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2017-06-08decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skbMateusz Jurczyk
Verify that the length of the socket buffer is sufficient to cover the nlmsghdr structure before accessing the nlh->nlmsg_len field for further input sanitization. If the client only supplies 1-3 bytes of data in sk_buff, then nlh->nlmsg_len remains partially uninitialized and contains leftover memory from the corresponding kernel allocation. Operating on such data may result in indeterminate evaluation of the nlmsg_len < sizeof(*nlh) expression. The bug was discovered by a runtime instrumentation designed to detect use of uninitialized memory in the kernel. The patch prevents this and other similar tools (e.g. KMSAN) from flagging this behavior in the future. Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-08Revert "decnet: dn_rtmsg: Improve input length sanitization in ↵David S. Miller
dnrmg_receive_user_skb" This reverts commit 85eac2ba35a2dbfbdd5767c7447a4af07444a5b4. There is an updated version of this fix which we should use instead. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-08decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skbMateusz Jurczyk
Verify that the length of the socket buffer is sufficient to cover the entire nlh->nlmsg_len field before accessing that field for further input sanitization. If the client only supplies 1-3 bytes of data in sk_buff, then nlh->nlmsg_len remains partially uninitialized and contains leftover memory from the corresponding kernel allocation. Operating on such data may result in indeterminate evaluation of the nlmsg_len < sizeof(*nlh) expression. The bug was discovered by a runtime instrumentation designed to detect use of uninitialized memory in the kernel. The patch prevents this and other similar tools (e.g. KMSAN) from flagging this behavior in the future. Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-nextDavid S. Miller
Pablo Neira Ayuso says: ==================== Netfilter/IPVS updates for net-next The following patchset contains Netfilter updates for your net-next tree. A large bunch of code cleanups, simplify the conntrack extension codebase, get rid of the fake conntrack object, speed up netns by selective synchronize_net() calls. More specifically, they are: 1) Check for ct->status bit instead of using nfct_nat() from IPVS and Netfilter codebase, patch from Florian Westphal. 2) Use kcalloc() wherever possible in the IPVS code, from Varsha Rao. 3) Simplify FTP IPVS helper module registration path, from Arushi Singhal. 4) Introduce nft_is_base_chain() helper function. 5) Enforce expectation limit from userspace conntrack helper, from Gao Feng. 6) Add nf_ct_remove_expect() helper function, from Gao Feng. 7) NAT mangle helper function return boolean, from Gao Feng. 8) ctnetlink_alloc_expect() should only work for conntrack with helpers, from Gao Feng. 9) Add nfnl_msg_type() helper function to nfnetlink to build the netlink message type. 10) Get rid of unnecessary cast on void, from simran singhal. 11) Use seq_puts()/seq_putc() instead of seq_printf() where possible, also from simran singhal. 12) Use list_prev_entry() from nf_tables, from simran signhal. 13) Remove unnecessary & on pointer function in the Netfilter and IPVS code. 14) Remove obsolete comment on set of rules per CPU in ip6_tables, no longer true. From Arushi Singhal. 15) Remove duplicated nf_conntrack_l4proto_udplite4, from Gao Feng. 16) Remove unnecessary nested rcu_read_lock() in __nf_nat_decode_session(). Code running from hooks are already guaranteed to run under RCU read side. 17) Remove deadcode in nf_tables_getobj(), from Aaron Conole. 18) Remove double assignment in nf_ct_l4proto_pernet_unregister_one(), also from Aaron. 19) Get rid of unsed __ip_set_get_netlink(), from Aaron Conole. 20) Don't propagate NF_DROP error to userspace via ctnetlink in __nf_nat_alloc_null_binding() function, from Gao Feng. 21) Revisit nf_ct_deliver_cached_events() to remove unnecessary checks, from Gao Feng. 22) Kill the fake untracked conntrack objects, use ctinfo instead to annotate a conntrack object is untracked, from Florian Westphal. 23) Remove nf_ct_is_untracked(), now obsolete since we have no conntrack template anymore, from Florian. 24) Add event mask support to nft_ct, also from Florian. 25) Move nf_conn_help structure to include/net/netfilter/nf_conntrack_helper.h. 26) Add a fixed 32 bytes scratchpad area for conntrack helpers. Thus, we don't deal with variable conntrack extensions anymore. Make sure userspace conntrack helper doesn't go over that size. Remove variable size ct extension infrastructure now this code got no more clients. From Florian Westphal. 27) Restore offset and length of nf_ct_ext structure to 8 bytes now that wraparound is not possible any longer, also from Florian. 28) Allow to get rid of unassured flows under stress in conntrack, this applies to DCCP, SCTP and TCP protocols, from Florian. 29) Shrink size of nf_conntrack_ecache structure, from Florian. 30) Use TCP_MAX_WSCALE instead of hardcoded 14 in TCP tracker, from Gao Feng. 31) Register SYNPROXY hooks on demand, from Florian Westphal. 32) Use pernet hook whenever possible, instead of global hook registration, from Florian Westphal. 33) Pass hook structure to ebt_register_table() to consolidate some infrastructure code, from Florian Westphal. 34) Use consume_skb() and return NF_STOLEN, instead of NF_DROP in the SYNPROXY code, to make sure device stats are not fooled, patch from Gao Feng. 35) Remove NF_CT_EXT_F_PREALLOC this kills quite some code that we don't need anymore if we just select a fixed size instead of expensive runtime time calculation of this. From Florian. 36) Constify nf_ct_extend_register() and nf_ct_extend_unregister(), from Florian. 37) Simplify nf_ct_ext_add(), this kills nf_ct_ext_create(), from Florian. 38) Attach NAT extension on-demand from masquerade and pptp helper path, from Florian. 39) Get rid of useless ip_vs_set_state_timeout(), from Aaron Conole. 40) Speed up netns by selective calls of synchronize_net(), from Florian Westphal. 41) Silence stack size warning gcc in 32-bit arch in snmp helper, from Florian. 42) Inconditionally call nf_ct_ext_destroy(), even if we have no extensions, to deal with the NF_NAT_MANIP_SRC case. Patch from Liping Zhang. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-26netfilter: decnet: only register hooks in init namespaceFlorian Westphal
looks like decnet isn't namespacified in first place, so restrict hook registration to the initial namespace. Prepares for eventual removal of legacy nf_register_hook() api. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2017-04-13netlink: extended ACK reportingJohannes Berg
Add the base infrastructure and UAPI for netlink extended ACK reporting. All "manual" calls to netlink_ack() pass NULL for now and thus don't get extended ACK reporting. Big thanks goes to Pablo Neira Ayuso for not only bringing up the whole topic at netconf (again) but also coming up with the nlattr passing trick and various other ideas. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Reviewed-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-09-18netfilter: Pass priv instead of nf_hook_ops to netfilter hooksEric W. Biederman
Only pass the void *priv parameter out of the nf_hook_ops. That is all any of the functions are interested now, and by limiting what is passed it becomes simpler to change implementation details. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-04-04netfilter: Make nf_hookfn use nf_hook_state.David S. Miller
Pass the nf_hook_state all the way down into the hook functions themselves. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-24net: Use netlink_ns_capable to verify the permisions of netlink messagesEric W. Biederman
It is possible by passing a netlink socket to a more privileged executable and then to fool that executable into writing to the socket data that happens to be valid netlink message to do something that privileged executable did not intend to do. To keep this from happening replace bare capable and ns_capable calls with netlink_capable, netlink_net_calls and netlink_ns_capable calls. Which act the same as the previous calls except they verify that the opener of the socket had the desired permissions as well. Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-14netfilter: pass hook ops to hookfnPatrick McHardy
Pass the hook ops to the hookfn to allow for generic hook functions. This change is required by nf_tables. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2013-03-28net-next: replace obsolete NLMSG_* with type safe nlmsg_*Hong zhi guo
Signed-off-by: Hong Zhiguo <honkiko@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-11net/decnet/netfilter: remove depends on CONFIG_EXPERIMENTALKees Cook
The CONFIG_EXPERIMENTAL config item has not carried much meaning for a while now and is almost always enabled by default. As agreed during the Linux kernel summit, remove it from any "depends on" lines in Kconfigs. CC: Pablo Neira Ayuso <pablo@netfilter.org> CC: Patrick McHardy <kaber@trash.net> CC: "David S. Miller" <davem@davemloft.net> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: David S. Miller <davem@davemloft.net>
2012-09-08netlink: hide struct module parameter in netlink_kernel_createPablo Neira Ayuso
This patch defines netlink_kernel_create as a wrapper function of __netlink_kernel_create to hide the struct module *me parameter (which seems to be THIS_MODULE in all existing netlink subsystems). Suggested by David S. Miller. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-29netlink: add netlink_kernel_cfg parameter to netlink_kernel_createPablo Neira Ayuso
This patch adds the following structure: struct netlink_kernel_cfg { unsigned int groups; void (*input)(struct sk_buff *skb); struct mutex *cb_mutex; }; That can be passed to netlink_kernel_create to set optional configurations for netlink kernel sockets. I've populated this structure by looking for NULL and zero parameters at the existing code. The remaining parameters that always need to be set are still left in the original interface. That includes optional parameters for the netlink socket creation. This allows easy extensibility of this interface in the future. This patch also adapts all callers to use this new interface. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-26decnet: dn_rtmsg: Move away from NLMSG_PUT().David S. Miller
And use nlmsg_data() while we're here too. Also, remove pointless kernel log message. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-07netfilter: decnet: switch hook PFs to nfprotoAlban Crequy
This patch is a cleanup. Use NFPROTO_* for consistency with other netfilter code. Signed-off-by: Alban Crequy <alban.crequy@collabora.co.uk> Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Reviewed-by: Vincent Sanders <vincent.sanders@collabora.co.uk> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2012-05-15net: Convert net_ratelimit uses to net_<level>_ratelimitedJoe Perches
Standardize the net core ratelimited logging functions. Coalesce formats, align arguments. Change a printk then vprintk sequence to use printf extension %pV. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-05security: remove the security_netlink_recv hook as it is equivalent to capable()Eric Paris
Once upon a time netlink was not sync and we had to get the effective capabilities from the skb that was being received. Today we instead get the capabilities from the current task. This has rendered the entire purpose of the hook moot as it is now functionally equivalent to the capable() call. Signed-off-by: Eric Paris <eparis@redhat.com>
2011-07-01decnet: Reduce switch/case indentJoe Perches
Make the case labels the same indent as the switch. git diff -w shows differences for line wrapping. (fit multiple lines to 80 columns, join where possible) Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2008-01-28[NETNS]: Consolidate kernel netlink socket destruction.Denis V. Lunev
Create a specific helper for netlink kernel socket disposal. This just let the code look better and provides a ground for proper disposal inside a namespace. Signed-off-by: Denis V. Lunev <den@openvz.org> Tested-by: Alexey Dobriyan <adobriyan@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETFILTER]: Add CONFIG_NETFILTER_ADVANCED optionPatrick McHardy
The NETFILTER_ADVANCED option hides lots of the rather obscure netfilter options when disabled and provides defaults (M) that should allow to run a distribution firewall without further thinking. Defaults to 'y' to avoid breaking current configurations. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETFILTER]: Mark hooks __read_mostlyPatrick McHardy
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[NETFILTER]: Replace sk_buff ** with sk_buff *Herbert Xu
With all the users of the double pointers removed, this patch mops up by finally replacing all occurances of sk_buff ** in the netfilter API by sk_buff *. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET]: make netlink user -> kernel interface synchroniousDenis V. Lunev
This patch make processing netlink user -> kernel messages synchronious. This change was inspired by the talk with Alexey Kuznetsov about current netlink messages processing. He says that he was badly wrong when introduced asynchronious user -> kernel communication. The call netlink_unicast is the only path to send message to the kernel netlink socket. But, unfortunately, it is also used to send data to the user. Before this change the user message has been attached to the socket queue and sk->sk_data_ready was called. The process has been blocked until all pending messages were processed. The bad thing is that this processing may occur in the arbitrary process context. This patch changes nlk->data_ready callback to get 1 skb and force packet processing right in the netlink_unicast. Kernel -> user path in netlink_unicast remains untouched. EINTR processing for in netlink_run_queue was changed. It forces rtnl_lock drop, but the process remains in the cycle until the message will be fully processed. So, there is no need to use this kludges now. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET]: Support multiple network namespaces with netlinkEric W. Biederman
Each netlink socket will live in exactly one network namespace, this includes the controlling kernel sockets. This patch updates all of the existing netlink protocols to only support the initial network namespace. Request by clients in other namespaces will get -ECONREFUSED. As they would if the kernel did not have the support for that netlink protocol compiled in. As each netlink protocol is updated to be multiple network namespace safe it can register multiple kernel sockets to acquire a presence in the rest of the network namespaces. The implementation in af_netlink is a simple filter implementation at hash table insertion and hash table look up time. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NETLINK]: Switch cb_lock spinlock to mutex and allow to override itPatrick McHardy
Switch cb_lock to mutex and allow netlink kernel users to override it with a subsystem specific mutex for consistent locking in dump callbacks. All netlink_dump_start users have been audited not to rely on any side-effects of the previously used spinlock. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Some more conversions to skb_copy_from_linear_dataArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
2007-04-25[NETLINK]: Introduce nlmsg_hdr() helperArnaldo Carvalho de Melo
For the common "(struct nlmsghdr *)skb->data" sequence, so that we reduce the number of direct accesses to skb->data and for consistency with all the other cast skb member helpers. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Convert skb->tail to sk_buff_data_tArnaldo Carvalho de Melo
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes on 64bit architectures, allowing us to combine the 4 bytes hole left by the layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4 64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN... :-) Many calculations that previously required that skb->{transport,network, mac}_header be first converted to a pointer now can be done directly, being meaningful as offsets or pointers. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-10[NET] DECNET: Fix whitespace errors.YOSHIFUJI Hideaki
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-29[NETLINK]: Encapsulate eff_cap usage within security framework.Darrel Goeddel
This patch encapsulates the usage of eff_cap (in netlink_skb_params) within the security framework by extending security_netlink_recv to include a required capability parameter and converting all direct usage of eff_caps outside of the lsm modules to use the interface. It also updates the SELinux implementation of the security_netlink_send and security_netlink_recv hooks to take advantage of the sid in the netlink_skb_params struct. This also enables SELinux to perform auditing of netlink capability checks. Please apply, for 2.6.18 if possible. Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-28[NETFILTER]: Rename init functions.Andrew Morton
Every netfilter module uses `init' for its module_init() function and `fini' or `cleanup' for its module_exit() function. Problem is, this creates uninformative initcall_debug output and makes ctags rather useless. So go through and rename them all to $(filename)_init and $(filename)_fini. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-11netfilter: headers included twiceNicolas Kaiser
Headers included twice. Signed-off-by: Nicolas Kaiser <nikai@nikai.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2005-08-29[DECNET]: Fix build after netlink changes.Andrew Morton
Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Add "groups" argument to netlink_kernel_createPatrick McHardy
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Convert netlink users to use group numbers instead of bitmasksPatrick McHardy
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Add properly module refcounting for kernel netlink sockets.Harald Welte
- Remove bogus code for compiling netlink as module - Add module refcounting support for modules implementing a netlink protocol - Add support for autoloading modules that implement a netlink protocol as soon as someone opens a socket for that protocol Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-05-03[NETLINK]: Fix infinite loops in synchronous netlink changes.David S. Miller
The qlen should continue to decrement, even if we pop partially processed SKBs back onto the receive queue. Signed-off-by: David S. Miller <davem@davemloft.net>
2005-05-03[NETLINK]: Synchronous message processing.Herbert Xu
Let's recap the problem. The current asynchronous netlink kernel message processing is vulnerable to these attacks: 1) Hit and run: Attacker sends one or more messages and then exits before they're processed. This may confuse/disable the next netlink user that gets the netlink address of the attacker since it may receive the responses to the attacker's messages. Proposed solutions: a) Synchronous processing. b) Stream mode socket. c) Restrict/prohibit binding. 2) Starvation: Because various netlink rcv functions were written to not return until all messages have been processed on a socket, it is possible for these functions to execute for an arbitrarily long period of time. If this is successfully exploited it could also be used to hold rtnl forever. Proposed solutions: a) Synchronous processing. b) Stream mode socket. Firstly let's cross off solution c). It only solves the first problem and it has user-visible impacts. In particular, it'll break user space applications that expect to bind or communicate with specific netlink addresses (pid's). So we're left with a choice of synchronous processing versus SOCK_STREAM for netlink. For the moment I'm sticking with the synchronous approach as suggested by Alexey since it's simpler and I'd rather spend my time working on other things. However, it does have a number of deficiencies compared to the stream mode solution: 1) User-space to user-space netlink communication is still vulnerable. 2) Inefficient use of resources. This is especially true for rtnetlink since the lock is shared with other users such as networking drivers. The latter could hold the rtnl while communicating with hardware which causes the rtnetlink user to wait when it could be doing other things. 3) It is still possible to DoS all netlink users by flooding the kernel netlink receive queue. The attacker simply fills the receive socket with a single netlink message that fills up the entire queue. The attacker then continues to call sendmsg with the same message in a loop. Point 3) can be countered by retransmissions in user-space code, however it is pretty messy. In light of these problems (in particular, point 3), we should implement stream mode netlink at some point. In the mean time, here is a patch that implements synchronous processing. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!