вт, 7 мая 2019 г. в 09:13, Steve French via samba-technical
<samba-technical@xxxxxxxxxxxxxxx>:
>
> merged into cifs-2.6.git for-next
>
> On Tue, May 7, 2019 at 10:17 AM Christoph Probst via samba-technical
> <samba-technical@xxxxxxxxxxxxxxx> wrote:
> >
> > Change strcat to strncpy in the "None" case to fix a buffer overflow
> > when cinode->oplock is reset to 0 by another thread accessing the same
> > cinode. It is never valid to append "None" to any other message.
> >
> > Consolidate multiple writes to cinode->oplock to reduce raciness.
> >
> > Signed-off-by: Christoph Probst <kernel@xxxxxxxxx>
> > ---
> > fs/cifs/smb2ops.c | 14 ++++++++------
> > 1 file changed, 8 insertions(+), 6 deletions(-)
> >
> > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> > index c36ff0d..aa61dcf 100644
> > --- a/fs/cifs/smb2ops.c
> > +++ b/fs/cifs/smb2ops.c
> > @@ -2917,26 +2917,28 @@ smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
> > unsigned int epoch, bool *purge_cache)
> > {
> > char message[5] = {0};
> > + unsigned int new_oplock = 0;
> >
> > oplock &= 0xFF;
> > if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
> > return;
> >
> > - cinode->oplock = 0;
> > if (oplock & SMB2_LEASE_READ_CACHING_HE) {
> > - cinode->oplock |= CIFS_CACHE_READ_FLG;
> > + new_oplock |= CIFS_CACHE_READ_FLG;
> > strcat(message, "R");
> > }
> > if (oplock & SMB2_LEASE_HANDLE_CACHING_HE) {
> > - cinode->oplock |= CIFS_CACHE_HANDLE_FLG;
> > + new_oplock |= CIFS_CACHE_HANDLE_FLG;
> > strcat(message, "H");
> > }
> > if (oplock & SMB2_LEASE_WRITE_CACHING_HE) {
> > - cinode->oplock |= CIFS_CACHE_WRITE_FLG;
> > + new_oplock |= CIFS_CACHE_WRITE_FLG;
> > strcat(message, "W");
> > }
> > - if (!cinode->oplock)
> > - strcat(message, "None");
> > + if (!new_oplock)
> > + strncpy(message, "None", sizeof(message));
> > +
> > + cinode->oplock = new_oplock;
> > cifs_dbg(FYI, "%s Lease granted on inode %p\n", message,
> > &cinode->vfs_inode);
> > }
> > --
> > 2.1.4
> >
> >
>
Thanks for cleaning it up!
Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
--
Best regards,
Pavel Shilovsky
