<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/samples, branch v5.7.7</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>bpf, xdp, samples: Fix null pointer dereference in *_user code</title>
<updated>2020-06-30T19:36:03+00:00</updated>
<author>
<name>Gaurav Singh</name>
<email>gaurav1086@gmail.com</email>
</author>
<published>2020-06-12T18:53:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3c446f13ffd24be09843ae4f2f3757c68b87a32e'/>
<id>3c446f13ffd24be09843ae4f2f3757c68b87a32e</id>
<content type='text'>
[ Upstream commit 6903cdae9f9f08d61e49c16cbef11c293e33a615 ]

Memset on the pointer right after malloc can cause a NULL pointer
deference if it failed to allocate memory. A simple fix is to
replace malloc()/memset() pair with a simple call to calloc().

Fixes: 0fca931a6f21 ("samples/bpf: program demonstrating access to xdp_rxq_info")
Signed-off-by: Gaurav Singh &lt;gaurav1086@gmail.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6903cdae9f9f08d61e49c16cbef11c293e33a615 ]

Memset on the pointer right after malloc can cause a NULL pointer
deference if it failed to allocate memory. A simple fix is to
replace malloc()/memset() pair with a simple call to calloc().

Fixes: 0fca931a6f21 ("samples/bpf: program demonstrating access to xdp_rxq_info")
Signed-off-by: Gaurav Singh &lt;gaurav1086@gmail.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>samples/bpf: xdp_redirect_cpu: Set MAX_CPUS according to NR_CPUS</title>
<updated>2020-06-30T19:36:03+00:00</updated>
<author>
<name>Lorenzo Bianconi</name>
<email>lorenzo@kernel.org</email>
</author>
<published>2020-05-12T16:30:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4af5b6b255b9b887e192a3eaeeb17093d38abc5c'/>
<id>4af5b6b255b9b887e192a3eaeeb17093d38abc5c</id>
<content type='text'>
[ Upstream commit 6a09815428547657f3ffd2f5c31ac2a191e7fdf3 ]

xdp_redirect_cpu is currently failing in bpf_prog_load_xattr()
allocating cpu_map map if CONFIG_NR_CPUS is less than 64 since
cpu_map_alloc() requires max_entries to be less than NR_CPUS.
Set cpu_map max_entries according to NR_CPUS in xdp_redirect_cpu_kern.c
and get currently running cpus in xdp_redirect_cpu_user.c

Signed-off-by: Lorenzo Bianconi &lt;lorenzo@kernel.org&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Yonghong Song &lt;yhs@fb.com&gt;
Link: https://lore.kernel.org/bpf/374472755001c260158c4e4b22f193bdd3c56fb7.1589300442.git.lorenzo@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6a09815428547657f3ffd2f5c31ac2a191e7fdf3 ]

xdp_redirect_cpu is currently failing in bpf_prog_load_xattr()
allocating cpu_map map if CONFIG_NR_CPUS is less than 64 since
cpu_map_alloc() requires max_entries to be less than NR_CPUS.
Set cpu_map max_entries according to NR_CPUS in xdp_redirect_cpu_kern.c
and get currently running cpus in xdp_redirect_cpu_user.c

Signed-off-by: Lorenzo Bianconi &lt;lorenzo@kernel.org&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Yonghong Song &lt;yhs@fb.com&gt;
Link: https://lore.kernel.org/bpf/374472755001c260158c4e4b22f193bdd3c56fb7.1589300442.git.lorenzo@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sample-trace-array: Fix sleeping function called from invalid context</title>
<updated>2020-06-24T15:49:25+00:00</updated>
<author>
<name>Kefeng Wang</name>
<email>wangkefeng.wang@huawei.com</email>
</author>
<published>2020-06-10T01:12:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2ced99422116c6a05372f353734fbd2abf4f67d2'/>
<id>2ced99422116c6a05372f353734fbd2abf4f67d2</id>
<content type='text'>
commit e9b7b1c0c103a623be1a65c39f98719803440871 upstream.

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/5
 1 lock held by swapper/5/0:
  #0: ffff80001002bd90 (samples/ftrace/sample-trace-array.c:38){+.-.}-{0:0}, at: call_timer_fn+0x8/0x3e0
 CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.7.0+ #8
 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
 Call trace:
  dump_backtrace+0x0/0x1a0
  show_stack+0x20/0x30
  dump_stack+0xe4/0x150
  ___might_sleep+0x160/0x200
  __might_sleep+0x58/0x90
  __mutex_lock+0x64/0x948
  mutex_lock_nested+0x3c/0x58
  __ftrace_set_clr_event+0x44/0x88
  trace_array_set_clr_event+0x24/0x38
  mytimer_handler+0x34/0x40 [sample_trace_array]

mutex_lock() will be called in interrupt context, using workqueue to fix it.

Link: https://lkml.kernel.org/r/20200610011244.2209486-1-wangkefeng.wang@huawei.com

Cc: stable@vger.kernel.org
Fixes: 89ed42495ef4 ("tracing: Sample module to demonstrate kernel access to Ftrace instances.")
Reviewed-by: Divya Indi &lt;divya.indi@oracle.com&gt;
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e9b7b1c0c103a623be1a65c39f98719803440871 upstream.

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/5
 1 lock held by swapper/5/0:
  #0: ffff80001002bd90 (samples/ftrace/sample-trace-array.c:38){+.-.}-{0:0}, at: call_timer_fn+0x8/0x3e0
 CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.7.0+ #8
 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
 Call trace:
  dump_backtrace+0x0/0x1a0
  show_stack+0x20/0x30
  dump_stack+0xe4/0x150
  ___might_sleep+0x160/0x200
  __might_sleep+0x58/0x90
  __mutex_lock+0x64/0x948
  mutex_lock_nested+0x3c/0x58
  __ftrace_set_clr_event+0x44/0x88
  trace_array_set_clr_event+0x24/0x38
  mytimer_handler+0x34/0x40 [sample_trace_array]

mutex_lock() will be called in interrupt context, using workqueue to fix it.

Link: https://lkml.kernel.org/r/20200610011244.2209486-1-wangkefeng.wang@huawei.com

Cc: stable@vger.kernel.org
Fixes: 89ed42495ef4 ("tracing: Sample module to demonstrate kernel access to Ftrace instances.")
Reviewed-by: Divya Indi &lt;divya.indi@oracle.com&gt;
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>sample-trace-array: Remove trace_array 'sample-instance'</title>
<updated>2020-06-24T15:49:25+00:00</updated>
<author>
<name>Kefeng Wang</name>
<email>wangkefeng.wang@huawei.com</email>
</author>
<published>2020-06-09T13:52:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=11afc0d281160e981feb0ebd8aaf62464ba2bf64'/>
<id>11afc0d281160e981feb0ebd8aaf62464ba2bf64</id>
<content type='text'>
commit 9fbc01cdba66e988122ccdc6094cfd85d9587769 upstream.

Remove trace_array 'sample-instance' if kthread_run fails
in sample_trace_array_init().

Link: https://lkml.kernel.org/r/20200609135200.2206726-1-wangkefeng.wang@huawei.com

Cc: stable@vger.kernel.org
Fixes: 89ed42495ef4a ("tracing: Sample module to demonstrate kernel access to Ftrace instances.")
Reviewed-by: Divya Indi &lt;divya.indi@oracle.com&gt;
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 9fbc01cdba66e988122ccdc6094cfd85d9587769 upstream.

Remove trace_array 'sample-instance' if kthread_run fails
in sample_trace_array_init().

Link: https://lkml.kernel.org/r/20200609135200.2206726-1-wangkefeng.wang@huawei.com

Cc: stable@vger.kernel.org
Fixes: 89ed42495ef4a ("tracing: Sample module to demonstrate kernel access to Ftrace instances.")
Reviewed-by: Divya Indi &lt;divya.indi@oracle.com&gt;
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2020-05-15T20:10:06+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-05-15T20:10:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f85c1598ddfe83f61d0656bd1d2025fa3b148b99'/>
<id>f85c1598ddfe83f61d0656bd1d2025fa3b148b99</id>
<content type='text'>
Pull networking fixes from David Miller:

 1) Fix sk_psock reference count leak on receive, from Xiyu Yang.

 2) CONFIG_HNS should be invisible, from Geert Uytterhoeven.

 3) Don't allow locking route MTUs in ipv6, RFCs actually forbid this,
    from Maciej Żenczykowski.

 4) ipv4 route redirect backoff wasn't actually enforced, from Paolo
    Abeni.

 5) Fix netprio cgroup v2 leak, from Zefan Li.

 6) Fix infinite loop on rmmod in conntrack, from Florian Westphal.

 7) Fix tcp SO_RCVLOWAT hangs, from Eric Dumazet.

 8) Various bpf probe handling fixes, from Daniel Borkmann.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (68 commits)
  selftests: mptcp: pm: rm the right tmp file
  dpaa2-eth: properly handle buffer size restrictions
  bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus specifier
  bpf: Add bpf_probe_read_{user, kernel}_str() to do_refine_retval_range
  bpf: Restrict bpf_probe_read{, str}() only to archs where they work
  MAINTAINERS: Mark networking drivers as Maintained.
  ipmr: Add lockdep expression to ipmr_for_each_table macro
  ipmr: Fix RCU list debugging warning
  drivers: net: hamradio: Fix suspicious RCU usage warning in bpqether.c
  net: phy: broadcom: fix BCM54XX_SHD_SCR3_TRDDAPD value for BCM54810
  tcp: fix error recovery in tcp_zerocopy_receive()
  MAINTAINERS: Add Jakub to networking drivers.
  MAINTAINERS: another add of Karsten Graul for S390 networking
  drivers: ipa: fix typos for ipa_smp2p structure doc
  pppoe: only process PADT targeted at local interfaces
  selftests/bpf: Enforce returning 0 for fentry/fexit programs
  bpf: Enforce returning 0 for fentry/fexit progs
  net: stmmac: fix num_por initialization
  security: Fix the default value of secid_to_secctx hook
  libbpf: Fix register naming in PT_REGS s390 macros
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from David Miller:

 1) Fix sk_psock reference count leak on receive, from Xiyu Yang.

 2) CONFIG_HNS should be invisible, from Geert Uytterhoeven.

 3) Don't allow locking route MTUs in ipv6, RFCs actually forbid this,
    from Maciej Żenczykowski.

 4) ipv4 route redirect backoff wasn't actually enforced, from Paolo
    Abeni.

 5) Fix netprio cgroup v2 leak, from Zefan Li.

 6) Fix infinite loop on rmmod in conntrack, from Florian Westphal.

 7) Fix tcp SO_RCVLOWAT hangs, from Eric Dumazet.

 8) Various bpf probe handling fixes, from Daniel Borkmann.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (68 commits)
  selftests: mptcp: pm: rm the right tmp file
  dpaa2-eth: properly handle buffer size restrictions
  bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus specifier
  bpf: Add bpf_probe_read_{user, kernel}_str() to do_refine_retval_range
  bpf: Restrict bpf_probe_read{, str}() only to archs where they work
  MAINTAINERS: Mark networking drivers as Maintained.
  ipmr: Add lockdep expression to ipmr_for_each_table macro
  ipmr: Fix RCU list debugging warning
  drivers: net: hamradio: Fix suspicious RCU usage warning in bpqether.c
  net: phy: broadcom: fix BCM54XX_SHD_SCR3_TRDDAPD value for BCM54810
  tcp: fix error recovery in tcp_zerocopy_receive()
  MAINTAINERS: Add Jakub to networking drivers.
  MAINTAINERS: another add of Karsten Graul for S390 networking
  drivers: ipa: fix typos for ipa_smp2p structure doc
  pppoe: only process PADT targeted at local interfaces
  selftests/bpf: Enforce returning 0 for fentry/fexit programs
  bpf: Enforce returning 0 for fentry/fexit progs
  net: stmmac: fix num_por initialization
  security: Fix the default value of secid_to_secctx hook
  libbpf: Fix register naming in PT_REGS s390 macros
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>samples: bpf: Fix build error</title>
<updated>2020-05-14T19:37:39+00:00</updated>
<author>
<name>Matteo Croce</name>
<email>mcroce@redhat.com</email>
</author>
<published>2020-05-11T11:32:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=23ad04669f81f958e9a4121b0266228d2eb3c357'/>
<id>23ad04669f81f958e9a4121b0266228d2eb3c357</id>
<content type='text'>
GCC 10 is very strict about symbol clash, and lwt_len_hist_user contains
a symbol which clashes with libbpf:

/usr/bin/ld: samples/bpf/lwt_len_hist_user.o:(.bss+0x0): multiple definition of `bpf_log_buf'; samples/bpf/bpf_load.o:(.bss+0x8c0): first defined here
collect2: error: ld returned 1 exit status

bpf_log_buf here seems to be a leftover, so removing it.

Signed-off-by: Matteo Croce &lt;mcroce@redhat.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Yonghong Song &lt;yhs@fb.com&gt;
Link: https://lore.kernel.org/bpf/20200511113234.80722-1-mcroce@redhat.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
GCC 10 is very strict about symbol clash, and lwt_len_hist_user contains
a symbol which clashes with libbpf:

/usr/bin/ld: samples/bpf/lwt_len_hist_user.o:(.bss+0x0): multiple definition of `bpf_log_buf'; samples/bpf/bpf_load.o:(.bss+0x8c0): first defined here
collect2: error: ld returned 1 exit status

bpf_log_buf here seems to be a leftover, so removing it.

Signed-off-by: Matteo Croce &lt;mcroce@redhat.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Yonghong Song &lt;yhs@fb.com&gt;
Link: https://lore.kernel.org/bpf/20200511113234.80722-1-mcroce@redhat.com
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Fix doc mistakes in trace sample</title>
<updated>2020-05-07T17:32:57+00:00</updated>
<author>
<name>Wei Yang</name>
<email>richard.weiyang@gmail.com</email>
</author>
<published>2020-04-28T21:49:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f094a233e1d5b1c61cc797d204aa28b611058827'/>
<id>f094a233e1d5b1c61cc797d204aa28b611058827</id>
<content type='text'>
As the example below shows, DECLARE_EVENT_CLASS() is used instead of
DEFINE_EVENT_CLASS().

Link: http://lkml.kernel.org/r/20200428214959.11259-1-richard.weiyang@gmail.com

Signed-off-by: Wei Yang &lt;richard.weiyang@gmail.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As the example below shows, DECLARE_EVENT_CLASS() is used instead of
DEFINE_EVENT_CLASS().

Link: http://lkml.kernel.org/r/20200428214959.11259-1-richard.weiyang@gmail.com

Signed-off-by: Wei Yang &lt;richard.weiyang@gmail.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vmalloc: fix remap_vmalloc_range() bounds checks</title>
<updated>2020-04-21T18:11:56+00:00</updated>
<author>
<name>Jann Horn</name>
<email>jannh@google.com</email>
</author>
<published>2020-04-21T01:14:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bdebd6a2831b6fab69eb85cee74a8ba77f1a1cc2'/>
<id>bdebd6a2831b6fab69eb85cee74a8ba77f1a1cc2</id>
<content type='text'>
remap_vmalloc_range() has had various issues with the bounds checks it
promises to perform ("This function checks that addr is a valid
vmalloc'ed area, and that it is big enough to cover the vma") over time,
e.g.:

 - not detecting pgoff&lt;&lt;PAGE_SHIFT overflow

 - not detecting (pgoff&lt;&lt;PAGE_SHIFT)+usize overflow

 - not checking whether addr and addr+(pgoff&lt;&lt;PAGE_SHIFT) are the same
   vmalloc allocation

 - comparing a potentially wildly out-of-bounds pointer with the end of
   the vmalloc region

In particular, since commit fc9702273e2e ("bpf: Add mmap() support for
BPF_MAP_TYPE_ARRAY"), unprivileged users can cause kernel null pointer
dereferences by calling mmap() on a BPF map with a size that is bigger
than the distance from the start of the BPF map to the end of the
address space.

This could theoretically be used as a kernel ASLR bypass, by using
whether mmap() with a given offset oopses or returns an error code to
perform a binary search over the possible address range.

To allow remap_vmalloc_range_partial() to verify that addr and
addr+(pgoff&lt;&lt;PAGE_SHIFT) are in the same vmalloc region, pass the offset
to remap_vmalloc_range_partial() instead of adding it to the pointer in
remap_vmalloc_range().

In remap_vmalloc_range_partial(), fix the check against
get_vm_area_size() by using size comparisons instead of pointer
comparisons, and add checks for pgoff.

Fixes: 833423143c3a ("[PATCH] mm: introduce remap_vmalloc_range()")
Signed-off-by: Jann Horn &lt;jannh@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: stable@vger.kernel.org
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Martin KaFai Lau &lt;kafai@fb.com&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Yonghong Song &lt;yhs@fb.com&gt;
Cc: Andrii Nakryiko &lt;andriin@fb.com&gt;
Cc: John Fastabend &lt;john.fastabend@gmail.com&gt;
Cc: KP Singh &lt;kpsingh@chromium.org&gt;
Link: http://lkml.kernel.org/r/20200415222312.236431-1-jannh@google.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
remap_vmalloc_range() has had various issues with the bounds checks it
promises to perform ("This function checks that addr is a valid
vmalloc'ed area, and that it is big enough to cover the vma") over time,
e.g.:

 - not detecting pgoff&lt;&lt;PAGE_SHIFT overflow

 - not detecting (pgoff&lt;&lt;PAGE_SHIFT)+usize overflow

 - not checking whether addr and addr+(pgoff&lt;&lt;PAGE_SHIFT) are the same
   vmalloc allocation

 - comparing a potentially wildly out-of-bounds pointer with the end of
   the vmalloc region

In particular, since commit fc9702273e2e ("bpf: Add mmap() support for
BPF_MAP_TYPE_ARRAY"), unprivileged users can cause kernel null pointer
dereferences by calling mmap() on a BPF map with a size that is bigger
than the distance from the start of the BPF map to the end of the
address space.

This could theoretically be used as a kernel ASLR bypass, by using
whether mmap() with a given offset oopses or returns an error code to
perform a binary search over the possible address range.

To allow remap_vmalloc_range_partial() to verify that addr and
addr+(pgoff&lt;&lt;PAGE_SHIFT) are in the same vmalloc region, pass the offset
to remap_vmalloc_range_partial() instead of adding it to the pointer in
remap_vmalloc_range().

In remap_vmalloc_range_partial(), fix the check against
get_vm_area_size() by using size comparisons instead of pointer
comparisons, and add checks for pgoff.

Fixes: 833423143c3a ("[PATCH] mm: introduce remap_vmalloc_range()")
Signed-off-by: Jann Horn &lt;jannh@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: stable@vger.kernel.org
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Martin KaFai Lau &lt;kafai@fb.com&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Yonghong Song &lt;yhs@fb.com&gt;
Cc: Andrii Nakryiko &lt;andriin@fb.com&gt;
Cc: John Fastabend &lt;john.fastabend@gmail.com&gt;
Cc: KP Singh &lt;kpsingh@chromium.org&gt;
Link: http://lkml.kernel.org/r/20200415222312.236431-1-jannh@google.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>samples/hw_breakpoint: drop use of kallsyms_lookup_name()</title>
<updated>2020-04-07T17:43:44+00:00</updated>
<author>
<name>Will Deacon</name>
<email>will@kernel.org</email>
</author>
<published>2020-04-07T03:11:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d8a84d33a4954b85c53faf77be48b5c2b559692e'/>
<id>d8a84d33a4954b85c53faf77be48b5c2b559692e</id>
<content type='text'>
The 'data_breakpoint' test code is the only modular user of
kallsyms_lookup_name(), which was exported as part of fixing the test in
f60d24d2ad04 ("hw-breakpoints: Fix broken hw-breakpoint sample module").

In preparation for un-exporting this symbol, switch the test over to using
__symbol_get(), which can be used to place breakpoints on exported
symbols.

Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Reviewed-by: Quentin Perret &lt;qperret@google.com&gt;
Cc: K.Prasad &lt;prasad@linux.vnet.ibm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Miroslav Benes &lt;mbenes@suse.cz&gt;
Cc: Petr Mladek &lt;pmladek@suse.com&gt;
Cc: Joe Lawrence &lt;joe.lawrence@redhat.com&gt;
Link: http://lkml.kernel.org/r/20200221114404.14641-3-will@kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The 'data_breakpoint' test code is the only modular user of
kallsyms_lookup_name(), which was exported as part of fixing the test in
f60d24d2ad04 ("hw-breakpoints: Fix broken hw-breakpoint sample module").

In preparation for un-exporting this symbol, switch the test over to using
__symbol_get(), which can be used to place breakpoints on exported
symbols.

Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Reviewed-by: Quentin Perret &lt;qperret@google.com&gt;
Cc: K.Prasad &lt;prasad@linux.vnet.ibm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Miroslav Benes &lt;mbenes@suse.cz&gt;
Cc: Petr Mladek &lt;pmladek@suse.com&gt;
Cc: Joe Lawrence &lt;joe.lawrence@redhat.com&gt;
Link: http://lkml.kernel.org/r/20200221114404.14641-3-will@kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>samples/hw_breakpoint: drop HW_BREAKPOINT_R when reporting writes</title>
<updated>2020-04-07T17:43:44+00:00</updated>
<author>
<name>Will Deacon</name>
<email>will@kernel.org</email>
</author>
<published>2020-04-07T03:11:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4800314e19d976d88c87e99bcd37d7635eb57f78'/>
<id>4800314e19d976d88c87e99bcd37d7635eb57f78</id>
<content type='text'>
Patch series "Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol()".

Despite having just a single modular in-tree user that I could spot,
kallsyms_lookup_name() is exported to modules and provides a mechanism
for out-of-tree modules to access and invoke arbitrary, non-exported
kernel symbols when kallsyms is enabled.

This patch series fixes up that one user and unexports the symbol along
with kallsyms_on_each_symbol(), since that could also be abused in a
similar manner.

I would like to avoid out-of-tree modules being easily able to call
functions that are not exported.  kallsyms_lookup_name() makes this
trivial to the point that there is very little incentive to rework these
modules to either use upstream interfaces correctly or propose
functionality which may be otherwise missing upstream.  Both of these
latter solutions would be pre-requisites to upstreaming these modules, and
the current state of things actively discourages that approach.

The background here is that we are aiming for Android devices to be able
to use a generic binary kernel image closely following upstream, with any
vendor extensions coming in as kernel modules.  In this case, we (Google)
end up maintaining the binary module ABI within the scope of a single LTS
kernel.  Monitoring and managing the ABI surface is not feasible if it
effectively includes all data and functions via kallsyms_lookup_name().
Of course, we could just carry this patch in the Android kernel tree, but
we're aiming to carry as little as possible (ideally nothing) and I think
it's a sensible change in its own right.  I'm surprised you object to it,
in all honesty.

Now, you could turn around and say "that's not upstream's problem", but it
still seems highly undesirable to me to have an upstream bypass for
exported symbols that isn't even used by upstream modules.  It's ripe for
abuse and encourages people to work outside of the upstream tree.  The
usual rule is that we don't export symbols without a user in the tree and
that seems especially relevant in this case.

Joe Lawrence said:

: FWIW, kallsyms was historically used by the out-of-tree kpatch support
: module to resolve external symbols as well as call set_memory_r{w,o}()
: API.  All of that support code has been merged upstream, so modern kpatch
: modules* no longer leverage kallsyms by default.
:
: That said, there are still some users who still use the deprecated support
: module with newer kernels, but that is not officially supported by the
: project.

This patch (of 3):

Given the name of a kernel symbol, the 'data_breakpoint' test claims to
"report any write operations on the kernel symbol".  However, it creates
the breakpoint using both HW_BREAKPOINT_W and HW_BREAKPOINT_R, which menas
it also fires for read access.

Drop HW_BREAKPOINT_R from the breakpoint attributes.

Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Reviewed-by: Quentin Perret &lt;qperret@google.com&gt;
Cc: K.Prasad &lt;prasad@linux.vnet.ibm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Miroslav Benes &lt;mbenes@suse.cz&gt;
Cc: Petr Mladek &lt;pmladek@suse.com&gt;
Cc: Joe Lawrence &lt;joe.lawrence@redhat.com&gt;
Link: http://lkml.kernel.org/r/20200221114404.14641-2-will@kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Patch series "Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol()".

Despite having just a single modular in-tree user that I could spot,
kallsyms_lookup_name() is exported to modules and provides a mechanism
for out-of-tree modules to access and invoke arbitrary, non-exported
kernel symbols when kallsyms is enabled.

This patch series fixes up that one user and unexports the symbol along
with kallsyms_on_each_symbol(), since that could also be abused in a
similar manner.

I would like to avoid out-of-tree modules being easily able to call
functions that are not exported.  kallsyms_lookup_name() makes this
trivial to the point that there is very little incentive to rework these
modules to either use upstream interfaces correctly or propose
functionality which may be otherwise missing upstream.  Both of these
latter solutions would be pre-requisites to upstreaming these modules, and
the current state of things actively discourages that approach.

The background here is that we are aiming for Android devices to be able
to use a generic binary kernel image closely following upstream, with any
vendor extensions coming in as kernel modules.  In this case, we (Google)
end up maintaining the binary module ABI within the scope of a single LTS
kernel.  Monitoring and managing the ABI surface is not feasible if it
effectively includes all data and functions via kallsyms_lookup_name().
Of course, we could just carry this patch in the Android kernel tree, but
we're aiming to carry as little as possible (ideally nothing) and I think
it's a sensible change in its own right.  I'm surprised you object to it,
in all honesty.

Now, you could turn around and say "that's not upstream's problem", but it
still seems highly undesirable to me to have an upstream bypass for
exported symbols that isn't even used by upstream modules.  It's ripe for
abuse and encourages people to work outside of the upstream tree.  The
usual rule is that we don't export symbols without a user in the tree and
that seems especially relevant in this case.

Joe Lawrence said:

: FWIW, kallsyms was historically used by the out-of-tree kpatch support
: module to resolve external symbols as well as call set_memory_r{w,o}()
: API.  All of that support code has been merged upstream, so modern kpatch
: modules* no longer leverage kallsyms by default.
:
: That said, there are still some users who still use the deprecated support
: module with newer kernels, but that is not officially supported by the
: project.

This patch (of 3):

Given the name of a kernel symbol, the 'data_breakpoint' test claims to
"report any write operations on the kernel symbol".  However, it creates
the breakpoint using both HW_BREAKPOINT_W and HW_BREAKPOINT_R, which menas
it also fires for read access.

Drop HW_BREAKPOINT_R from the breakpoint attributes.

Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Reviewed-by: Quentin Perret &lt;qperret@google.com&gt;
Cc: K.Prasad &lt;prasad@linux.vnet.ibm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Miroslav Benes &lt;mbenes@suse.cz&gt;
Cc: Petr Mladek &lt;pmladek@suse.com&gt;
Cc: Joe Lawrence &lt;joe.lawrence@redhat.com&gt;
Link: http://lkml.kernel.org/r/20200221114404.14641-2-will@kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
