap, * user/group/other have no permissions */ for (i = 0; i < num_aces; ++i) { - if (end_of_acl - acl_base < acl_size) - break; + if (end_of_acl - acl_base < acl_size) { + ret = -EINVAL; + goto out; + } ppace[i] = (struct smb_ace *)(acl_base + acl_size); acl_base = (char *)ppace[i]; @@ -465,8 +467,10 @@ static void parse_dacl(struct mnt_idmap *idmap, (end_of_acl - acl_base < acl_size + sizeof(__le32) * ppace[i]->sid.num_subauth) || (le16_to_cpu(ppace[i]->size) < - acl_size + sizeof(__le32) * ppace[i]->sid.num_subauth)) - break; + acl_size + sizeof(__le32) * ppace[i]->sid.num_subauth)) { + ret = -EINVAL; + goto out; + } acl_size = le16_to_cpu(ppace[i]->size); ppace[i]->access_req = @@ -541,7 +545,6 @@ static void parse_dacl(struct mnt_idmap *idmap, ((acl_mode & 0700) >> 6) | 0004; } } - kfree(ppace); if (owner_found) { /* The owner must be set to at least read-only. */ @@ -584,10 +587,12 @@ static void parse_dacl(struct mnt_idmap *idmap, fattr->cf_acls = posix_acl_alloc(acl_state.users->n + acl_state.groups->n + 4, KSMBD_DEFAULT_GFP); - if (fattr->cf_acls) { - cf_pace = fattr->cf_acls->a_entries; - posix_state_to_acl(&acl_state, cf_pace); + if (!fattr->cf_acls) { + ret = -ENOMEM; + goto out; } + cf_pace = fattr->cf_acls->a_entries; + posix_state_to_acl(&acl_state, cf_pace); } } @@ -598,14 +603,20 @@ static void parse_dacl(struct mnt_idmap *idmap, fattr->cf_dacls = posix_acl_alloc(default_acl_state.users->n + default_acl_state.groups->n + 4, KSMBD_DEFAULT_GFP); - if (fattr->cf_dacls) { - cf_pdace = fattr->cf_dacls->a_entries; - posix_state_to_acl(&default_acl_state, cf_pdace); + if (!fattr->cf_dacls) { + ret = -ENOMEM; + goto out; } + cf_pdace = fattr->cf_dacls->a_entries; + posix_state_to_acl(&default_acl_state, cf_pdace); } } + ret = 0; +out: + kfree(ppace); free_acl_state(&acl_state); free_acl_state(&default_acl_state); + return ret; } static void set_posix_acl_entries_dacl(struct mnt_idmap *idmap, @@ -966,8 +977,10 @@ int parse_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd, if (dacloffset < sizeof(struct smb_ntsd)) return -EINVAL; - parse_dacl(idmap, dacl_ptr, end_of_acl, - owner_sid_ptr, group_sid_ptr, fattr); + rc = parse_dacl(idmap, dacl_ptr, end_of_acl, + owner_sid_ptr, group_sid_ptr, fattr); + if (rc) + return rc; } return 0; From feca5e70fc963b088377b20879e8cd8237c2fd7d Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Tue, 25 Aug 2026 09:32:23 +0900 Subject: [PATCH 09/12] ksmbd: rate limit unmapped SID errors A client can include many structurally valid but unmapped SIDs in a DACL. Logging every mapping failure lets one request generate hundreds of kernel error messages. Rate limit the message to prevent an authenticated client from flooding the kernel log. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Reported-by: Cheryl Babcock Signed-off-by: Namjae Jeon --- fs/smb/server/smbacl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c index 4496098eb559..1fad6ccf3a72 100644 --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -528,8 +528,8 @@ static int parse_dacl(struct mnt_idmap *idmap, temp_fattr.cf_uid = INVALID_UID; ret = sid_to_id(idmap, &ppace[i]->sid, SIDOWNER, &temp_fattr); if (ret || uid_eq(temp_fattr.cf_uid, INVALID_UID)) { - pr_err("%s: Error %d mapping Owner SID to uid\n", - __func__, ret); + pr_err_ratelimited("%s: Error %d mapping Owner SID to uid\n", + __func__, ret); continue; } From f25e93768fcc5d8287e50b1ec52a42e4c276df34 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Fri, 28 Aug 2026 08:39:57 +0900 Subject: [PATCH 10/12] ksmbd: prevent out-of-bounds reads in share config responses Validate IPC share configuration payload sizes before consuming variable-length fields. Bound veto list parsing and account for the separator byte when deriving the path length. Fixes: a677ebd8ca2f ("ksmbd: validate payload size in ipc response") Reported-by: Kanishka De Silva Reported-by: Farhad Alemi Signed-off-by: Namjae Jeon --- fs/smb/server/mgmt/share_config.c | 40 +++++++++++++++++++++---------- fs/smb/server/transport_ipc.c | 21 ++++++++++------ 2 files changed, 41 insertions(+), 20 deletions(-) diff --git a/fs/smb/server/mgmt/share_config.c b/fs/smb/server/mgmt/share_config.c index b2d9580bddc6..cc9f18ede80d 100644 --- a/fs/smb/server/mgmt/share_config.c +++ b/fs/smb/server/mgmt/share_config.c @@ -146,9 +146,9 @@ static struct ksmbd_share_config *__share_lookup(const char *name) static int parse_veto_list(struct ksmbd_share_config *share, char *veto_list, - int veto_list_sz) + size_t veto_list_sz) { - int sz = 0; + size_t sz; if (!veto_list_sz) return 0; @@ -156,7 +156,7 @@ static int parse_veto_list(struct ksmbd_share_config *share, while (veto_list_sz > 0) { struct ksmbd_veto_pattern *p; - sz = strlen(veto_list); + sz = strnlen(veto_list, veto_list_sz); if (!sz) break; @@ -164,7 +164,7 @@ static int parse_veto_list(struct ksmbd_share_config *share, if (!p) return -ENOMEM; - p->pattern = kstrdup(veto_list, KSMBD_DEFAULT_GFP); + p->pattern = kstrndup(veto_list, sz, KSMBD_DEFAULT_GFP); if (!p->pattern) { kfree(p); return -ENOMEM; @@ -172,6 +172,9 @@ static int parse_veto_list(struct ksmbd_share_config *share, list_add(&p->list, &share->veto_list); + if (sz == veto_list_sz) + break; + veto_list += sz + 1; veto_list_sz -= (sz + 1); } @@ -224,17 +227,28 @@ static struct ksmbd_share_config *share_config_request(struct ksmbd_work *work, } if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) { - int path_len = PATH_MAX; + size_t path_len; - if (resp->payload_sz) - path_len = resp->payload_sz - resp->veto_list_sz; - - share->path = kstrndup(ksmbd_share_config_path(resp), path_len, - KSMBD_DEFAULT_GFP); - if (!share->path) { - ret = -ENOMEM; + if (resp->payload_sz <= resp->veto_list_sz) { + ret = -EINVAL; } else { - ret = 0; + path_len = resp->payload_sz - resp->veto_list_sz; + if (resp->veto_list_sz) + path_len--; + + if (!path_len) { + ret = -EINVAL; + } else { + share->path = kstrndup( + ksmbd_share_config_path(resp), + path_len, KSMBD_DEFAULT_GFP); + if (!share->path) + ret = -ENOMEM; + else + ret = 0; + } + } + if (share->path) { share->path_sz = strlen(share->path); while (share->path_sz > 1 && share->path[share->path_sz - 1] == '/') diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index 4b0b572a3e1b..e550aa41ad2c 100644 --- a/fs/smb/server/transport_ipc.c +++ b/fs/smb/server/transport_ipc.c @@ -532,14 +532,21 @@ static int ipc_validate_msg(struct ipc_msg_table_entry *entry) if (entry->msg_sz < sizeof(struct ksmbd_share_config_response)) return -EINVAL; - if (resp->payload_sz) { - if (resp->payload_sz < resp->veto_list_sz) - return -EINVAL; + if (strnlen(resp->share_name, sizeof(resp->share_name)) == + sizeof(resp->share_name)) + return -EINVAL; - if (check_add_overflow(sizeof(struct ksmbd_share_config_response), - resp->payload_sz, &msg_sz)) - return -EINVAL; - } + if (resp->veto_list_sz > resp->payload_sz) + return -EINVAL; + + if (resp->flags != KSMBD_SHARE_FLAG_INVALID && + !(resp->flags & KSMBD_SHARE_FLAG_PIPE) && + resp->payload_sz <= resp->veto_list_sz) + return -EINVAL; + + if (check_add_overflow(sizeof(struct ksmbd_share_config_response), + resp->payload_sz, &msg_sz)) + return -EINVAL; break; } case KSMBD_EVENT_LOGIN_REQUEST_EXT: From a506290f59e1c6ce9ac0a13158640bb8fee93471 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Fri, 28 Aug 2026 09:24:49 +0900 Subject: [PATCH 11/12] ksmbd: fix listener task lifetime on netdev events The listener thread exits when its listening socket is shutdown. The netdevice notifier shuts down the socket before calling kthread_stop(), so the task_struct can be freed before kthread_stop() gets its reference. Create the listener in a stopped state and hold an extra task_struct reference until kthread_stop_put() completes. Also stop and release listeners before freeing their interface records during TCP teardown. Fixes: 3316a8fc840d ("ksmbd: server: avoid busy polling in accept loop") Reported-by: Farhad Alemi Signed-off-by: Namjae Jeon --- fs/smb/server/transport_tcp.c | 36 ++++++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 9 deletions(-) diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 832e93084605..4968cfc1a572 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -39,6 +39,7 @@ struct tcp_transport { static const struct ksmbd_transport_ops ksmbd_tcp_transport_ops; static void tcp_stop_kthread(struct task_struct *kthread); +static void ksmbd_tcp_stop_listener(struct interface *iface); static struct interface *alloc_iface(char *ifname); static void ksmbd_tcp_disconnect(struct ksmbd_transport *t); @@ -321,13 +322,20 @@ static int ksmbd_tcp_run_kthread(struct interface *iface) int rc; struct task_struct *kthread; - kthread = kthread_run(ksmbd_kthread_fn, (void *)iface, "ksmbd-%s", - iface->name); + kthread = kthread_create(ksmbd_kthread_fn, (void *)iface, "ksmbd-%s", + iface->name); if (IS_ERR(kthread)) { rc = PTR_ERR(kthread); return rc; } + + /* + * The listener can exit after its socket is shutdown, so keep the + * task_struct alive until the caller has stopped it. + */ + get_task_struct(kthread); iface->ksmbd_kthread = kthread; + wake_up_process(kthread); return 0; } @@ -598,12 +606,7 @@ static int ksmbd_netdev_event(struct notifier_block *nb, unsigned long event, if (iface && iface->state == IFACE_STATE_CONFIGURED) { ksmbd_debug(CONN, "netdev-down event: netdev(%s) is going down\n", iface->name); - kernel_sock_shutdown(iface->ksmbd_socket, SHUT_RDWR); - tcp_stop_kthread(iface->ksmbd_kthread); - iface->ksmbd_kthread = NULL; - sock_release(iface->ksmbd_socket); - iface->ksmbd_socket = NULL; - + ksmbd_tcp_stop_listener(iface); iface->state = IFACE_STATE_DOWN; break; } @@ -631,11 +634,25 @@ static void tcp_stop_kthread(struct task_struct *kthread) if (!kthread) return; - ret = kthread_stop(kthread); + ret = kthread_stop_put(kthread); if (ret) pr_err("failed to stop forker thread\n"); } +static void ksmbd_tcp_stop_listener(struct interface *iface) +{ + if (iface->ksmbd_socket) + kernel_sock_shutdown(iface->ksmbd_socket, SHUT_RDWR); + + tcp_stop_kthread(iface->ksmbd_kthread); + iface->ksmbd_kthread = NULL; + + if (iface->ksmbd_socket) { + sock_release(iface->ksmbd_socket); + iface->ksmbd_socket = NULL; + } +} + void ksmbd_tcp_destroy(void) { struct interface *iface, *tmp; @@ -643,6 +660,7 @@ void ksmbd_tcp_destroy(void) unregister_netdevice_notifier(&ksmbd_netdev_notifier); list_for_each_entry_safe(iface, tmp, &iface_list, entry) { + ksmbd_tcp_stop_listener(iface); list_del(&iface->entry); kfree(iface->name); kfree(iface); From ba9572bc43d04d71ba52ae7f20645f1eafe86875 Mon Sep 17 00:00:00 2001 From: Alon Shakevsky Date: Sat, 29 Aug 2026 06:27:46 +0000 Subject: [PATCH 12/12] ksmbd: validate normalized name response length FILE_NORMALIZED_NAME_INFORMATION converts the open file path to UTF-16. smb2_allocate_rsp_buf() leaves these responses in the 448-byte small buffer, and get_file_normalized_name_info() converts the path without checking the remaining space. An authenticated client can query a long path and make smbConvertToUTF16() write beyond work->response_buf. Use the large response buffer for normalized-name queries. Before conversion, verify that the response has room for the worst-case UTF-16 output and its terminator. Fixes: 10aeff72ab82 ("ksmbd: support normalized name information") Assisted-by: Antiproof:GPT-5.6-Sol Signed-off-by: Alon Shakevsky Signed-off-by: Namjae Jeon --- fs/smb/server/smb2pdu.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 8c589110460a..d656832d82ef 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -878,7 +878,8 @@ int smb2_allocate_rsp_buf(struct ksmbd_work *work) req = smb_get_msg(work->request_buf); if ((req->InfoType == SMB2_O_INFO_FILE && (req->FileInfoClass == FILE_FULL_EA_INFORMATION || - req->FileInfoClass == FILE_ALL_INFORMATION)) || + req->FileInfoClass == FILE_ALL_INFORMATION || + req->FileInfoClass == FILE_NORMALIZED_NAME_INFORMATION)) || req->InfoType == SMB2_O_INFO_SECURITY) sz = large_sz; } @@ -6789,7 +6790,7 @@ static int get_file_normalized_name_info(struct ksmbd_work *work, { struct smb2_file_alt_name_info *file_info; char *filename, *normalized, *stream_name; - int conv_len, filename_len; + int buf_free_len, conv_len, filename_len; if (work->conn->dialect < SMB311_PROT_ID) { rsp->hdr.Status = STATUS_NOT_SUPPORTED; @@ -6813,6 +6814,14 @@ static int get_file_normalized_name_info(struct ksmbd_work *work, return -ENOMEM; filename_len = strlen(normalized); + buf_free_len = smb2_resp_buf_len(work, sizeof(*rsp) + + sizeof(*file_info)); + if (buf_free_len < 0 || + (size_t)buf_free_len < (filename_len + 1) * sizeof(__le16)) { + kfree(normalized); + return -EINVAL; + } + file_info = (struct smb2_file_alt_name_info *)rsp->Buffer; conv_len = smbConvertToUTF16((__le16 *)file_info->FileName, normalized, filename_len,