<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/firmware/efi, branch linux-5.6.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>efi/efivars: Add missing kobject_put() in sysfs entry creation error path</title>
<updated>2020-06-17T14:41:55+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2020-05-22T16:15:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ace87a941529de7cdf3732b6ada7a2c02d972cf6'/>
<id>ace87a941529de7cdf3732b6ada7a2c02d972cf6</id>
<content type='text'>
commit d8bd8c6e2cfab8b78b537715255be8d7557791c0 upstream.

The documentation provided by kobject_init_and_add() clearly spells out
the need to call kobject_put() on the kobject if an error is returned.
Add this missing call to the error path.

Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: 亿一 &lt;teroincn@gmail.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.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 d8bd8c6e2cfab8b78b537715255be8d7557791c0 upstream.

The documentation provided by kobject_init_and_add() clearly spells out
the need to call kobject_put() on the kobject if an error is returned.
Add this missing call to the error path.

Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: 亿一 &lt;teroincn@gmail.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>efi/earlycon: Fix early printk for wider fonts</title>
<updated>2020-06-07T11:16:45+00:00</updated>
<author>
<name>Dave Young</name>
<email>dyoung@redhat.com</email>
</author>
<published>2020-04-12T02:49:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=98b034fecfc32a2abe27bf1d88ea5b9f4591c64f'/>
<id>98b034fecfc32a2abe27bf1d88ea5b9f4591c64f</id>
<content type='text'>
[ Upstream commit 8f592ada59b321d248391bae175cd78a12972223 ]

When I play with terminus fonts I noticed the efi early printk does
not work because the earlycon code assumes font width is 8.

Here add the code to adapt with larger fonts.  Tested with all kinds
of kernel built-in fonts on my laptop. Also tested with a local draft
patch for 14x28 !bold terminus font.

Signed-off-by: Dave Young &lt;dyoung@redhat.com&gt;
Link: https://lore.kernel.org/r/20200412024927.GA6884@dhcp-128-65.nay.redhat.com
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&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 8f592ada59b321d248391bae175cd78a12972223 ]

When I play with terminus fonts I noticed the efi early printk does
not work because the earlycon code assumes font width is 8.

Here add the code to adapt with larger fonts.  Tested with all kinds
of kernel built-in fonts on my laptop. Also tested with a local draft
patch for 14x28 !bold terminus font.

Signed-off-by: Dave Young &lt;dyoung@redhat.com&gt;
Link: https://lore.kernel.org/r/20200412024927.GA6884@dhcp-128-65.nay.redhat.com
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>efi/libstub: Avoid returning uninitialized data from setup_graphics()</title>
<updated>2020-06-07T11:16:45+00:00</updated>
<author>
<name>Heinrich Schuchardt</name>
<email>xypron.glpk@gmx.de</email>
</author>
<published>2020-04-26T19:49:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b3482a7a86eb9e3ba9a10bac282478e9a04804fa'/>
<id>b3482a7a86eb9e3ba9a10bac282478e9a04804fa</id>
<content type='text'>
[ Upstream commit 081d5150845ba3fa49151a2f55d3cc03b0987509 ]

Currently, setup_graphics() ignores the return value of efi_setup_gop(). As
AllocatePool() does not zero out memory, the screen information table will
contain uninitialized data in this case.

We should free the screen information table if efi_setup_gop() returns an
error code.

Signed-off-by: Heinrich Schuchardt &lt;xypron.glpk@gmx.de&gt;
Link: https://lore.kernel.org/r/20200426194946.112768-1-xypron.glpk@gmx.de
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&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 081d5150845ba3fa49151a2f55d3cc03b0987509 ]

Currently, setup_graphics() ignores the return value of efi_setup_gop(). As
AllocatePool() does not zero out memory, the screen information table will
contain uninitialized data in this case.

We should free the screen information table if efi_setup_gop() returns an
error code.

Signed-off-by: Heinrich Schuchardt &lt;xypron.glpk@gmx.de&gt;
Link: https://lore.kernel.org/r/20200426194946.112768-1-xypron.glpk@gmx.de
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tpm: check event log version before reading final events</title>
<updated>2020-05-27T15:48:28+00:00</updated>
<author>
<name>Loïc Yhuel</name>
<email>loic.yhuel@gmail.com</email>
</author>
<published>2020-05-12T04:01:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=08731bd847fd661818836fdc5dfb838d620ff499'/>
<id>08731bd847fd661818836fdc5dfb838d620ff499</id>
<content type='text'>
commit b4f1874c62168159fdb419ced4afc77c1b51c475 upstream.

This fixes the boot issues since 5.3 on several Dell models when the TPM
is enabled. Depending on the exact grub binary, booting the kernel would
freeze early, or just report an error parsing the final events log.

We get an event log in the SHA-1 format, which doesn't have a
tcg_efi_specid_event_head in the first event, and there is a final events
table which doesn't match the crypto agile format.
__calc_tpm2_event_size reads bad "count" and "efispecid-&gt;num_algs", and
either fails, or loops long enough for the machine to be appear frozen.

So we now only parse the final events table, which is per the spec always
supposed to be in the crypto agile format, when we got a event log in this
format.

Fixes: c46f3405692de ("tpm: Reserve the TPM final events table")
Fixes: 166a2809d65b2 ("tpm: Don't duplicate events from the final event log in the TCG2 log")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1779611
Signed-off-by: Loïc Yhuel &lt;loic.yhuel@gmail.com&gt;
Link: https://lore.kernel.org/r/20200512040113.277768-1-loic.yhuel@gmail.com
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Reviewed-by: Jerry Snitselaar &lt;jsnitsel@redhat.com&gt;
Reviewed-by: Matthew Garrett &lt;mjg59@google.com&gt;
[ardb: warn when final events table is missing or in the wrong format]
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.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 b4f1874c62168159fdb419ced4afc77c1b51c475 upstream.

This fixes the boot issues since 5.3 on several Dell models when the TPM
is enabled. Depending on the exact grub binary, booting the kernel would
freeze early, or just report an error parsing the final events log.

We get an event log in the SHA-1 format, which doesn't have a
tcg_efi_specid_event_head in the first event, and there is a final events
table which doesn't match the crypto agile format.
__calc_tpm2_event_size reads bad "count" and "efispecid-&gt;num_algs", and
either fails, or loops long enough for the machine to be appear frozen.

So we now only parse the final events table, which is per the spec always
supposed to be in the crypto agile format, when we got a event log in this
format.

Fixes: c46f3405692de ("tpm: Reserve the TPM final events table")
Fixes: 166a2809d65b2 ("tpm: Don't duplicate events from the final event log in the TCG2 log")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1779611
Signed-off-by: Loïc Yhuel &lt;loic.yhuel@gmail.com&gt;
Link: https://lore.kernel.org/r/20200512040113.277768-1-loic.yhuel@gmail.com
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Reviewed-by: Jerry Snitselaar &lt;jsnitsel@redhat.com&gt;
Reviewed-by: Matthew Garrett &lt;mjg59@google.com&gt;
[ardb: warn when final events table is missing or in the wrong format]
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>gcc-10: mark more functions __init to avoid section mismatch warnings</title>
<updated>2020-05-20T06:22:24+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-05-10T00:50:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b08afbbd30d45dcf46125368deb7bd514090efd6'/>
<id>b08afbbd30d45dcf46125368deb7bd514090efd6</id>
<content type='text'>
commit e99332e7b4cda6e60f5b5916cf9943a79dbef902 upstream.

It seems that for whatever reason, gcc-10 ends up not inlining a couple
of functions that used to be inlined before.  Even if they only have one
single callsite - it looks like gcc may have decided that the code was
unlikely, and not worth inlining.

The code generation difference is harmless, but caused a few new section
mismatch errors, since the (now no longer inlined) function wasn't in
the __init section, but called other init functions:

   Section mismatch in reference from the function kexec_free_initrd() to the function .init.text:free_initrd_mem()
   Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memremap()
   Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memunmap()

So add the appropriate __init annotation to make modpost not complain.
In both cases there were trivially just a single callsite from another
__init function.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.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 e99332e7b4cda6e60f5b5916cf9943a79dbef902 upstream.

It seems that for whatever reason, gcc-10 ends up not inlining a couple
of functions that used to be inlined before.  Even if they only have one
single callsite - it looks like gcc may have decided that the code was
unlikely, and not worth inlining.

The code generation difference is harmless, but caused a few new section
mismatch errors, since the (now no longer inlined) function wasn't in
the __init section, but called other init functions:

   Section mismatch in reference from the function kexec_free_initrd() to the function .init.text:free_initrd_mem()
   Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memremap()
   Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memunmap()

So add the appropriate __init annotation to make modpost not complain.
In both cases there were trivially just a single callsite from another
__init function.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>efi/x86: Ignore the memory attributes table on i386</title>
<updated>2020-04-17T14:13:21+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2020-03-08T08:08:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4eff1e8913867cd4d5f34357d97697d6db4a6f8a'/>
<id>4eff1e8913867cd4d5f34357d97697d6db4a6f8a</id>
<content type='text'>
[ Upstream commit dd09fad9d2caad2325a39b766ce9e79cfc690184 ]

Commit:

  3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE initialization common across all architectures")

moved the call to efi_memattr_init() from ARM specific to the generic
EFI init code, in order to be able to apply the restricted permissions
described in that table on x86 as well.

We never enabled this feature fully on i386, and so mapping and
reserving this table is pointless. However, due to the early call to
memblock_reserve(), the memory bookkeeping gets confused to the point
where it produces the splat below when we try to map the memory later
on:

  ------------[ cut here ]------------
  ioremap on RAM at 0x3f251000 - 0x3fa1afff
  WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:166 __ioremap_caller ...
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.20.0 #48
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
  EIP: __ioremap_caller.constprop.0+0x249/0x260
  Code: 90 0f b7 05 4e 38 40 de 09 45 e0 e9 09 ff ff ff 90 8d 45 ec c6 05 ...
  EAX: 00000029 EBX: 00000000 ECX: de59c228 EDX: 00000001
  ESI: 3f250fff EDI: 00000000 EBP: de3edf20 ESP: de3edee0
  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00200296
  CR0: 80050033 CR2: ffd17000 CR3: 1e58c000 CR4: 00040690
  Call Trace:
   ioremap_cache+0xd/0x10
   ? old_map_region+0x72/0x9d
   old_map_region+0x72/0x9d
   efi_map_region+0x8/0xa
   efi_enter_virtual_mode+0x260/0x43b
   start_kernel+0x329/0x3aa
   i386_start_kernel+0xa7/0xab
   startup_32_smp+0x164/0x168
  ---[ end trace e15ccf6b9f356833 ]---

Let's work around this by disregarding the memory attributes table
altogether on i386, which does not result in a loss of functionality
or protection, given that we never consumed the contents.

Fixes: 3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE ... ")
Tested-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Link: https://lore.kernel.org/r/20200304165917.5893-1-ardb@kernel.org
Link: https://lore.kernel.org/r/20200308080859.21568-21-ardb@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 dd09fad9d2caad2325a39b766ce9e79cfc690184 ]

Commit:

  3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE initialization common across all architectures")

moved the call to efi_memattr_init() from ARM specific to the generic
EFI init code, in order to be able to apply the restricted permissions
described in that table on x86 as well.

We never enabled this feature fully on i386, and so mapping and
reserving this table is pointless. However, due to the early call to
memblock_reserve(), the memory bookkeeping gets confused to the point
where it produces the splat below when we try to map the memory later
on:

  ------------[ cut here ]------------
  ioremap on RAM at 0x3f251000 - 0x3fa1afff
  WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:166 __ioremap_caller ...
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.20.0 #48
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
  EIP: __ioremap_caller.constprop.0+0x249/0x260
  Code: 90 0f b7 05 4e 38 40 de 09 45 e0 e9 09 ff ff ff 90 8d 45 ec c6 05 ...
  EAX: 00000029 EBX: 00000000 ECX: de59c228 EDX: 00000001
  ESI: 3f250fff EDI: 00000000 EBP: de3edf20 ESP: de3edee0
  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00200296
  CR0: 80050033 CR2: ffd17000 CR3: 1e58c000 CR4: 00040690
  Call Trace:
   ioremap_cache+0xd/0x10
   ? old_map_region+0x72/0x9d
   old_map_region+0x72/0x9d
   efi_map_region+0x8/0xa
   efi_enter_virtual_mode+0x260/0x43b
   start_kernel+0x329/0x3aa
   i386_start_kernel+0xa7/0xab
   startup_32_smp+0x164/0x168
  ---[ end trace e15ccf6b9f356833 ]---

Let's work around this by disregarding the memory attributes table
altogether on i386, which does not result in a loss of functionality
or protection, given that we never consumed the contents.

Fixes: 3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE ... ")
Tested-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Link: https://lore.kernel.org/r/20200304165917.5893-1-ardb@kernel.org
Link: https://lore.kernel.org/r/20200308080859.21568-21-ardb@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>efi: Add a sanity check to efivar_store_raw()</title>
<updated>2020-03-08T08:56:48+00:00</updated>
<author>
<name>Vladis Dronov</name>
<email>vdronov@redhat.com</email>
</author>
<published>2020-03-08T08:08:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d6c066fda90d578aacdf19771a027ed484a79825'/>
<id>d6c066fda90d578aacdf19771a027ed484a79825</id>
<content type='text'>
Add a sanity check to efivar_store_raw() the same way
efivar_{attr,size,data}_read() and efivar_show_raw() have it.

Signed-off-by: Vladis Dronov &lt;vdronov@redhat.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200305084041.24053-3-vdronov@redhat.com
Link: https://lore.kernel.org/r/20200308080859.21568-25-ardb@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a sanity check to efivar_store_raw() the same way
efivar_{attr,size,data}_read() and efivar_show_raw() have it.

Signed-off-by: Vladis Dronov &lt;vdronov@redhat.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200305084041.24053-3-vdronov@redhat.com
Link: https://lore.kernel.org/r/20200308080859.21568-25-ardb@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>efi: Fix a race and a buffer overflow while reading efivars via sysfs</title>
<updated>2020-03-08T08:56:34+00:00</updated>
<author>
<name>Vladis Dronov</name>
<email>vdronov@redhat.com</email>
</author>
<published>2020-03-08T08:08:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=286d3250c9d6437340203fb64938bea344729a0e'/>
<id>286d3250c9d6437340203fb64938bea344729a0e</id>
<content type='text'>
There is a race and a buffer overflow corrupting a kernel memory while
reading an EFI variable with a size more than 1024 bytes via the older
sysfs method. This happens because accessing struct efi_variable in
efivar_{attr,size,data}_read() and friends is not protected from
a concurrent access leading to a kernel memory corruption and, at best,
to a crash. The race scenario is the following:

CPU0:                                CPU1:
efivar_attr_read()
  var-&gt;DataSize = 1024;
  efivar_entry_get(... &amp;var-&gt;DataSize)
    down_interruptible(&amp;efivars_lock)
                                     efivar_attr_read() // same EFI var
                                       var-&gt;DataSize = 1024;
                                       efivar_entry_get(... &amp;var-&gt;DataSize)
                                         down_interruptible(&amp;efivars_lock)
    virt_efi_get_variable()
    // returns EFI_BUFFER_TOO_SMALL but
    // var-&gt;DataSize is set to a real
    // var size more than 1024 bytes
    up(&amp;efivars_lock)
                                         virt_efi_get_variable()
                                         // called with var-&gt;DataSize set
                                         // to a real var size, returns
                                         // successfully and overwrites
                                         // a 1024-bytes kernel buffer
                                         up(&amp;efivars_lock)

This can be reproduced by concurrent reading of an EFI variable which size
is more than 1024 bytes:

  ts# for cpu in $(seq 0 $(nproc --ignore=1)); do ( taskset -c $cpu \
  cat /sys/firmware/efi/vars/KEKDefault*/size &amp; ) ; done

Fix this by using a local variable for a var's data buffer size so it
does not get overwritten.

Fixes: e14ab23dde12b80d ("efivars: efivar_entry API")
Reported-by: Bob Sanders &lt;bob.sanders@hpe.com&gt; and the LTP testsuite
Signed-off-by: Vladis Dronov &lt;vdronov@redhat.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200305084041.24053-2-vdronov@redhat.com
Link: https://lore.kernel.org/r/20200308080859.21568-24-ardb@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is a race and a buffer overflow corrupting a kernel memory while
reading an EFI variable with a size more than 1024 bytes via the older
sysfs method. This happens because accessing struct efi_variable in
efivar_{attr,size,data}_read() and friends is not protected from
a concurrent access leading to a kernel memory corruption and, at best,
to a crash. The race scenario is the following:

CPU0:                                CPU1:
efivar_attr_read()
  var-&gt;DataSize = 1024;
  efivar_entry_get(... &amp;var-&gt;DataSize)
    down_interruptible(&amp;efivars_lock)
                                     efivar_attr_read() // same EFI var
                                       var-&gt;DataSize = 1024;
                                       efivar_entry_get(... &amp;var-&gt;DataSize)
                                         down_interruptible(&amp;efivars_lock)
    virt_efi_get_variable()
    // returns EFI_BUFFER_TOO_SMALL but
    // var-&gt;DataSize is set to a real
    // var size more than 1024 bytes
    up(&amp;efivars_lock)
                                         virt_efi_get_variable()
                                         // called with var-&gt;DataSize set
                                         // to a real var size, returns
                                         // successfully and overwrites
                                         // a 1024-bytes kernel buffer
                                         up(&amp;efivars_lock)

This can be reproduced by concurrent reading of an EFI variable which size
is more than 1024 bytes:

  ts# for cpu in $(seq 0 $(nproc --ignore=1)); do ( taskset -c $cpu \
  cat /sys/firmware/efi/vars/KEKDefault*/size &amp; ) ; done

Fix this by using a local variable for a var's data buffer size so it
does not get overwritten.

Fixes: e14ab23dde12b80d ("efivars: efivar_entry API")
Reported-by: Bob Sanders &lt;bob.sanders@hpe.com&gt; and the LTP testsuite
Signed-off-by: Vladis Dronov &lt;vdronov@redhat.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200305084041.24053-2-vdronov@redhat.com
Link: https://lore.kernel.org/r/20200308080859.21568-24-ardb@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>efi: READ_ONCE rng seed size before munmap</title>
<updated>2020-02-26T14:31:43+00:00</updated>
<author>
<name>Jason A. Donenfeld</name>
<email>Jason@zx2c4.com</email>
</author>
<published>2020-02-21T08:48:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=be36f9e7517e17810ec369626a128d7948942259'/>
<id>be36f9e7517e17810ec369626a128d7948942259</id>
<content type='text'>
This function is consistent with using size instead of seed-&gt;size
(except for one place that this patch fixes), but it reads seed-&gt;size
without using READ_ONCE, which means the compiler might still do
something unwanted. So, this commit simply adds the READ_ONCE
wrapper.

Fixes: 636259880a7e ("efi: Add support for seeding the RNG from a UEFI ...")
Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: linux-efi@vger.kernel.org
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20200217123354.21140-1-Jason@zx2c4.com
Link: https://lore.kernel.org/r/20200221084849.26878-5-ardb@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This function is consistent with using size instead of seed-&gt;size
(except for one place that this patch fixes), but it reads seed-&gt;size
without using READ_ONCE, which means the compiler might still do
something unwanted. So, this commit simply adds the READ_ONCE
wrapper.

Fixes: 636259880a7e ("efi: Add support for seeding the RNG from a UEFI ...")
Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: linux-efi@vger.kernel.org
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20200217123354.21140-1-Jason@zx2c4.com
Link: https://lore.kernel.org/r/20200221084849.26878-5-ardb@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: mm: convert mm/dump.c to use walk_page_range()</title>
<updated>2020-02-04T03:05:25+00:00</updated>
<author>
<name>Steven Price</name>
<email>steven.price@arm.com</email>
</author>
<published>2020-02-04T01:36:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=102f45fdbe420f7d31182a69f4b11e8a6ae998da'/>
<id>102f45fdbe420f7d31182a69f4b11e8a6ae998da</id>
<content type='text'>
Now walk_page_range() can walk kernel page tables, we can switch the arm64
ptdump code over to using it, simplifying the code.

Link: http://lkml.kernel.org/r/20191218162402.45610-22-steven.price@arm.com
Signed-off-by: Steven Price &lt;steven.price@arm.com&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Albert Ou &lt;aou@eecs.berkeley.edu&gt;
Cc: Alexandre Ghiti &lt;alex@ghiti.fr&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Hogan &lt;jhogan@kernel.org&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Jerome Glisse &lt;jglisse@redhat.com&gt;
Cc: "Liang, Kan" &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Paul Burton &lt;paul.burton@mips.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Zong Li &lt;zong.li@sifive.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now walk_page_range() can walk kernel page tables, we can switch the arm64
ptdump code over to using it, simplifying the code.

Link: http://lkml.kernel.org/r/20191218162402.45610-22-steven.price@arm.com
Signed-off-by: Steven Price &lt;steven.price@arm.com&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Albert Ou &lt;aou@eecs.berkeley.edu&gt;
Cc: Alexandre Ghiti &lt;alex@ghiti.fr&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Hogan &lt;jhogan@kernel.org&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Jerome Glisse &lt;jglisse@redhat.com&gt;
Cc: "Liang, Kan" &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Paul Burton &lt;paul.burton@mips.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Zong Li &lt;zong.li@sifive.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
