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CVE-2014-0131: skbuff: use-after-free during segmentation with zerocopy (rhbz 1074589 1079006)

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This commit is contained in:
Josh Boyer 2014-03-20 14:14:05 -04:00
parent 4e4ade3de3
commit 705e48c868
2 changed files with 456 additions and 0 deletions
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7
kernel.spec
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@ -812,6 +812,9 @@ Patch25045: netfilter-nf_conntrack_dccp-fix-skb_header_pointer-A.patch
#rhbz 1078894
Patch25046: mm-readahead.c-fix-do_readahead-for-no-readpage-s.patch
#CVE-2014-0131 rhbz 1074589 1079006
Patch25048: skbuff-zero-copy.patch
# END OF PATCH DEFINITIONS
%endif
@ -1570,6 +1573,9 @@ ApplyPatch netfilter-nf_conntrack_dccp-fix-skb_header_pointer-A.patch
#rhbz 1078894
ApplyPatch mm-readahead.c-fix-do_readahead-for-no-readpage-s.patch
#CVE-2014-0131 rhbz 1074589 1079006
ApplyPatch skbuff-zero-copy.patch
# END OF PATCH APPLICATIONS
%endif
@ -2383,6 +2389,7 @@ fi
%changelog
* Thu Mar 20 2014 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2014-0131: skbuff: use-after-free during segmentation with zerocopy (rhbz 1074589 1079006)
- Fix readahead semantics on pipes and sockets (rhbz 1078894)
* Mon Mar 17 2014 Josh Boyer <jwboyer@fedoraproject.org>

449
skbuff-zero-copy.patch Normal file
View File

@ -0,0 +1,449 @@
Bugzilla: 1079006
Upstream-status: 3.14 and queued for stable
From 8cb19905e9287a93ce7c2cbbdf742a060b00e219 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Mon, 10 Mar 2014 18:29:04 +0200
Subject: [PATCH 1/5] skbuff: skb_segment: s/frag/nskb_frag/
frag points at nskb, so name it appropriately
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/skbuff.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 5d6236d..60e8cd7 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2876,7 +2876,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
do {
struct sk_buff *nskb;
- skb_frag_t *frag;
+ skb_frag_t *nskb_frag;
int hsize;
int size;
@@ -2969,7 +2969,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
continue;
}
- frag = skb_shinfo(nskb)->frags;
+ nskb_frag = skb_shinfo(nskb)->frags;
skb_copy_from_linear_data_offset(skb, offset,
skb_put(nskb, hsize), hsize);
@@ -2997,13 +2997,13 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
goto err;
}
- *frag = *skb_frag;
- __skb_frag_ref(frag);
- size = skb_frag_size(frag);
+ *nskb_frag = *skb_frag;
+ __skb_frag_ref(nskb_frag);
+ size = skb_frag_size(nskb_frag);
if (pos < offset) {
- frag->page_offset += offset - pos;
- skb_frag_size_sub(frag, offset - pos);
+ nskb_frag->page_offset += offset - pos;
+ skb_frag_size_sub(nskb_frag, offset - pos);
}
skb_shinfo(nskb)->nr_frags++;
@@ -3013,11 +3013,11 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
skb_frag++;
pos += size;
} else {
- skb_frag_size_sub(frag, pos + size - (offset + len));
+ skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
goto skip_fraglist;
}
- frag++;
+ nskb_frag++;
}
skip_fraglist:
--
1.8.5.3
From 4e1beba12d094c6c761ba5c49032b9b9e46380e8 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Mon, 10 Mar 2014 18:29:14 +0200
Subject: [PATCH 2/5] skbuff: skb_segment: s/skb_frag/frag/
skb_frag can in fact point at either skb
or fskb so rename it generally "frag".
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/skbuff.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 60e8cd7..d788a98 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2850,7 +2850,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
struct sk_buff *segs = NULL;
struct sk_buff *tail = NULL;
struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
- skb_frag_t *skb_frag = skb_shinfo(skb)->frags;
+ skb_frag_t *frag = skb_shinfo(skb)->frags;
unsigned int mss = skb_shinfo(skb)->gso_size;
unsigned int doffset = skb->data - skb_mac_header(skb);
unsigned int offset = doffset;
@@ -2896,19 +2896,19 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
i = 0;
nfrags = skb_shinfo(fskb)->nr_frags;
- skb_frag = skb_shinfo(fskb)->frags;
+ frag = skb_shinfo(fskb)->frags;
pos += skb_headlen(fskb);
while (pos < offset + len) {
BUG_ON(i >= nfrags);
- size = skb_frag_size(skb_frag);
+ size = skb_frag_size(frag);
if (pos + size > offset + len)
break;
i++;
pos += size;
- skb_frag++;
+ frag++;
}
nskb = skb_clone(fskb, GFP_ATOMIC);
@@ -2982,7 +2982,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
i = 0;
nfrags = skb_shinfo(fskb)->nr_frags;
- skb_frag = skb_shinfo(fskb)->frags;
+ frag = skb_shinfo(fskb)->frags;
BUG_ON(!nfrags);
@@ -2997,7 +2997,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
goto err;
}
- *nskb_frag = *skb_frag;
+ *nskb_frag = *frag;
__skb_frag_ref(nskb_frag);
size = skb_frag_size(nskb_frag);
@@ -3010,7 +3010,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
if (pos + size <= offset + len) {
i++;
- skb_frag++;
+ frag++;
pos += size;
} else {
skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
--
1.8.5.3
From df5771ffefb13f8af5392bd54fd7e2b596a3a357 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Mon, 10 Mar 2014 18:29:19 +0200
Subject: [PATCH 3/5] skbuff: skb_segment: s/skb/head_skb/
rename local variable to make it easier to tell at a glance that we are
dealing with a head skb.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/skbuff.c | 46 ++++++++++++++++++++++++----------------------
1 file changed, 24 insertions(+), 22 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d788a98..fdc065d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2838,41 +2838,42 @@ EXPORT_SYMBOL_GPL(skb_pull_rcsum);
/**
* skb_segment - Perform protocol segmentation on skb.
- * @skb: buffer to segment
+ * @head_skb: buffer to segment
* @features: features for the output path (see dev->features)
*
* This function performs segmentation on the given skb. It returns
* a pointer to the first in a list of new skbs for the segments.
* In case of error it returns ERR_PTR(err).
*/
-struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
+struct sk_buff *skb_segment(struct sk_buff *head_skb,
+ netdev_features_t features)
{
struct sk_buff *segs = NULL;
struct sk_buff *tail = NULL;
- struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
- skb_frag_t *frag = skb_shinfo(skb)->frags;
- unsigned int mss = skb_shinfo(skb)->gso_size;
- unsigned int doffset = skb->data - skb_mac_header(skb);
+ struct sk_buff *fskb = skb_shinfo(head_skb)->frag_list;
+ skb_frag_t *frag = skb_shinfo(head_skb)->frags;
+ unsigned int mss = skb_shinfo(head_skb)->gso_size;
+ unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
unsigned int offset = doffset;
- unsigned int tnl_hlen = skb_tnl_header_len(skb);
+ unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
unsigned int headroom;
unsigned int len;
__be16 proto;
bool csum;
int sg = !!(features & NETIF_F_SG);
- int nfrags = skb_shinfo(skb)->nr_frags;
+ int nfrags = skb_shinfo(head_skb)->nr_frags;
int err = -ENOMEM;
int i = 0;
int pos;
- proto = skb_network_protocol(skb);
+ proto = skb_network_protocol(head_skb);
if (unlikely(!proto))
return ERR_PTR(-EINVAL);
csum = !!can_checksum_protocol(features, proto);
- __skb_push(skb, doffset);
- headroom = skb_headroom(skb);
- pos = skb_headlen(skb);
+ __skb_push(head_skb, doffset);
+ headroom = skb_headroom(head_skb);
+ pos = skb_headlen(head_skb);
do {
struct sk_buff *nskb;
@@ -2880,11 +2881,11 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
int hsize;
int size;
- len = skb->len - offset;
+ len = head_skb->len - offset;
if (len > mss)
len = mss;
- hsize = skb_headlen(skb) - offset;
+ hsize = skb_headlen(head_skb) - offset;
if (hsize < 0)
hsize = 0;
if (hsize > len || !sg)
@@ -2933,7 +2934,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
__skb_push(nskb, doffset);
} else {
nskb = __alloc_skb(hsize + doffset + headroom,
- GFP_ATOMIC, skb_alloc_rx_flag(skb),
+ GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
NUMA_NO_NODE);
if (unlikely(!nskb))
@@ -2949,12 +2950,12 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
segs = nskb;
tail = nskb;
- __copy_skb_header(nskb, skb);
- nskb->mac_len = skb->mac_len;
+ __copy_skb_header(nskb, head_skb);
+ nskb->mac_len = head_skb->mac_len;
skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
- skb_copy_from_linear_data_offset(skb, -tnl_hlen,
+ skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
nskb->data - tnl_hlen,
doffset + tnl_hlen);
@@ -2963,7 +2964,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
if (!sg) {
nskb->ip_summed = CHECKSUM_NONE;
- nskb->csum = skb_copy_and_csum_bits(skb, offset,
+ nskb->csum = skb_copy_and_csum_bits(head_skb, offset,
skb_put(nskb, len),
len, 0);
continue;
@@ -2971,10 +2972,11 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
nskb_frag = skb_shinfo(nskb)->frags;
- skb_copy_from_linear_data_offset(skb, offset,
+ skb_copy_from_linear_data_offset(head_skb, offset,
skb_put(nskb, hsize), hsize);
- skb_shinfo(nskb)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
+ skb_shinfo(nskb)->tx_flags = skb_shinfo(head_skb)->tx_flags &
+ SKBTX_SHARED_FRAG;
while (pos < offset + len) {
if (i >= nfrags) {
@@ -3031,7 +3033,7 @@ perform_csum_check:
nskb->len - doffset, 0);
nskb->ip_summed = CHECKSUM_NONE;
}
- } while ((offset += len) < skb->len);
+ } while ((offset += len) < head_skb->len);
return segs;
--
1.8.5.3
From 1a4cedaf65491e66e1e55b8428c89209da729209 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Mon, 10 Mar 2014 19:27:59 +0200
Subject: [PATCH 4/5] skbuff: skb_segment: s/fskb/list_skb/
fskb is unrelated to frag: it's coming from
frag_list. Rename it list_skb to avoid confusion.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/skbuff.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index fdc065d..dc4f768 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2850,7 +2850,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
{
struct sk_buff *segs = NULL;
struct sk_buff *tail = NULL;
- struct sk_buff *fskb = skb_shinfo(head_skb)->frag_list;
+ struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
skb_frag_t *frag = skb_shinfo(head_skb)->frags;
unsigned int mss = skb_shinfo(head_skb)->gso_size;
unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
@@ -2891,14 +2891,14 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
if (hsize > len || !sg)
hsize = len;
- if (!hsize && i >= nfrags && skb_headlen(fskb) &&
- (skb_headlen(fskb) == len || sg)) {
- BUG_ON(skb_headlen(fskb) > len);
+ if (!hsize && i >= nfrags && skb_headlen(list_skb) &&
+ (skb_headlen(list_skb) == len || sg)) {
+ BUG_ON(skb_headlen(list_skb) > len);
i = 0;
- nfrags = skb_shinfo(fskb)->nr_frags;
- frag = skb_shinfo(fskb)->frags;
- pos += skb_headlen(fskb);
+ nfrags = skb_shinfo(list_skb)->nr_frags;
+ frag = skb_shinfo(list_skb)->frags;
+ pos += skb_headlen(list_skb);
while (pos < offset + len) {
BUG_ON(i >= nfrags);
@@ -2912,8 +2912,8 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
frag++;
}
- nskb = skb_clone(fskb, GFP_ATOMIC);
- fskb = fskb->next;
+ nskb = skb_clone(list_skb, GFP_ATOMIC);
+ list_skb = list_skb->next;
if (unlikely(!nskb))
goto err;
@@ -2980,15 +2980,15 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
while (pos < offset + len) {
if (i >= nfrags) {
- BUG_ON(skb_headlen(fskb));
+ BUG_ON(skb_headlen(list_skb));
i = 0;
- nfrags = skb_shinfo(fskb)->nr_frags;
- frag = skb_shinfo(fskb)->frags;
+ nfrags = skb_shinfo(list_skb)->nr_frags;
+ frag = skb_shinfo(list_skb)->frags;
BUG_ON(!nfrags);
- fskb = fskb->next;
+ list_skb = list_skb->next;
}
if (unlikely(skb_shinfo(nskb)->nr_frags >=
--
1.8.5.3
From 1fd819ecb90cc9b822cd84d3056ddba315d3340f Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Mon, 10 Mar 2014 19:28:08 +0200
Subject: [PATCH 5/5] skbuff: skb_segment: orphan frags before copying
skb_segment copies frags around, so we need
to copy them carefully to avoid accessing
user memory after reporting completion to userspace
through a callback.
skb_segment doesn't normally happen on datapath:
TSO needs to be disabled - so disabling zero copy
in this case does not look like a big deal.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/skbuff.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index dc4f768..869c7af 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2854,6 +2854,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
skb_frag_t *frag = skb_shinfo(head_skb)->frags;
unsigned int mss = skb_shinfo(head_skb)->gso_size;
unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
+ struct sk_buff *frag_skb = head_skb;
unsigned int offset = doffset;
unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
unsigned int headroom;
@@ -2898,6 +2899,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
i = 0;
nfrags = skb_shinfo(list_skb)->nr_frags;
frag = skb_shinfo(list_skb)->frags;
+ frag_skb = list_skb;
pos += skb_headlen(list_skb);
while (pos < offset + len) {
@@ -2985,6 +2987,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
i = 0;
nfrags = skb_shinfo(list_skb)->nr_frags;
frag = skb_shinfo(list_skb)->frags;
+ frag_skb = list_skb;
BUG_ON(!nfrags);
@@ -2999,6 +3002,9 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
goto err;
}
+ if (unlikely(skb_orphan_frags(frag_skb, GFP_ATOMIC)))
+ goto err;
+
*nskb_frag = *frag;
__skb_frag_ref(nskb_frag);
size = skb_frag_size(nskb_frag);
--
1.8.5.3