[PATCH] cifs: revalidate mapping when we open files for SMB1 POSIX

[PATCH] cifs: revalidate mapping when we open files for SMB1 POSIX

[Ronnie Sahlberg]

RHBZ: 1933527

Under SMB1 + POSIX, if an inode is reused on a server after we have read and
cached a part of a file, when we then open the new file with the
re-cycled inode there is a chance that we may serve the old data out of cache
to the application.
This only happens for SMB1 (deprecated) and when posix are used.
The simplest solution to avoid this race is to force a revalidate
on smb1-posix open.

 Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 26de4329d161..042e24aad410 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -165,6 +165,7 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
 			goto posix_open_ret;
 		}
 	} else {
+		cifs_revalidate_mapping(*pinode);
 		cifs_fattr_to_inode(*pinode, &fattr);
 	}
 
-- 
2.29.2

Re: [PATCH] cifs: revalidate mapping when we open files for SMB1 POSIX

[Paulo Alcantara]

Ronnie Sahlberg <lsahlber@redhat.com> writes:

> RHBZ: 1933527
>
> Under SMB1 + POSIX, if an inode is reused on a server after we have read and
> cached a part of a file, when we then open the new file with the
> re-cycled inode there is a chance that we may serve the old data out of cache
> to the application.
> This only happens for SMB1 (deprecated) and when posix are used.
> The simplest solution to avoid this race is to force a revalidate
> on smb1-posix open.
>
>  Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
>  fs/cifs/file.c | 1 +
>  1 file changed, 1 insertion(+)

Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>

Re: [PATCH] cifs: revalidate mapping when we open files for SMB1 POSIX

[Steve French]

merged into cifs-2.6.git for-next

On Thu, Mar 25, 2021 at 10:34 AM Paulo Alcantara <pc@cjr.nz> wrote:
>
> Ronnie Sahlberg <lsahlber@redhat.com> writes:
>
> > RHBZ: 1933527
> >
> > Under SMB1 + POSIX, if an inode is reused on a server after we have read and
> > cached a part of a file, when we then open the new file with the
> > re-cycled inode there is a chance that we may serve the old data out of cache
> > to the application.
> > This only happens for SMB1 (deprecated) and when posix are used.
> > The simplest solution to avoid this race is to force a revalidate
> > on smb1-posix open.
> >
> >  Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> > ---
> >  fs/cifs/file.c | 1 +
> >  1 file changed, 1 insertion(+)
>
> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>



-- 
Thanks,

Steve

[PATCH] cifs: revalidate mapping when we open files for SMB1 POSIX

[Ronnie Sahlberg]

RHBZ: 1933527

We have seen read cache surviving across close to open under
SMB1 POSIX.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 26de4329d161..042e24aad410 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -165,6 +165,7 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
 			goto posix_open_ret;
 		}
 	} else {
+		cifs_revalidate_mapping(*pinode);
 		cifs_fattr_to_inode(*pinode, &fattr);
 	}
 
-- 
2.29.2

[PATCH] cifs: revalidate mapping when we open files for SMB1 POSIX

[Ronnie Sahlberg]

From: root <root@localhost.localdomain>

RHBZ: 1933527

We have seen read cashe surviving across close to open under
SMB1 POSIX.

Signed-off-by: root <root@localhost.localdomain>
---
 fs/cifs/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 26de4329d161..042e24aad410 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -165,6 +165,7 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
 			goto posix_open_ret;
 		}
 	} else {
+		cifs_revalidate_mapping(*pinode);
 		cifs_fattr_to_inode(*pinode, &fattr);
 	}
 
-- 
2.29.2