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From: Steve French <smfrench@gmail.com>
To: Paulo Alcantara <pc@cjr.nz>
Cc: "Aurélien Aptel" <aaptel@suse.com>,
	CIFS <linux-cifs@vger.kernel.org>,
	"ronnie sahlberg" <ronniesahlberg@gmail.com>
Subject: Re: [PATCH] cifs: missing null pointer check in cifs_mount
Date: Wed, 23 Jun 2021 19:34:08 -0500	[thread overview]
Message-ID: <CAH2r5mspWoea04K3Veuy9b-4k_TOLvuA13Xxnc8o0c=8g8zJrg@mail.gmail.com> (raw)
In-Reply-To: <B3F6DE12-CA6D-47BD-9383-B4BD2F73FCBC@cjr.nz>

[-- Attachment #1: Type: text/plain, Size: 883 bytes --]

updated patch attached with Aurelien's suggestion.

On Wed, Jun 23, 2021 at 7:17 AM Paulo Alcantara <pc@cjr.nz> wrote:
>
> Agreed.
>
> On June 23, 2021 8:48:24 AM GMT-03:00, "Aurélien Aptel" <aaptel@suse.com> wrote:
> >Steve French <smfrench@gmail.com> writes:
> >> We weren't checking if tcon is null before setting dfs path,
> >> although we check for null tcon in an earlier assignment statement.
> >
> >If tcon is NULL there is no point in continuing in that function, we
> >should have exited earlier.
> >
> >If tcon is NULL it means mount_get_conns() failed so presumably rc will
> >be != 0 and we would goto error.
> >
> >I don't think this is needed. We could change the existing check after
> >the loop to this you really want to be safe:
> >
> >       if (rc || !tcon)
> >               goto error;
> >
> >
> >Cheers,



-- 
Thanks,

Steve

[-- Attachment #2: 0001-cifs-missing-null-pointer-check-in-cifs_mount.patch --]
[-- Type: text/x-patch, Size: 899 bytes --]

From 162004a2f7ef5c77600e364dc4e9315b0e6ca386 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Wed, 23 Jun 2021 19:32:24 -0500
Subject: [PATCH] cifs: missing null pointer check in cifs_mount

We weren't checking if tcon is null before setting dfs path,
although we check for null tcon in an earlier assignment statement.

Addresses-Coverity: 1476411 ("Dereference after null check")
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/connect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 8d95607a9312..c8079376d294 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3451,7 +3451,7 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
 			rc = -ELOOP;
 	} while (rc == -EREMOTE);
 
-	if (rc)
+	if (rc || !tcon)
 		goto error;
 
 	kfree(ref_path);
-- 
2.30.2


      reply	other threads:[~2021-06-24  0:34 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-23  1:17 Steve French
2021-06-23 11:48 ` Aurélien Aptel
2021-06-23 12:17   ` Paulo Alcantara
2021-06-24  0:34     ` Steve French [this message]

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