<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include/crypto, branch linux-5.15.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>crypto: algif_aead - Revert to operating out-of-place</title>
<updated>2026-04-30T09:24:38+00:00</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2026-04-30T06:35:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=19d43105a97be0810edbda875f2cd03f30dc130c'/>
<id>19d43105a97be0810edbda875f2cd03f30dc130c</id>
<content type='text'>
commit a664bf3d603dc3bdcf9ae47cc21e0daec706d7a5 upstream.

This mostly reverts commit 72548b093ee3 except for the copying of
the associated data.

There is no benefit in operating in-place in algif_aead since the
source and destination come from different mappings.  Get rid of
all the complexity added for in-place operation and just copy the
AD directly.

Fixes: 72548b093ee3 ("crypto: algif_aead - copy AAD from src to dst")
Reported-by: Taeyang Lee &lt;0wn@theori.io&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Eric Biggers &lt;ebiggers@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 a664bf3d603dc3bdcf9ae47cc21e0daec706d7a5 upstream.

This mostly reverts commit 72548b093ee3 except for the copying of
the associated data.

There is no benefit in operating in-place in algif_aead since the
source and destination come from different mappings.  Get rid of
all the complexity added for in-place operation and just copy the
AD directly.

Fixes: 72548b093ee3 ("crypto: algif_aead - copy AAD from src to dst")
Reported-by: Taeyang Lee &lt;0wn@theori.io&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Eric Biggers &lt;ebiggers@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: scatterwalk - Backport memcpy_sglist()</title>
<updated>2026-04-30T09:24:37+00:00</updated>
<author>
<name>Eric Biggers</name>
<email>ebiggers@kernel.org</email>
</author>
<published>2026-04-30T06:35:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=36435a56cd6bab7609c3e0fd7a70224795375748'/>
<id>36435a56cd6bab7609c3e0fd7a70224795375748</id>
<content type='text'>
This backports the current implementation of memcpy_sglist() from
upstream commit 4dffc9bbffb9ccfcda730d899c97c553599e7ca8.

This function was rewritten twice.  The earlier implementations had many
prerequisite commits, while the latest implementation is standalone.
It's much easier to just backport the latest code directly.

Signed-off-by: Eric Biggers &lt;ebiggers@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>
This backports the current implementation of memcpy_sglist() from
upstream commit 4dffc9bbffb9ccfcda730d899c97c553599e7ca8.

This function was rewritten twice.  The earlier implementations had many
prerequisite commits, while the latest implementation is standalone.
It's much easier to just backport the latest code directly.

Signed-off-by: Eric Biggers &lt;ebiggers@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: af_alg - Fix incorrect boolean values in af_alg_ctx</title>
<updated>2025-10-02T11:39:13+00:00</updated>
<author>
<name>Eric Biggers</name>
<email>ebiggers@kernel.org</email>
</author>
<published>2025-09-24T20:18:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d382d6daf0184490f366562469a5673f65ee2662'/>
<id>d382d6daf0184490f366562469a5673f65ee2662</id>
<content type='text'>
[ Upstream commit d0ca0df179c4b21e2a6c4a4fb637aa8fa14575cb ]

Commit 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in
af_alg_sendmsg") changed some fields from bool to 1-bit bitfields of
type u32.

However, some assignments to these fields, specifically 'more' and
'merge', assign values greater than 1.  These relied on C's implicit
conversion to bool, such that zero becomes false and nonzero becomes
true.

With a 1-bit bitfields of type u32 instead, mod 2 of the value is taken
instead, resulting in 0 being assigned in some cases when 1 was intended.

Fix this by restoring the bool type.

Fixes: 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers &lt;ebiggers@kernel.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.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 d0ca0df179c4b21e2a6c4a4fb637aa8fa14575cb ]

Commit 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in
af_alg_sendmsg") changed some fields from bool to 1-bit bitfields of
type u32.

However, some assignments to these fields, specifically 'more' and
'merge', assign values greater than 1.  These relied on C's implicit
conversion to bool, such that zero becomes false and nonzero becomes
true.

With a 1-bit bitfields of type u32 instead, mod 2 of the value is taken
instead, resulting in 0 being assigned in some cases when 1 was intended.

Fix this by restoring the bool type.

Fixes: 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers &lt;ebiggers@kernel.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg</title>
<updated>2025-10-02T11:39:13+00:00</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2025-09-16T09:20:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e4c1ec11132ec466f7362a95f36a506ce4dc08c9'/>
<id>e4c1ec11132ec466f7362a95f36a506ce4dc08c9</id>
<content type='text'>
[ Upstream commit 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 ]

Issuing two writes to the same af_alg socket is bogus as the
data will be interleaved in an unpredictable fashion.  Furthermore,
concurrent writes may create inconsistencies in the internal
socket state.

Disallow this by adding a new ctx-&gt;write field that indiciates
exclusive ownership for writing.

Fixes: 8ff590903d5 ("crypto: algif_skcipher - User-space interface for skcipher operations")
Reported-by: Muhammad Alifa Ramdhan &lt;ramdhan@starlabs.sg&gt;
Reported-by: Bing-Jhong Billy Jheng &lt;billy@starlabs.sg&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&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 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 ]

Issuing two writes to the same af_alg socket is bogus as the
data will be interleaved in an unpredictable fashion.  Furthermore,
concurrent writes may create inconsistencies in the internal
socket state.

Disallow this by adding a new ctx-&gt;write field that indiciates
exclusive ownership for writing.

Fixes: 8ff590903d5 ("crypto: algif_skcipher - User-space interface for skcipher operations")
Reported-by: Muhammad Alifa Ramdhan &lt;ramdhan@starlabs.sg&gt;
Reported-by: Bing-Jhong Billy Jheng &lt;billy@starlabs.sg&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: af_alg - Disallow multiple in-flight AIO requests</title>
<updated>2024-01-25T22:52:34+00:00</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2023-11-28T08:25:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d2205b9b57b91f4242fb9210df798ca76048f98b'/>
<id>d2205b9b57b91f4242fb9210df798ca76048f98b</id>
<content type='text'>
[ Upstream commit 67b164a871af1d736f131fd6fe78a610909f06f3 ]

Having multiple in-flight AIO requests results in unpredictable
output because they all share the same IV.  Fix this by only allowing
one request at a time.

Fixes: 83094e5e9e49 ("crypto: af_alg - add async support to algif_aead")
Fixes: a596999b7ddf ("crypto: algif - change algif_skcipher to be asynchronous")
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&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 67b164a871af1d736f131fd6fe78a610909f06f3 ]

Having multiple in-flight AIO requests results in unpredictable
output because they all share the same IV.  Fix this by only allowing
one request at a time.

Fixes: 83094e5e9e49 ("crypto: af_alg - add async support to algif_aead")
Fixes: a596999b7ddf ("crypto: algif - change algif_skcipher to be asynchronous")
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: api - Use work queue in crypto_destroy_instance</title>
<updated>2023-09-19T10:22:33+00:00</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2023-08-03T09:59:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=048545d9fc6424b0a11e7e8771225bb9afe09422'/>
<id>048545d9fc6424b0a11e7e8771225bb9afe09422</id>
<content type='text'>
[ Upstream commit 9ae4577bc077a7e32c3c7d442c95bc76865c0f17 ]

The function crypto_drop_spawn expects to be called in process
context.  However, when an instance is unregistered while it still
has active users, the last user may cause the instance to be freed
in atomic context.

Fix this by delaying the freeing to a work queue.

Fixes: 6bfd48096ff8 ("[CRYPTO] api: Added spawns")
Reported-by: Florent Revest &lt;revest@chromium.org&gt;
Reported-by: syzbot+d769eed29cc42d75e2a3@syzkaller.appspotmail.com
Reported-by: syzbot+610ec0671f51e838436e@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Tested-by: Florent Revest &lt;revest@chromium.org&gt;
Acked-by: Florent Revest &lt;revest@chromium.org&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&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 9ae4577bc077a7e32c3c7d442c95bc76865c0f17 ]

The function crypto_drop_spawn expects to be called in process
context.  However, when an instance is unregistered while it still
has active users, the last user may cause the instance to be freed
in atomic context.

Fix this by delaying the freeing to a work queue.

Fixes: 6bfd48096ff8 ("[CRYPTO] api: Added spawns")
Reported-by: Florent Revest &lt;revest@chromium.org&gt;
Reported-by: syzbot+d769eed29cc42d75e2a3@syzkaller.appspotmail.com
Reported-by: syzbot+610ec0671f51e838436e@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Tested-by: Florent Revest &lt;revest@chromium.org&gt;
Acked-by: Florent Revest &lt;revest@chromium.org&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: kpp - Add helper to set reqsize</title>
<updated>2023-07-23T11:47:16+00:00</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2022-11-22T09:24:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=30682e121475e50b4cc9e511ad0778f46a0fd618'/>
<id>30682e121475e50b4cc9e511ad0778f46a0fd618</id>
<content type='text'>
[ Upstream commit 56861cbde1b9f3b34d300e6ba87f2c3de1a9c309 ]

The value of reqsize should only be changed through a helper.
To do so we need to first add a helper for this.

Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Stable-dep-of: eb7713f5ca97 ("crypto: qat - unmap buffer before free for DH")
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 56861cbde1b9f3b34d300e6ba87f2c3de1a9c309 ]

The value of reqsize should only be changed through a helper.
To do so we need to first add a helper for this.

Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Stable-dep-of: eb7713f5ca97 ("crypto: qat - unmap buffer before free for DH")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: api - Add scaffolding to change completion function signature</title>
<updated>2023-05-17T09:50:20+00:00</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2023-01-31T08:01:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e7ce4ba11635ef23aa7ad40b4b9f9c52ef15f9e2'/>
<id>e7ce4ba11635ef23aa7ad40b4b9f9c52ef15f9e2</id>
<content type='text'>
[ Upstream commit c35e03eaece71101ff6cbf776b86403860ac8cc3 ]

The crypto completion function currently takes a pointer to a
struct crypto_async_request object.  However, in reality the API
does not allow the use of any part of the object apart from the
data field.  For example, ahash/shash will create a fake object
on the stack to pass along a different data field.

This leads to potential bugs where the user may try to dereference
or otherwise use the crypto_async_request object.

This patch adds some temporary scaffolding so that the completion
function can take a void * instead.  Once affected users have been
converted this can be removed.

The helper crypto_request_complete will remain even after the
conversion is complete.  It should be used instead of calling
the completion function directly.

Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Reviewed-by: Giovanni Cabiddu &lt;giovanni.cabiddu@intel.com&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Stable-dep-of: 4140aafcff16 ("crypto: engine - fix crypto_queue backlog handling")
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 c35e03eaece71101ff6cbf776b86403860ac8cc3 ]

The crypto completion function currently takes a pointer to a
struct crypto_async_request object.  However, in reality the API
does not allow the use of any part of the object apart from the
data field.  For example, ahash/shash will create a fake object
on the stack to pass along a different data field.

This leads to potential bugs where the user may try to dereference
or otherwise use the crypto_async_request object.

This patch adds some temporary scaffolding so that the completion
function can take a void * instead.  Once affected users have been
converted this can be removed.

The helper crypto_request_complete will remain even after the
conversion is complete.  It should be used instead of calling
the completion function directly.

Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Reviewed-by: Giovanni Cabiddu &lt;giovanni.cabiddu@intel.com&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Stable-dep-of: 4140aafcff16 ("crypto: engine - fix crypto_queue backlog handling")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: blake2s - remove shash module</title>
<updated>2022-08-17T12:24:19+00:00</updated>
<author>
<name>Jason A. Donenfeld</name>
<email>Jason@zx2c4.com</email>
</author>
<published>2022-05-28T19:44:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3dd33a09f5dc12ccb0902923c4c784eb0f8c7554'/>
<id>3dd33a09f5dc12ccb0902923c4c784eb0f8c7554</id>
<content type='text'>
[ Upstream commit 2d16803c562ecc644803d42ba98a8e0aef9c014e ]

BLAKE2s has no currently known use as an shash. Just remove all of this
unnecessary plumbing. Removing this shash was something we talked about
back when we were making BLAKE2s a built-in, but I simply never got
around to doing it. So this completes that project.

Importantly, this fixs a bug in which the lib code depends on
crypto_simd_disabled_for_test, causing linker errors.

Also add more alignment tests to the selftests and compare SIMD and
non-SIMD compression functions, to make up for what we lose from
testmgr.c.

Reported-by: gaochao &lt;gaochao49@huawei.com&gt;
Cc: Eric Biggers &lt;ebiggers@kernel.org&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: stable@vger.kernel.org
Fixes: 6048fdcc5f26 ("lib/crypto: blake2s: include as built-in")
Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&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 2d16803c562ecc644803d42ba98a8e0aef9c014e ]

BLAKE2s has no currently known use as an shash. Just remove all of this
unnecessary plumbing. Removing this shash was something we talked about
back when we were making BLAKE2s a built-in, but I simply never got
around to doing it. So this completes that project.

Importantly, this fixs a bug in which the lib code depends on
crypto_simd_disabled_for_test, causing linker errors.

Also add more alignment tests to the selftests and compare SIMD and
non-SIMD compression functions, to make up for what we lose from
testmgr.c.

Reported-by: gaochao &lt;gaochao49@huawei.com&gt;
Cc: Eric Biggers &lt;ebiggers@kernel.org&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: stable@vger.kernel.org
Fixes: 6048fdcc5f26 ("lib/crypto: blake2s: include as built-in")
Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: drbg - make reseeding from get_random_bytes() synchronous</title>
<updated>2022-06-06T06:43:38+00:00</updated>
<author>
<name>Nicolai Stange</name>
<email>nstange@suse.de</email>
</author>
<published>2022-06-02T20:23:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e61717947af57fd6751e1e79d4179f561dfc6149'/>
<id>e61717947af57fd6751e1e79d4179f561dfc6149</id>
<content type='text'>
commit 074bcd4000e0d812bc253f86fedc40f81ed59ccc upstream.

get_random_bytes() usually hasn't full entropy available by the time DRBG
instances are first getting seeded from it during boot. Thus, the DRBG
implementation registers random_ready_callbacks which would in turn
schedule some work for reseeding the DRBGs once get_random_bytes() has
sufficient entropy available.

For reference, the relevant history around handling DRBG (re)seeding in
the context of a not yet fully seeded get_random_bytes() is:

  commit 16b369a91d0d ("random: Blocking API for accessing
                        nonblocking_pool")
  commit 4c7879907edd ("crypto: drbg - add async seeding operation")

  commit 205a525c3342 ("random: Add callback API for random pool
                        readiness")
  commit 57225e679788 ("crypto: drbg - Use callback API for random
                        readiness")
  commit c2719503f5e1 ("random: Remove kernel blocking API")

However, some time later, the initialization state of get_random_bytes()
has been made queryable via rng_is_initialized() introduced with commit
9a47249d444d ("random: Make crng state queryable"). This primitive now
allows for streamlining the DRBG reseeding from get_random_bytes() by
replacing that aforementioned asynchronous work scheduling from
random_ready_callbacks with some simpler, synchronous code in
drbg_generate() next to the related logic already present therein. Apart
from improving overall code readability, this change will also enable DRBG
users to rely on wait_for_random_bytes() for ensuring that the initial
seeding has completed, if desired.

The previous patches already laid the grounds by making drbg_seed() to
record at each DRBG instance whether it was being seeded at a time when
rng_is_initialized() still had been false as indicated by
-&gt;seeded == DRBG_SEED_STATE_PARTIAL.

All that remains to be done now is to make drbg_generate() check for this
condition, determine whether rng_is_initialized() has flipped to true in
the meanwhile and invoke a reseed from get_random_bytes() if so.

Make this move:
- rename the former drbg_async_seed() work handler, i.e. the one in charge
  of reseeding a DRBG instance from get_random_bytes(), to
  "drbg_seed_from_random()",
- change its signature as appropriate, i.e. make it take a struct
  drbg_state rather than a work_struct and change its return type from
  "void" to "int" in order to allow for passing error information from
  e.g. its __drbg_seed() invocation onwards to callers,
- make drbg_generate() invoke this drbg_seed_from_random() once it
  encounters a DRBG instance with -&gt;seeded == DRBG_SEED_STATE_PARTIAL by
  the time rng_is_initialized() has flipped to true and
- prune everything related to the former, random_ready_callback based
  mechanism.

As drbg_seed_from_random() is now getting invoked from drbg_generate() with
the -&gt;drbg_mutex being held, it must not attempt to recursively grab it
once again. Remove the corresponding mutex operations from what is now
drbg_seed_from_random(). Furthermore, as drbg_seed_from_random() can now
report errors directly to its caller, there's no need for it to temporarily
switch the DRBG's -&gt;seeded state to DRBG_SEED_STATE_UNSEEDED so that a
failure of the subsequently invoked __drbg_seed() will get signaled to
drbg_generate(). Don't do it then.

Signed-off-by: Nicolai Stange &lt;nstange@suse.de&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
[Jason: for stable, undid the modifications for the backport of 5acd3548.]
Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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<pre>
commit 074bcd4000e0d812bc253f86fedc40f81ed59ccc upstream.

get_random_bytes() usually hasn't full entropy available by the time DRBG
instances are first getting seeded from it during boot. Thus, the DRBG
implementation registers random_ready_callbacks which would in turn
schedule some work for reseeding the DRBGs once get_random_bytes() has
sufficient entropy available.

For reference, the relevant history around handling DRBG (re)seeding in
the context of a not yet fully seeded get_random_bytes() is:

  commit 16b369a91d0d ("random: Blocking API for accessing
                        nonblocking_pool")
  commit 4c7879907edd ("crypto: drbg - add async seeding operation")

  commit 205a525c3342 ("random: Add callback API for random pool
                        readiness")
  commit 57225e679788 ("crypto: drbg - Use callback API for random
                        readiness")
  commit c2719503f5e1 ("random: Remove kernel blocking API")

However, some time later, the initialization state of get_random_bytes()
has been made queryable via rng_is_initialized() introduced with commit
9a47249d444d ("random: Make crng state queryable"). This primitive now
allows for streamlining the DRBG reseeding from get_random_bytes() by
replacing that aforementioned asynchronous work scheduling from
random_ready_callbacks with some simpler, synchronous code in
drbg_generate() next to the related logic already present therein. Apart
from improving overall code readability, this change will also enable DRBG
users to rely on wait_for_random_bytes() for ensuring that the initial
seeding has completed, if desired.

The previous patches already laid the grounds by making drbg_seed() to
record at each DRBG instance whether it was being seeded at a time when
rng_is_initialized() still had been false as indicated by
-&gt;seeded == DRBG_SEED_STATE_PARTIAL.

All that remains to be done now is to make drbg_generate() check for this
condition, determine whether rng_is_initialized() has flipped to true in
the meanwhile and invoke a reseed from get_random_bytes() if so.

Make this move:
- rename the former drbg_async_seed() work handler, i.e. the one in charge
  of reseeding a DRBG instance from get_random_bytes(), to
  "drbg_seed_from_random()",
- change its signature as appropriate, i.e. make it take a struct
  drbg_state rather than a work_struct and change its return type from
  "void" to "int" in order to allow for passing error information from
  e.g. its __drbg_seed() invocation onwards to callers,
- make drbg_generate() invoke this drbg_seed_from_random() once it
  encounters a DRBG instance with -&gt;seeded == DRBG_SEED_STATE_PARTIAL by
  the time rng_is_initialized() has flipped to true and
- prune everything related to the former, random_ready_callback based
  mechanism.

As drbg_seed_from_random() is now getting invoked from drbg_generate() with
the -&gt;drbg_mutex being held, it must not attempt to recursively grab it
once again. Remove the corresponding mutex operations from what is now
drbg_seed_from_random(). Furthermore, as drbg_seed_from_random() can now
report errors directly to its caller, there's no need for it to temporarily
switch the DRBG's -&gt;seeded state to DRBG_SEED_STATE_UNSEEDED so that a
failure of the subsequently invoked __drbg_seed() will get signaled to
drbg_generate(). Don't do it then.

Signed-off-by: Nicolai Stange &lt;nstange@suse.de&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
[Jason: for stable, undid the modifications for the backport of 5acd3548.]
Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
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