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[NET]: Fix incorrect sg_mark_end() calls. 

This fixes scatterlist corruptions added by

	commit 68e3f5dd4d
	[CRYPTO] users: Fix up scatterlist conversion errors

The issue is that the code calls sg_mark_end() which clobbers the
sg_page() pointer of the final scatterlist entry.

The first part fo the fix makes skb_to_sgvec() do __sg_mark_end().

After considering all skb_to_sgvec() call sites the most correct
solution is to call __sg_mark_end() in skb_to_sgvec() since that is
what all of the callers would end up doing anyways.

I suspect this might have fixed some problems in virtio_net which is
the sole non-crypto user of skb_to_sgvec().

Other similar sg_mark_end() cases were converted over to
__sg_mark_end() as well.

Arguably sg_mark_end() is a poorly named function because it doesn't
just "mark", it clears out the page pointer as a side effect, which is
what led to these bugs in the first place.

The one remaining plain sg_mark_end() call is in scsi_alloc_sgtable()
and arguably it could be converted to __sg_mark_end() if only so that
we can delete this confusing interface from linux/scatterlist.h

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2007-10-30 21:29:29 -07:00
parent 07afa04025
commit 51c739d1f4
7 changed files with 37 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
net/core/skbuff.c
View File

@ -2028,8 +2028,8 @@ void __init skb_init(void)
* Fill the specified scatter-gather list with mappings/pointers into a
* region of the buffer space attached to a socket buffer.
*/
int
skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
static int
__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
{
int start = skb_headlen(skb);
int i, copy = start - offset;
@ -2078,7 +2078,8 @@ skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
elt += skb_to_sgvec(list, sg+elt, offset - start, copy);
elt += __skb_to_sgvec(list, sg+elt, offset - start,
copy);
if ((len -= copy) == 0)
return elt;
offset += copy;
@ -2090,6 +2091,15 @@ skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
return elt;
}
int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
{
int nsg = __skb_to_sgvec(skb, sg, offset, len);
__sg_mark_end(&sg[nsg - 1]);
return nsg;
}
/**
* skb_cow_data - Check that a socket buffer's data buffers are writable
* @skb: The socket buffer to check.

12
net/ipv4/esp4.c
View File

@ -111,9 +111,10 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
goto unlock;
}
sg_init_table(sg, nfrags);
sg_mark_end(sg, skb_to_sgvec(skb, sg, esph->enc_data +
esp->conf.ivlen -
skb->data, clen));
skb_to_sgvec(skb, sg,
esph->enc_data +
esp->conf.ivlen -
skb->data, clen);
err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);
@ -205,8 +206,9 @@ static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
goto out;
}
sg_init_table(sg, nfrags);
sg_mark_end(sg, skb_to_sgvec(skb, sg, sizeof(*esph) + esp->conf.ivlen,
elen));
skb_to_sgvec(skb, sg,
sizeof(*esph) + esp->conf.ivlen,
elen);
err = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);

2
net/ipv4/tcp_ipv4.c
View File

@ -1083,7 +1083,7 @@ static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
sg_set_buf(&sg[block++], key->key, key->keylen);
nbytes += key->keylen;
sg_mark_end(sg, block);
__sg_mark_end(&sg[block - 1]);
/* Now store the Hash into the packet */
err = crypto_hash_init(desc);

13
net/ipv6/esp6.c
View File

@ -110,9 +110,10 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
goto unlock;
}
sg_init_table(sg, nfrags);
sg_mark_end(sg, skb_to_sgvec(skb, sg, esph->enc_data +
esp->conf.ivlen -
skb->data, clen));
skb_to_sgvec(skb, sg,
esph->enc_data +
esp->conf.ivlen -
skb->data, clen);
err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);
@ -209,9 +210,9 @@ static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
}
}
sg_init_table(sg, nfrags);
sg_mark_end(sg, skb_to_sgvec(skb, sg,
sizeof(*esph) + esp->conf.ivlen,
elen));
skb_to_sgvec(skb, sg,
sizeof(*esph) + esp->conf.ivlen,
elen);
ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);

2
net/ipv6/tcp_ipv6.c
View File

@ -781,7 +781,7 @@ static int tcp_v6_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
sg_set_buf(&sg[block++], key->key, key->keylen);
nbytes += key->keylen;
sg_mark_end(sg, block);
__sg_mark_end(&sg[block - 1]);
/* Now store the hash into the packet */
err = crypto_hash_init(desc);

9
net/rxrpc/rxkad.c
View File

@ -237,7 +237,8 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
len = data_size + call->conn->size_align - 1;
len &= ~(call->conn->size_align - 1);
sg_init_table(sg, skb_to_sgvec(skb, sg, 0, len));
sg_init_table(sg, nsg);
skb_to_sgvec(skb, sg, 0, len);
crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
_leave(" = 0");
@ -344,7 +345,7 @@ static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
goto nomem;
sg_init_table(sg, nsg);
sg_mark_end(sg, skb_to_sgvec(skb, sg, 0, 8));
skb_to_sgvec(skb, sg, 0, 8);
/* start the decryption afresh */
memset(&iv, 0, sizeof(iv));
@ -426,7 +427,7 @@ static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
}
sg_init_table(sg, nsg);
sg_mark_end(sg, skb_to_sgvec(skb, sg, 0, skb->len));
skb_to_sgvec(skb, sg, 0, skb->len);
/* decrypt from the session key */
payload = call->conn->key->payload.data;
@ -701,7 +702,7 @@ static void rxkad_sg_set_buf2(struct scatterlist sg[2],
nsg++;
}
sg_mark_end(sg, nsg);
__sg_mark_end(&sg[nsg - 1]);
ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
}

6
net/sunrpc/auth_gss/gss_krb5_crypto.c
View File

@ -211,8 +211,8 @@ encryptor(struct scatterlist *sg, void *data)
if (thislen == 0)
return 0;
sg_mark_end(desc->infrags, desc->fragno);
sg_mark_end(desc->outfrags, desc->fragno);
__sg_mark_end(&desc->infrags[desc->fragno - 1]);
__sg_mark_end(&desc->outfrags[desc->fragno - 1]);
ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
desc->infrags, thislen);
@ -293,7 +293,7 @@ decryptor(struct scatterlist *sg, void *data)
if (thislen == 0)
return 0;
sg_mark_end(desc->frags, desc->fragno);
__sg_mark_end(&desc->frags[desc->fragno - 1]);
ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
desc->frags, thislen);