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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2010-02-07 20:20:28 +0000
committerDavid S. Miller <davem@davemloft.net>2010-02-12 11:47:00 -0800
commit69a6a0b38a139ccceef32222108caca8a9b0b795 (patch)
tree04e24f2b012c14f33f5bc3d6f96f84056cf1fbbe /net/dccp
parent7455a76f170f794498d26081a5f15b797ef1a2aa (diff)
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dccp: allow probing of CCID-array length
This fixes a problem in the DCCP getsockopt() API: currently there is no way for a user to a priori know the number of built-in CCIDs, other than trying DCCP_SOCKOPT_AVAILABLE_CCIDS in a loop, incrementing the option length until EINVAL is no longer returned. This patch truncates the array to the user-provided length. No copy is made when the length is <= 0. Due to the length restriction in do_dccp_getsockopt() to sizeof(int), the minimum array length remains 4, which is a reasonable default (only 3 CCIDs, CCID-2..4, are currently defined). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp')
-rw-r--r--net/dccp/ccid.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c
index ff16e9df1969..49d27c556bec 100644
--- a/net/dccp/ccid.c
+++ b/net/dccp/ccid.c
@@ -63,14 +63,13 @@ int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
u8 *ccid_array, array_len;
int err = 0;
- if (len < ARRAY_SIZE(ccids))
- return -EINVAL;
-
if (ccid_get_builtin_ccids(&ccid_array, &array_len))
return -ENOBUFS;
- if (put_user(array_len, optlen) ||
- copy_to_user(optval, ccid_array, array_len))
+ if (put_user(array_len, optlen))
+ err = -EFAULT;
+ else if (len > 0 && copy_to_user(optval, ccid_array,
+ len > array_len ? array_len : len))
err = -EFAULT;
kfree(ccid_array);