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author | Matt Domsch <Matt_Domsch@dell.com> | 2005-11-08 09:40:47 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2005-11-08 09:40:47 -0800 |
commit | b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c (patch) | |
tree | 7ca8e019573362620638e14e32bb519770ee6945 /drivers/net/ppp_generic.c | |
parent | 6722e78c90054101e6797d5944cdc81af9897a0a (diff) | |
download | kernel_samsung_smdk4412-b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c.zip kernel_samsung_smdk4412-b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c.tar.gz kernel_samsung_smdk4412-b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c.tar.bz2 |
[PPP]: add PPP MPPE encryption module
From: Matt Domsch <Matt_Domsch@dell.com>
The patch below implements the Microsoft Point-to-Point Encryption method
as a PPP compressor/decompressor. This is necessary for Linux clients and
servers to interoperate with Microsoft Point-to-Point Tunneling Protocol
(PPTP) servers (either Microsoft PPTP servers or the poptop project) which
use MPPE to encrypt data when creating a VPN.
This patch differs from the kernel_ppp_mppe DKMS pacakge at
pptpclient.sourceforge.net by utilizing the kernel crypto routines rather
than providing its own SHA1 and arcfour implementations.
Minor changes to ppp_generic.c try to prevent a link from disabling
compression (in our case, the encryption) after it has started using
compression (encryption).
Feedback to <pptpclient-devel@lists.sourceforge.net> please.
Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>
Cc: James Cameron <james.cameron@hp.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ppp_generic.c')
-rw-r--r-- | drivers/net/ppp_generic.c | 88 |
1 files changed, 64 insertions, 24 deletions
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c index d3c9958..50430f7 100644 --- a/drivers/net/ppp_generic.c +++ b/drivers/net/ppp_generic.c @@ -137,13 +137,14 @@ struct ppp { /* * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC, - * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP. + * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP, + * SC_MUST_COMP * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR. * Bits in xstate: SC_COMP_RUN */ #define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \ |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \ - |SC_COMP_TCP|SC_REJ_COMP_TCP) + |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP) /* * Private data structure for each channel. @@ -1027,6 +1028,56 @@ ppp_xmit_process(struct ppp *ppp) ppp_xmit_unlock(ppp); } +static inline struct sk_buff * +pad_compress_skb(struct ppp *ppp, struct sk_buff *skb) +{ + struct sk_buff *new_skb; + int len; + int new_skb_size = ppp->dev->mtu + + ppp->xcomp->comp_extra + ppp->dev->hard_header_len; + int compressor_skb_size = ppp->dev->mtu + + ppp->xcomp->comp_extra + PPP_HDRLEN; + new_skb = alloc_skb(new_skb_size, GFP_ATOMIC); + if (!new_skb) { + if (net_ratelimit()) + printk(KERN_ERR "PPP: no memory (comp pkt)\n"); + return NULL; + } + if (ppp->dev->hard_header_len > PPP_HDRLEN) + skb_reserve(new_skb, + ppp->dev->hard_header_len - PPP_HDRLEN); + + /* compressor still expects A/C bytes in hdr */ + len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, + new_skb->data, skb->len + 2, + compressor_skb_size); + if (len > 0 && (ppp->flags & SC_CCP_UP)) { + kfree_skb(skb); + skb = new_skb; + skb_put(skb, len); + skb_pull(skb, 2); /* pull off A/C bytes */ + } else if (len == 0) { + /* didn't compress, or CCP not up yet */ + kfree_skb(new_skb); + new_skb = skb; + } else { + /* + * (len < 0) + * MPPE requires that we do not send unencrypted + * frames. The compressor will return -1 if we + * should drop the frame. We cannot simply test + * the compress_proto because MPPE and MPPC share + * the same number. + */ + if (net_ratelimit()) + printk(KERN_ERR "ppp: compressor dropped pkt\n"); + kfree_skb(skb); + kfree_skb(new_skb); + new_skb = NULL; + } + return new_skb; +} + /* * Compress and send a frame. * The caller should have locked the xmit path, @@ -1113,29 +1164,14 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb) /* try to do packet compression */ if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0 && proto != PPP_LCP && proto != PPP_CCP) { - new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len, - GFP_ATOMIC); - if (new_skb == 0) { - printk(KERN_ERR "PPP: no memory (comp pkt)\n"); + if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) { + if (net_ratelimit()) + printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n"); goto drop; } - if (ppp->dev->hard_header_len > PPP_HDRLEN) - skb_reserve(new_skb, - ppp->dev->hard_header_len - PPP_HDRLEN); - - /* compressor still expects A/C bytes in hdr */ - len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, - new_skb->data, skb->len + 2, - ppp->dev->mtu + PPP_HDRLEN); - if (len > 0 && (ppp->flags & SC_CCP_UP)) { - kfree_skb(skb); - skb = new_skb; - skb_put(skb, len); - skb_pull(skb, 2); /* pull off A/C bytes */ - } else { - /* didn't compress, or CCP not up yet */ - kfree_skb(new_skb); - } + skb = pad_compress_skb(ppp, skb); + if (!skb) + goto drop; } /* @@ -1155,7 +1191,8 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb) return; drop: - kfree_skb(skb); + if (skb) + kfree_skb(skb); ++ppp->stats.tx_errors; } @@ -1552,6 +1589,9 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb) && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0) skb = ppp_decompress_frame(ppp, skb); + if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR) + goto err; + proto = PPP_PROTO(skb); switch (proto) { case PPP_VJC_COMP: |