Fix attached. Tentatively merged into cifs-2.6.git for-next pending
review and the usual "buildbot" automated regression testing
On Fri, Sep 13, 2019 at 12:09 PM Pavel Shilovsky via samba-technical
<samba-technical@xxxxxxxxxxxxxxx> wrote:
>
> Yes, this is a bug.
>
> Steve, let's move
>
> + mid->callback(mid);
> +
> + cifs_mid_q_entry_release(mid);
>
> under ELSE {} block above.
>
> We should probably move
>
> + dw->server->lstrp = jiffies;
>
> before we looking for a mid.
>
> --
> Best regards,
> Pavel Shilovsky
>
> пт, 13 сент. 2019 г. в 06:47, Dan Carpenter <dan.carpenter@xxxxxxxxxx>:
> >
> > tree: git://git.samba.org/sfrench/cifs-2.6.git for-next
> > head: 5fc321fb644fc787710353be11129edadd313f3a
> > commit: a091c5f67c994d154e8faf95ab774644be2f4dd7 [24/31] smb3: allow parallelizing decryption of reads
> >
> > If you fix the issue, kindly add following tag
> > Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> >
> > New smatch warnings:
> > fs/cifs/smb2ops.c:4056 smb2_decrypt_offload() error: we previously assumed 'mid' could be null (see line 4045)
> >
> > git remote add cifs git://git.samba.org/sfrench/cifs-2.6.git
> > git remote update cifs
> > git checkout a091c5f67c994d154e8faf95ab774644be2f4dd7
> > vim +/mid +4056 fs/cifs/smb2ops.c
> >
> > a091c5f67c994d Steve French 2019-09-07 4030 static void smb2_decrypt_offload(struct work_struct *work)
> > a091c5f67c994d Steve French 2019-09-07 4031 {
> > a091c5f67c994d Steve French 2019-09-07 4032 struct smb2_decrypt_work *dw = container_of(work,
> > a091c5f67c994d Steve French 2019-09-07 4033 struct smb2_decrypt_work, decrypt);
> > a091c5f67c994d Steve French 2019-09-07 4034 int i, rc;
> > a091c5f67c994d Steve French 2019-09-07 4035 struct mid_q_entry *mid;
> > a091c5f67c994d Steve French 2019-09-07 4036
> > a091c5f67c994d Steve French 2019-09-07 4037 rc = decrypt_raw_data(dw->server, dw->buf, dw->server->vals->read_rsp_size,
> > a091c5f67c994d Steve French 2019-09-07 4038 dw->ppages, dw->npages, dw->len);
> > a091c5f67c994d Steve French 2019-09-07 4039 if (rc) {
> > a091c5f67c994d Steve French 2019-09-07 4040 cifs_dbg(VFS, "error decrypting rc=%d\n", rc);
> > a091c5f67c994d Steve French 2019-09-07 4041 goto free_pages;
> > a091c5f67c994d Steve French 2019-09-07 4042 }
> > a091c5f67c994d Steve French 2019-09-07 4043
> > a091c5f67c994d Steve French 2019-09-07 4044 mid = smb2_find_mid(dw->server, dw->buf);
> > a091c5f67c994d Steve French 2019-09-07 @4045 if (mid == NULL)
> > a091c5f67c994d Steve French 2019-09-07 4046 cifs_dbg(FYI, "mid not found\n");
> >
> > Return here?
> >
> > a091c5f67c994d Steve French 2019-09-07 4047 else {
> > a091c5f67c994d Steve French 2019-09-07 4048 mid->decrypted = true;
> > a091c5f67c994d Steve French 2019-09-07 4049 rc = handle_read_data(dw->server, mid, dw->buf,
> > a091c5f67c994d Steve French 2019-09-07 4050 dw->server->vals->read_rsp_size,
> > a091c5f67c994d Steve French 2019-09-07 4051 dw->ppages, dw->npages, dw->len);
> > a091c5f67c994d Steve French 2019-09-07 4052 }
> > a091c5f67c994d Steve French 2019-09-07 4053
> > a091c5f67c994d Steve French 2019-09-07 4054 dw->server->lstrp = jiffies;
> > a091c5f67c994d Steve French 2019-09-07 4055
> > a091c5f67c994d Steve French 2019-09-07 @4056 mid->callback(mid);
> > ^^^^^^^^^^^^^
> > Potential NULL derference.
> >
> > a091c5f67c994d Steve French 2019-09-07 4057
> > a091c5f67c994d Steve French 2019-09-07 4058 cifs_mid_q_entry_release(mid);
> > a091c5f67c994d Steve French 2019-09-07 4059
> > a091c5f67c994d Steve French 2019-09-07 4060 free_pages:
> > a091c5f67c994d Steve French 2019-09-07 4061 for (i = dw->npages-1; i >= 0; i--)
> > a091c5f67c994d Steve French 2019-09-07 4062 put_page(dw->ppages[i]);
> > a091c5f67c994d Steve French 2019-09-07 4063
> > a091c5f67c994d Steve French 2019-09-07 4064 kfree(dw->ppages);
> > a091c5f67c994d Steve French 2019-09-07 4065 cifs_small_buf_release(dw->buf);
> > a091c5f67c994d Steve French 2019-09-07 4066 }
> >
> > ---
> > 0-DAY kernel test infrastructure Open Source Technology Center
> > https://lists.01.org/pipermail/kbuild-all Intel Corporation
>
--
Thanks,
Steve
From 9b6ecf32499b32259ea306fc3e150ce2337a8b7b Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Fri, 13 Sep 2019 16:47:31 -0500
Subject: [PATCH] smb3: fix potential null dereference in decrypt offload
commit a091c5f67c99 ("smb3: allow parallelizing decryption of reads")
had a potential null dereference
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Suggested-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/cifs/smb2ops.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 5776d7b0a97e..eaed18061314 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4055,6 +4055,7 @@ static void smb2_decrypt_offload(struct work_struct *work)
goto free_pages;
}
+ dw->server->lstrp = jiffies;
mid = smb2_find_mid(dw->server, dw->buf);
if (mid == NULL)
cifs_dbg(FYI, "mid not found\n");
@@ -4063,14 +4064,10 @@ static void smb2_decrypt_offload(struct work_struct *work)
rc = handle_read_data(dw->server, mid, dw->buf,
dw->server->vals->read_rsp_size,
dw->ppages, dw->npages, dw->len);
+ mid->callback(mid);
+ cifs_mid_q_entry_release(mid);
}
- dw->server->lstrp = jiffies;
-
- mid->callback(mid);
-
- cifs_mid_q_entry_release(mid);
-
free_pages:
for (i = dw->npages-1; i >= 0; i--)
put_page(dw->ppages[i]);
--
2.20.1
