From e7820e39b7d19b9fe1928fc19de9361b44150ca6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 21 Nov 2014 11:47:16 -0800 Subject: net: Revert "net: avoid one atomic operation in skb_clone()" Not sure what I was thinking, but doing anything after releasing a refcount is suicidal or/and embarrassing. By the time we set skb->fclone to SKB_FCLONE_FREE, another cpu could have released last reference and freed whole skb. We potentially corrupt memory or trap if CONFIG_DEBUG_PAGEALLOC is set. Reported-by: Chris Mason Fixes: ce1a4ea3f1258 ("net: avoid one atomic operation in skb_clone()") Signed-off-by: Eric Dumazet Cc: Sabrina Dubroca Signed-off-by: David S. Miller --- net/core/skbuff.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) (limited to 'net/core') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c16615bfb61e..32e31c299631 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -552,20 +552,13 @@ static void kfree_skbmem(struct sk_buff *skb) case SKB_FCLONE_CLONE: fclones = container_of(skb, struct sk_buff_fclones, skb2); - /* Warning : We must perform the atomic_dec_and_test() before - * setting skb->fclone back to SKB_FCLONE_FREE, otherwise - * skb_clone() could set clone_ref to 2 before our decrement. - * Anyway, if we are going to free the structure, no need to - * rewrite skb->fclone. + /* The clone portion is available for + * fast-cloning again. */ - if (atomic_dec_and_test(&fclones->fclone_ref)) { + skb->fclone = SKB_FCLONE_FREE; + + if (atomic_dec_and_test(&fclones->fclone_ref)) kmem_cache_free(skbuff_fclone_cache, fclones); - } else { - /* The clone portion is available for - * fast-cloning again. - */ - skb->fclone = SKB_FCLONE_FREE; - } break; } } @@ -887,11 +880,7 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) if (skb->fclone == SKB_FCLONE_ORIG && n->fclone == SKB_FCLONE_FREE) { n->fclone = SKB_FCLONE_CLONE; - /* As our fastclone was free, clone_ref must be 1 at this point. - * We could use atomic_inc() here, but it is faster - * to set the final value. - */ - atomic_set(&fclones->fclone_ref, 2); + atomic_inc(&fclones->fclone_ref); } else { if (skb_pfmemalloc(skb)) gfp_mask |= __GFP_MEMALLOC; -- cgit v1.2.3 From 6e8d1c55454574a22b3e8e263b1a12888909b033 Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Wed, 26 Nov 2014 13:42:16 +0100 Subject: bridge: Validate IFLA_BRIDGE_FLAGS attribute length Payload is currently accessed blindly and may exceed valid message boundaries. Fixes: 407af3299 ("bridge: Add netlink interface to configure vlans on bridge ports") Cc: Vlad Yasevich Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- net/core/rtnetlink.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'net/core') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index a6882686ca3a..5a853f8fad6c 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2798,6 +2798,9 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh) if (br_spec) { nla_for_each_nested(attr, br_spec, rem) { if (nla_type(attr) == IFLA_BRIDGE_FLAGS) { + if (nla_len(attr) < sizeof(flags)) + return -EINVAL; + have_flags = true; flags = nla_get_u16(attr); break; @@ -2868,6 +2871,9 @@ static int rtnl_bridge_dellink(struct sk_buff *skb, struct nlmsghdr *nlh) if (br_spec) { nla_for_each_nested(attr, br_spec, rem) { if (nla_type(attr) == IFLA_BRIDGE_FLAGS) { + if (nla_len(attr) < sizeof(flags)) + return -EINVAL; + have_flags = true; flags = nla_get_u16(attr); break; -- cgit v1.2.3 From aa68c20ff32f9a6fb3ca7f93ed9beae01899d00d Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Wed, 26 Nov 2014 13:42:20 +0100 Subject: bridge: Sanitize IFLA_EXT_MASK for AF_BRIDGE:RTM_GETLINK Only search for IFLA_EXT_MASK if the message actually carries a ifinfomsg header and validate minimal length requirements for IFLA_EXT_MASK. Fixes: 6cbdceeb ("bridge: Dump vlan information from a bridge port") Cc: Vlad Yasevich Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- net/core/rtnetlink.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'net/core') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 5a853f8fad6c..b9b7dfaf202b 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2685,13 +2685,20 @@ static int rtnl_bridge_getlink(struct sk_buff *skb, struct netlink_callback *cb) int idx = 0; u32 portid = NETLINK_CB(cb->skb).portid; u32 seq = cb->nlh->nlmsg_seq; - struct nlattr *extfilt; u32 filter_mask = 0; - extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct ifinfomsg), - IFLA_EXT_MASK); - if (extfilt) - filter_mask = nla_get_u32(extfilt); + if (nlmsg_len(cb->nlh) > sizeof(struct ifinfomsg)) { + struct nlattr *extfilt; + + extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct ifinfomsg), + IFLA_EXT_MASK); + if (extfilt) { + if (nla_len(extfilt) < sizeof(filter_mask)) + return -EINVAL; + + filter_mask = nla_get_u32(extfilt); + } + } rcu_read_lock(); for_each_netdev_rcu(net, dev) { -- cgit v1.2.3