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authorMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>2023-01-23 14:59:33 -0300
committerJakub Kicinski <kuba@kernel.org>2023-01-24 18:32:33 -0800
commit458e279f861d3f61796894cd158b780765a1569f (patch)
treefbadfaa46ca1f4662b26eb3d92aaa81b22ecb1d1 /net/sctp
parentea4fdbaa2f7798cb25adbe4fd52ffc6356f097bb (diff)
sctp: fail if no bound addresses can be used for a given scope
Currently, if you bind the socket to something like: servaddr.sin6_family = AF_INET6; servaddr.sin6_port = htons(0); servaddr.sin6_scope_id = 0; inet_pton(AF_INET6, "::1", &servaddr.sin6_addr); And then request a connect to: connaddr.sin6_family = AF_INET6; connaddr.sin6_port = htons(20000); connaddr.sin6_scope_id = if_nametoindex("lo"); inet_pton(AF_INET6, "fe88::1", &connaddr.sin6_addr); What the stack does is: - bind the socket - create a new asoc - to handle the connect - copy the addresses that can be used for the given scope - try to connect But the copy returns 0 addresses, and the effect is that it ends up trying to connect as if the socket wasn't bound, which is not the desired behavior. This unexpected behavior also allows KASLR leaks through SCTP diag interface. The fix here then is, if when trying to copy the addresses that can be used for the scope used in connect() it returns 0 addresses, bail out. This is what TCP does with a similar reproducer. Reported-by: Pietro Borrello <borrello@diag.uniroma1.it> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Link: https://lore.kernel.org/r/9fcd182f1099f86c6661f3717f63712ddd1c676c.1674496737.git.marcelo.leitner@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/bind_addr.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
index 59e653b528b1..6b95d3ba8fe1 100644
--- a/net/sctp/bind_addr.c
+++ b/net/sctp/bind_addr.c
@@ -73,6 +73,12 @@ int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
}
}
+ /* If somehow no addresses were found that can be used with this
+ * scope, it's an error.
+ */
+ if (list_empty(&dest->address_list))
+ error = -ENETUNREACH;
+
out:
if (error)
sctp_bind_addr_clean(dest);