On Fri, 14 Feb 2014 13:31:02 +0400 Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote: > SMB3 servers can respond with MaxTransactSize of more than 4M > that can cause a memory allocation error returned from kmalloc > in a lock codepath. Also the client doesn't support multicredit > requests now and allows buffer sizes of 65536 bytes only. Set > MaxTransactSize to this maximum supported value. > > Cc: stable@xxxxxxxxxxxxxxx # 3.7+ > Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx> > --- > fs/cifs/smb2glob.h | 3 +++ > fs/cifs/smb2ops.c | 14 ++++---------- > fs/cifs/smb2pdu.c | 4 +++- > 3 files changed, 10 insertions(+), 11 deletions(-) > > diff --git a/fs/cifs/smb2glob.h b/fs/cifs/smb2glob.h > index c383508..bc0bb9c 100644 > --- a/fs/cifs/smb2glob.h > +++ b/fs/cifs/smb2glob.h > @@ -57,4 +57,7 @@ > #define SMB2_CMACAES_SIZE (16) > #define SMB3_SIGNKEY_SIZE (16) > > +/* Maximum buffer size value we can send with 1 credit */ > +#define SMB2_MAX_BUFFER_SIZE 65536 > + > #endif /* _SMB2_GLOB_H */ > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c > index 757da3e..192f51a 100644 > --- a/fs/cifs/smb2ops.c > +++ b/fs/cifs/smb2ops.c > @@ -182,11 +182,8 @@ smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info) > /* start with specified wsize, or default */ > wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE; > wsize = min_t(unsigned int, wsize, server->max_write); > - /* > - * limit write size to 2 ** 16, because we don't support multicredit > - * requests now. > - */ > - wsize = min_t(unsigned int, wsize, 2 << 15); > + /* set it to the maximum buffer size value we can send with 1 credit */ > + wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE); > > return wsize; > } > @@ -200,11 +197,8 @@ smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *volume_info) > /* start with specified rsize, or default */ > rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE; > rsize = min_t(unsigned int, rsize, server->max_read); > - /* > - * limit write size to 2 ** 16, because we don't support multicredit > - * requests now. > - */ > - rsize = min_t(unsigned int, rsize, 2 << 15); > + /* set it to the maximum buffer size value we can send with 1 credit */ > + rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE); > > return rsize; > } > diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c > index 2013234..787e171 100644 > --- a/fs/cifs/smb2pdu.c > +++ b/fs/cifs/smb2pdu.c > @@ -413,7 +413,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses) > > /* SMB2 only has an extended negflavor */ > server->negflavor = CIFS_NEGFLAVOR_EXTENDED; > - server->maxBuf = le32_to_cpu(rsp->MaxTransactSize); > + /* set it to the maximum buffer size value we can send with 1 credit */ > + server->maxBuf = min_t(unsigned int, le32_to_cpu(rsp->MaxTransactSize), > + SMB2_MAX_BUFFER_SIZE); > server->max_read = le32_to_cpu(rsp->MaxReadSize); > server->max_write = le32_to_cpu(rsp->MaxWriteSize); > /* BB Do we need to validate the SecurityMode? */ Acked-by: Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
