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Tung Nguyen ceb1eb2fb6 tipc: fix memory leak caused by tipc_buf_append()
Commit ed42989eab ("tipc: fix the skb_unshare() in tipc_buf_append()")
replaced skb_unshare() with skb_copy() to not reduce the data reference
counter of the original skb intentionally. This is not the correct
way to handle the cloned skb because it causes memory leak in 2
following cases:
 1/ Sending multicast messages via broadcast link
  The original skb list is cloned to the local skb list for local
  destination. After that, the data reference counter of each skb
  in the original list has the value of 2. This causes each skb not
  to be freed after receiving ACK:
  tipc_link_advance_transmq()
  {
   ...
   /* release skb */
   __skb_unlink(skb, &l->transmq);
   kfree_skb(skb); <-- memory exists after being freed
  }

 2/ Sending multicast messages via replicast link
  Similar to the above case, each skb cannot be freed after purging
  the skb list:
  tipc_mcast_xmit()
  {
   ...
   __skb_queue_purge(pkts); <-- memory exists after being freed
  }

This commit fixes this issue by using skb_unshare() instead. Besides,
to avoid use-after-free error reported by KASAN, the pointer to the
fragment is set to NULL before calling skb_unshare() to make sure that
the original skb is not freed after freeing the fragment 2 times in
case skb_unshare() returns NULL.

Fixes: ed42989eab ("tipc: fix the skb_unshare() in tipc_buf_append()")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Reported-by: Thang Hoang Ngo <thang.h.ngo@dektech.com.au>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://lore.kernel.org/r/20201027032403.1823-1-tung.q.nguyen@dektech.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-29 09:51:52 -07:00
arch ARM: 2020-10-23 11:17:56 -07:00
block docs: bio: fix a kerneldoc markup 2020-10-15 07:49:48 +02:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
Documentation Fixes for 5.10-rc1 from the networking tree: 2020-10-23 12:05:49 -07:00
drivers gtp: fix an use-before-init in gtp_newlink() 2020-10-29 09:43:21 -07:00
fs Changes in gfs2: 2020-10-23 11:47:42 -07:00
include Fixes for 5.10-rc1 from the networking tree: 2020-10-23 12:05:49 -07:00
init linux-kselftest-kunit-5.10-rc1 2020-10-18 14:45:59 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Fixes for 5.10-rc1 from the networking tree: 2020-10-23 12:05:49 -07:00
lib Kbuild updates for v5.10 2020-10-22 13:13:57 -07:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm Refactored code for 5.10: 2020-10-23 11:33:41 -07:00
net tipc: fix memory leak caused by tipc_buf_append() 2020-10-29 09:51:52 -07:00
samples bpf, libbpf: Guard bpf inline asm from bpf_tail_call_static 2020-10-22 01:46:52 +02:00
scripts Fixes for 5.10-rc1 from the networking tree: 2020-10-23 12:05:49 -07:00
security task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
sound dma-mapping updates for 5.10 2020-10-15 14:43:29 -07:00
tools Fixes for 5.10-rc1 from the networking tree: 2020-10-23 12:05:49 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap MAINTAINERS: jarkko.sakkinen@linux.intel.com -> jarkko@kernel.org 2020-10-16 11:11:19 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS networking changes for the 5.10 merge window 2020-10-15 18:42:13 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Fixes for 5.10-rc1 from the networking tree: 2020-10-23 12:05:49 -07:00
Makefile Kbuild updates for v5.10 2020-10-22 13:13:57 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.