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From: ronnie sahlberg <ronniesahlberg@gmail.com>
To: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs <linux-cifs@vger.kernel.org>,
	"Ralph Böhme" <slow@samba.org>,
	"Steve French" <smfrench@gmail.com>
Subject: Re: [PATCH v3] ksmbd: add validation in smb2_ioctl
Date: Wed, 22 Sep 2021 14:08:04 +1000	[thread overview]
Message-ID: <CAN05THQxkVzGXZXunqdb-ZpQe+KA0YXjL7tTMKOeEhd_Cv8=Lg@mail.gmail.com> (raw)
In-Reply-To: <CAN05THQGvRqAsej02b6uje8duTAoOv_tdnT9dLHyWg1pDrsXJA@mail.gmail.com>

Ignore.  Looking at the wrong code.

On Wed, Sep 22, 2021 at 1:48 PM ronnie sahlberg
<ronniesahlberg@gmail.com> wrote:
>
> I hope I look at the right patches/branches, appologies if not.
>
> Do you have a branch where you have all these patches applied?
>
> On Wed, Sep 22, 2021 at 12:28 PM Namjae Jeon <linkinjeon@kernel.org> wrote:
> >
> > Add validation for request/response buffer size check in smb2_ioctl and
> > fsctl_copychunk() take copychunk_ioctl_req pointer and the other arguments
> > instead of smb2_ioctl_req structure and remove an unused smb2_ioctl_req
> > argument of fsctl_validate_negotiate_info.
> >
> > Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
> > Cc: Ralph Böhme <slow@samba.org>
> > Cc: Steve French <smfrench@gmail.com>
> > Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
> > ---
> >  v2:
> >    - fix warning: variable 'ret' is used uninitialized ret.
> >  v3:
> >    - fsctl_copychunk() take copychunk_ioctl_req pointer and the other arguments
> >      instead of smb2_ioctl_req structure.
> >    - remove an unused smb2_ioctl_req argument of fsctl_validate_negotiate_info.
> >  fs/ksmbd/smb2pdu.c | 87 ++++++++++++++++++++++++++++++++++++----------
> >  1 file changed, 68 insertions(+), 19 deletions(-)
> >
> > diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
> > index aaf50f677194..e96491c9ab92 100644
> > --- a/fs/ksmbd/smb2pdu.c
> > +++ b/fs/ksmbd/smb2pdu.c
> > @@ -6986,24 +6986,26 @@ int smb2_lock(struct ksmbd_work *work)
> >         return err;
> >  }
> >
> > -static int fsctl_copychunk(struct ksmbd_work *work, struct smb2_ioctl_req *req,
> > +static int fsctl_copychunk(struct ksmbd_work *work,
> > +                          struct copychunk_ioctl_req *ci_req,
> > +                          unsigned int cnt_code,
> > +                          unsigned int input_count,
> > +                          unsigned long long volatile_id,
> > +                          unsigned long long persistent_id,
> >                            struct smb2_ioctl_rsp *rsp)
> >  {
> > -       struct copychunk_ioctl_req *ci_req;
> >         struct copychunk_ioctl_rsp *ci_rsp;
> >         struct ksmbd_file *src_fp = NULL, *dst_fp = NULL;
> >         struct srv_copychunk *chunks;
> >         unsigned int i, chunk_count, chunk_count_written = 0;
> >         unsigned int chunk_size_written = 0;
> >         loff_t total_size_written = 0;
> > -       int ret, cnt_code;
> > +       int ret = 0;
> >
> > -       cnt_code = le32_to_cpu(req->CntCode);
> > -       ci_req = (struct copychunk_ioctl_req *)&req->Buffer[0];
> >         ci_rsp = (struct copychunk_ioctl_rsp *)&rsp->Buffer[0];
> >
> > -       rsp->VolatileFileId = req->VolatileFileId;
> > -       rsp->PersistentFileId = req->PersistentFileId;
> > +       rsp->VolatileFileId = cpu_to_le64(volatile_id);
> > +       rsp->PersistentFileId = cpu_to_le64(persistent_id);
> >         ci_rsp->ChunksWritten =
> >                 cpu_to_le32(ksmbd_server_side_copy_max_chunk_count());
> >         ci_rsp->ChunkBytesWritten =
> > @@ -7013,12 +7015,13 @@ static int fsctl_copychunk(struct ksmbd_work *work, struct smb2_ioctl_req *req,
> >
> >         chunks = (struct srv_copychunk *)&ci_req->Chunks[0];
> >         chunk_count = le32_to_cpu(ci_req->ChunkCount);
> > +       if (chunk_count == 0)
> > +               goto out;
> >         total_size_written = 0;
> >
> >         /* verify the SRV_COPYCHUNK_COPY packet */
> >         if (chunk_count > ksmbd_server_side_copy_max_chunk_count() ||
> > -           le32_to_cpu(req->InputCount) <
> > -            offsetof(struct copychunk_ioctl_req, Chunks) +
> > +           input_count < offsetof(struct copychunk_ioctl_req, Chunks) +
> >              chunk_count * sizeof(struct srv_copychunk)) {
> >                 rsp->hdr.Status = STATUS_INVALID_PARAMETER;
> >                 return -EINVAL;
> > @@ -7039,9 +7042,7 @@ static int fsctl_copychunk(struct ksmbd_work *work, struct smb2_ioctl_req *req,
> >
> >         src_fp = ksmbd_lookup_foreign_fd(work,
> >                                          le64_to_cpu(ci_req->ResumeKey[0]));
> > -       dst_fp = ksmbd_lookup_fd_slow(work,
> > -                                     le64_to_cpu(req->VolatileFileId),
> > -                                     le64_to_cpu(req->PersistentFileId));
> > +       dst_fp = ksmbd_lookup_fd_slow(work, volatile_id, persistent_id);
> >         ret = -EINVAL;
> >         if (!src_fp ||
> >             src_fp->persistent_id != le64_to_cpu(ci_req->ResumeKey[1])) {
> > @@ -7116,8 +7117,8 @@ static __be32 idev_ipv4_address(struct in_device *idev)
> >  }
> >
> >  static int fsctl_query_iface_info_ioctl(struct ksmbd_conn *conn,
> > -                                       struct smb2_ioctl_req *req,
> > -                                       struct smb2_ioctl_rsp *rsp)
> > +                                       struct smb2_ioctl_rsp *rsp,
> > +                                       int out_buf_len)
> >  {
> >         struct network_interface_info_ioctl_rsp *nii_rsp = NULL;
> >         int nbytes = 0;
> > @@ -7200,6 +7201,8 @@ static int fsctl_query_iface_info_ioctl(struct ksmbd_conn *conn,
> >                         sockaddr_storage->addr6.ScopeId = 0;
> >                 }
> >
> > +               if (out_buf_len < sizeof(struct network_interface_info_ioctl_rsp))
> > +                       break;
> >                 nbytes += sizeof(struct network_interface_info_ioctl_rsp);
> >         }
> >         rtnl_unlock();
> > @@ -7220,11 +7223,16 @@ static int fsctl_query_iface_info_ioctl(struct ksmbd_conn *conn,
> >
> >  static int fsctl_validate_negotiate_info(struct ksmbd_conn *conn,
> >                                          struct validate_negotiate_info_req *neg_req,
> > -                                        struct validate_negotiate_info_rsp *neg_rsp)
> > +                                        struct validate_negotiate_info_rsp *neg_rsp,
> > +                                        int in_buf_len)
> >  {
> >         int ret = 0;
> >         int dialect;
> >
> > +       if (in_buf_len < sizeof(struct validate_negotiate_info_req) +
> > +                       le16_to_cpu(neg_req->DialectCount) * sizeof(__le16))
> > +               return -EINVAL;
> > +
> >         dialect = ksmbd_lookup_dialect_by_id(neg_req->Dialects,
> >                                              neg_req->DialectCount);
> >         if (dialect == BAD_PROT_ID || dialect != conn->dialect) {
> > @@ -7400,7 +7408,7 @@ int smb2_ioctl(struct ksmbd_work *work)
> >         struct smb2_ioctl_req *req;
> >         struct smb2_ioctl_rsp *rsp, *rsp_org;
> >         int cnt_code, nbytes = 0;
> > -       int out_buf_len;
> > +       int out_buf_len, in_buf_len;
> >         u64 id = KSMBD_NO_FID;
> >         struct ksmbd_conn *conn = work->conn;
> >         int ret = 0;
> > @@ -7430,6 +7438,7 @@ int smb2_ioctl(struct ksmbd_work *work)
> >         cnt_code = le32_to_cpu(req->CntCode);
> >         out_buf_len = le32_to_cpu(req->MaxOutputResponse);
> >         out_buf_len = min(KSMBD_IPC_MAX_PAYLOAD, out_buf_len);
> > +       in_buf_len = le32_to_cpu(req->InputCount);
>
> Do you check if you have these many bytes remaining in the buffer?
>
> Also earlier in this function, where you assign req.
> If this is not a component in a compound, then you assign req =
> work->request_buf
> which starts with 4 bytes for the length and the smb2_hdr starts at
> offset 4, right?
>
> But if the ioctl is inside a compound, you assign req = ksmbd_req_buf_next()
> which just returns the offset to wherever NextCommand is?
> There are two problems here.
> Now req points to something where teh smb2 header starts at offset 0
> instead of 4.
> I unfortunately do not have any code to create Create/Ioctl/Close
> compounds to test this,
> but it looks like this is a problem.
>
> The second is that there is no check I can see that we validate that
> req now points to valid data,
> which means that when we dereference req just a few lines later
> (req->VolatileFileId)
> we might read random data beyond the end of request_buf   or we might oops.
>
>
> The same might be an issue in other functions as well.
>
>
> >
> >         switch (cnt_code) {
> >         case FSCTL_DFS_GET_REFERRALS:
> > @@ -7465,9 +7474,16 @@ int smb2_ioctl(struct ksmbd_work *work)
> >                         goto out;
> >                 }
> >
> > +               if (in_buf_len < sizeof(struct validate_negotiate_info_req))
> > +                       return -EINVAL;
> > +
> > +               if (out_buf_len < sizeof(struct validate_negotiate_info_rsp))
> > +                       return -EINVAL;
> > +
> >                 ret = fsctl_validate_negotiate_info(conn,
> >                         (struct validate_negotiate_info_req *)&req->Buffer[0],
> > -                       (struct validate_negotiate_info_rsp *)&rsp->Buffer[0]);
> > +                       (struct validate_negotiate_info_rsp *)&rsp->Buffer[0],
> > +                       in_buf_len);
> >                 if (ret < 0)
> >                         goto out;
> >
> > @@ -7476,7 +7492,7 @@ int smb2_ioctl(struct ksmbd_work *work)
> >                 rsp->VolatileFileId = cpu_to_le64(SMB2_NO_FID);
> >                 break;
> >         case FSCTL_QUERY_NETWORK_INTERFACE_INFO:
> > -               nbytes = fsctl_query_iface_info_ioctl(conn, req, rsp);
> > +               nbytes = fsctl_query_iface_info_ioctl(conn, rsp, out_buf_len);
> >                 if (nbytes < 0)
> >                         goto out;
> >                 break;
> > @@ -7503,15 +7519,33 @@ int smb2_ioctl(struct ksmbd_work *work)
> >                         goto out;
> >                 }
> >
> > +               if (in_buf_len < sizeof(struct copychunk_ioctl_req)) {
> > +                       ret = -EINVAL;
> > +                       goto out;
> > +               }
> > +
> >                 if (out_buf_len < sizeof(struct copychunk_ioctl_rsp)) {
> >                         ret = -EINVAL;
> >                         goto out;
> >                 }
> >
> >                 nbytes = sizeof(struct copychunk_ioctl_rsp);
> > -               fsctl_copychunk(work, req, rsp);
> > +               rsp->VolatileFileId = req->VolatileFileId;
> > +               rsp->PersistentFileId = req->PersistentFileId;
> > +               fsctl_copychunk(work,
> > +                               (struct copychunk_ioctl_req *)&req->Buffer[0],
> > +                               le32_to_cpu(req->CntCode),
> > +                               le32_to_cpu(req->InputCount),
> > +                               le64_to_cpu(req->VolatileFileId),
> > +                               le64_to_cpu(req->PersistentFileId),
> > +                               rsp);
> >                 break;
> >         case FSCTL_SET_SPARSE:
> > +               if (in_buf_len < sizeof(struct file_sparse)) {
> > +                       ret = -EINVAL;
> > +                       goto out;
> > +               }
> > +
> >                 ret = fsctl_set_sparse(work, id,
> >                                        (struct file_sparse *)&req->Buffer[0]);
> >                 if (ret < 0)
> > @@ -7530,6 +7564,11 @@ int smb2_ioctl(struct ksmbd_work *work)
> >                         goto out;
> >                 }
> >
> > +               if (in_buf_len < sizeof(struct file_zero_data_information)) {
> > +                       ret = -EINVAL;
> > +                       goto out;
> > +               }
> > +
> >                 zero_data =
> >                         (struct file_zero_data_information *)&req->Buffer[0];
> >
> > @@ -7549,6 +7588,11 @@ int smb2_ioctl(struct ksmbd_work *work)
> >                 break;
> >         }
> >         case FSCTL_QUERY_ALLOCATED_RANGES:
> > +               if (in_buf_len < sizeof(struct file_allocated_range_buffer)) {
> > +                       ret = -EINVAL;
> > +                       goto out;
> > +               }
> > +
> >                 ret = fsctl_query_allocated_ranges(work, id,
> >                         (struct file_allocated_range_buffer *)&req->Buffer[0],
> >                         (struct file_allocated_range_buffer *)&rsp->Buffer[0],
> > @@ -7589,6 +7633,11 @@ int smb2_ioctl(struct ksmbd_work *work)
> >                 struct duplicate_extents_to_file *dup_ext;
> >                 loff_t src_off, dst_off, length, cloned;
> >
> > +               if (in_buf_len < sizeof(struct duplicate_extents_to_file)) {
> > +                       ret = -EINVAL;
> > +                       goto out;
> > +               }
> > +
> >                 dup_ext = (struct duplicate_extents_to_file *)&req->Buffer[0];
> >
> >                 fp_in = ksmbd_lookup_fd_slow(work, dup_ext->VolatileFileHandle,
> > --
> > 2.25.1
> >

  reply	other threads:[~2021-09-22  4:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-22  2:28 Namjae Jeon
2021-09-22  3:48 ` ronnie sahlberg
2021-09-22  4:08   ` ronnie sahlberg [this message]
2021-09-22  4:13     ` Namjae Jeon
2021-09-23 15:02       ` Tom Talpey
2021-09-23 19:04         ` Namjae Jeon

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