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ksmbd: validate payload size in ipc response

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[ Upstream commit a677ebd8ca2f2632ccdecbad7b87641274e15aac ]

If installing malicious ksmbd-tools, ksmbd.mountd can return invalid ipc
response to ksmbd kernel server. ksmbd should validate payload size of
ipc response from ksmbd.mountd to avoid memory overrun or
slab-out-of-bounds. This patch validate 3 ipc response that has payload.

Cc: stable@vger.kernel.org
Reported-by: Chao Ma <machao2019@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>
This commit is contained in:
Namjae Jeon 2024-03-31 21:59:10 +09:00 committed by Greg Kroah-Hartman
parent 044b3d6c94
commit 88b7f1143b
3 changed files with 45 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
fs/ksmbd/ksmbd_netlink.h
View File

@ -166,7 +166,8 @@ struct ksmbd_share_config_response {
__u16 force_uid;
__u16 force_gid;
__s8 share_name[KSMBD_REQ_MAX_SHARE_NAME];
__u32 reserved[112]; /* Reserved room */
__u32 reserved[111]; /* Reserved room */
__u32 payload_sz;
__u32 veto_list_sz;
__s8 ____payload[];
};

7
fs/ksmbd/mgmt/share_config.c
View File

@ -158,7 +158,12 @@ static struct ksmbd_share_config *share_config_request(struct unicode_map *um,
share->name = kstrdup(name, GFP_KERNEL);
if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) {
share->path = kstrdup(ksmbd_share_config_path(resp),
int path_len = PATH_MAX;
if (resp->payload_sz)
path_len = resp->payload_sz - resp->veto_list_sz;
share->path = kstrndup(ksmbd_share_config_path(resp), path_len,
GFP_KERNEL);
if (share->path)
share->path_sz = strlen(share->path);

37
fs/ksmbd/transport_ipc.c
View File

@ -65,6 +65,7 @@ struct ipc_msg_table_entry {
struct hlist_node ipc_table_hlist;
void *response;
unsigned int msg_sz;
};
static struct delayed_work ipc_timer_work;
@ -274,6 +275,7 @@ static int handle_response(int type, void *payload, size_t sz)
}
memcpy(entry->response, payload, sz);
entry->msg_sz = sz;
wake_up_interruptible(&entry->wait);
ret = 0;
break;
@ -452,6 +454,34 @@ out:
return ret;
}
static int ipc_validate_msg(struct ipc_msg_table_entry *entry)
{
unsigned int msg_sz = entry->msg_sz;
if (entry->type == KSMBD_EVENT_RPC_REQUEST) {
struct ksmbd_rpc_command *resp = entry->response;
msg_sz = sizeof(struct ksmbd_rpc_command) + resp->payload_sz;
} else if (entry->type == KSMBD_EVENT_SPNEGO_AUTHEN_REQUEST) {
struct ksmbd_spnego_authen_response *resp = entry->response;
msg_sz = sizeof(struct ksmbd_spnego_authen_response) +
resp->session_key_len + resp->spnego_blob_len;
} else if (entry->type == KSMBD_EVENT_SHARE_CONFIG_REQUEST) {
struct ksmbd_share_config_response *resp = entry->response;
if (resp->payload_sz) {
if (resp->payload_sz < resp->veto_list_sz)
return -EINVAL;
msg_sz = sizeof(struct ksmbd_share_config_response) +
resp->payload_sz;
}
}
return entry->msg_sz != msg_sz ? -EINVAL : 0;
}
static void *ipc_msg_send_request(struct ksmbd_ipc_msg *msg, unsigned int handle)
{
struct ipc_msg_table_entry entry;
@ -476,6 +506,13 @@ static void *ipc_msg_send_request(struct ksmbd_ipc_msg *msg, unsigned int handle
ret = wait_event_interruptible_timeout(entry.wait,
entry.response != NULL,
IPC_WAIT_TIMEOUT);
if (entry.response) {
ret = ipc_validate_msg(&entry);
if (ret) {
kvfree(entry.response);
entry.response = NULL;
}
}
out:
down_write(&ipc_msg_table_lock);
hash_del(&entry.ipc_table_hlist);