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Filename Latest commit message Latest commit date
Dave Wysochanski 0070ed3d9e Fix 16-byte memory leak in gssp_accept_sec_context_upcall
There is a 16-byte memory leak inside sunrpc/auth_gss on an nfs server when
a client mounts with 'sec=krb5' in a simple mount / umount loop.  The leak
is seen by either monitoring the kmalloc-16 slab or with kmemleak enabled

unreferenced object 0xffff92e6a045f030 (size 16):
  comm "nfsd", pid 1096, jiffies 4294936658 (age 761.110s)
  hex dump (first 16 bytes):
    2a 86 48 86 f7 12 01 02 02 00 00 00 00 00 00 00  *.H.............
  backtrace:
    [<000000004b2b79a7>] gssx_dec_buffer+0x79/0x90 [auth_rpcgss]
    [<000000002610ac1a>] gssx_dec_accept_sec_context+0x215/0x6dd [auth_rpcgss]
    [<000000004fd0e81d>] rpcauth_unwrap_resp+0xa9/0xe0 [sunrpc]
    [<000000002b099233>] call_decode+0x1e9/0x840 [sunrpc]
    [<00000000954fc846>] __rpc_execute+0x80/0x3f0 [sunrpc]
    [<00000000c83a961c>] rpc_run_task+0x10d/0x150 [sunrpc]
    [<000000002c2cdcd2>] rpc_call_sync+0x4d/0xa0 [sunrpc]
    [<000000000b74eea2>] gssp_accept_sec_context_upcall+0x196/0x470 [auth_rpcgss]
    [<000000003271273f>] svcauth_gss_proxy_init+0x188/0x520 [auth_rpcgss]
    [<000000001cf69f01>] svcauth_gss_accept+0x3a6/0xb50 [auth_rpcgss]

If you map the above to code you'll see the following call chain
  gssx_dec_accept_sec_context
    gssx_dec_ctx  (missing from kmemleak output)
      gssx_dec_buffer(xdr, &ctx->mech)

Inside gssx_dec_buffer there is 'kmemdup' where we allocate memory for
any gssx_buffer (buf) and store into buf->data.  In the above instance,
'buf == &ctx->mech).

Further up in the chain in gssp_accept_sec_context_upcall we see ctx->mech
is part of a stack variable 'struct gssx_ctx rctxh'.  Now later inside
gssp_accept_sec_context_upcall after gssp_call, there is a number of
memcpy and kfree statements, but there is no kfree(rctxh.mech.data)
after the memcpy into data->mech_oid.data.

With this patch applied and the same mount / unmount loop, the kmalloc-16
slab is stable and kmemleak enabled no longer shows the above backtrace.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-06-08 16:28:55 -04:00
arch KVM fixes for v4.17-rc4 2018-05-06 05:46:29 -10:00
block blk-mq: fix sysfs inflight counter 2018-04-26 09:02:01 -06:00
certs
crypto crypto: drbg - set freed buffers to NULL 2018-04-21 00:57:00 +08:00
Documentation media fixes for v4.17-rc4 2018-05-04 05:38:51 -10:00
drivers IOMMU Fixes for Linux v4.17-rc4 2018-05-06 05:42:24 -10:00
firmware
fs nfsd: Do not refuse to serve out of cache 2018-05-11 15:48:57 -04:00
include svcrdma: Remove unused svc_rdma_op_ctxt 2018-05-11 15:48:57 -04:00
init Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-15 16:12:35 -07:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-13 17:10:27 -07:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-06 05:35:23 -10:00
lib swiotlb: fix inversed DMA_ATTR_NO_WARN test 2018-05-02 14:48:55 +02:00
LICENSES
mm for-linus-20180504 2018-05-04 20:41:44 -10:00
net Fix 16-byte memory leak in gssp_accept_sec_context_upcall 2018-06-08 16:28:55 -04:00
samples bpf: sockmap sample use clang flag, -target bpf 2018-04-23 23:42:21 +02:00
scripts Kbuild fixes for v4.17 2018-05-04 21:15:25 -10:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-24 17:58:51 -07:00
sound ALSA: pcm: Check PCM state at xfern compat ioctl 2018-05-02 08:54:54 +02:00
tools ACPI fix for 4.17-rc4 2018-05-04 05:43:33 -10:00
usr
virt KVM/arm fixes for 4.17, take #2 2018-05-05 23:05:31 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Kbuild fixes for v4.17 2018-05-04 21:15:25 -10:00
Makefile Linux 4.17-rc4 2018-05-06 16:57:38 -10:00
README

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.