diff mbox series

[6.1.y] net: tls: handle backlogging of crypto requests

Message ID 20240328123805.3886026-1-srish.srinivasan@broadcom.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [6.1.y] net: tls: handle backlogging of crypto requests | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Srish Srinivasan March 28, 2024, 12:38 p.m. UTC
From: Jakub Kicinski <kuba@kernel.org>

commit 8590541473188741055d27b955db0777569438e3 upstream

Since we're setting the CRYPTO_TFM_REQ_MAY_BACKLOG flag on our
requests to the crypto API, crypto_aead_{encrypt,decrypt} can return
 -EBUSY instead of -EINPROGRESS in valid situations. For example, when
the cryptd queue for AESNI is full (easy to trigger with an
artificially low cryptd.cryptd_max_cpu_qlen), requests will be enqueued
to the backlog but still processed. In that case, the async callback
will also be called twice: first with err == -EINPROGRESS, which it
seems we can just ignore, then with err == 0.

Compared to Sabrina's original patch this version uses the new
tls_*crypt_async_wait() helpers and converts the EBUSY to
EINPROGRESS to avoid having to modify all the error handling
paths. The handling is identical.

Fixes: a54667f6728c ("tls: Add support for encryption using async offload accelerator")
Fixes: 94524d8fc965 ("net/tls: Add support for async decryption of tls records")
Co-developed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/netdev/9681d1febfec295449a62300938ed2ae66983f28.1694018970.git.sd@queasysnail.net/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[Srish: fixed merge-conflict in stable branch linux-6.1.y,
needs to go on top of https://lore.kernel.org/stable/20240307155930.913525-1-lee@kernel.org/]
Signed-off-by: Srish Srinivasan <srish.srinivasan@broadcom.com>
---
 net/tls/tls_sw.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Comments

Greg Kroah-Hartman March 29, 2024, 9:23 a.m. UTC | #1
On Thu, Mar 28, 2024 at 06:08:05PM +0530, Srish Srinivasan wrote:
> From: Jakub Kicinski <kuba@kernel.org>
> 
> commit 8590541473188741055d27b955db0777569438e3 upstream
> 
> Since we're setting the CRYPTO_TFM_REQ_MAY_BACKLOG flag on our
> requests to the crypto API, crypto_aead_{encrypt,decrypt} can return
>  -EBUSY instead of -EINPROGRESS in valid situations. For example, when
> the cryptd queue for AESNI is full (easy to trigger with an
> artificially low cryptd.cryptd_max_cpu_qlen), requests will be enqueued
> to the backlog but still processed. In that case, the async callback
> will also be called twice: first with err == -EINPROGRESS, which it
> seems we can just ignore, then with err == 0.
> 
> Compared to Sabrina's original patch this version uses the new
> tls_*crypt_async_wait() helpers and converts the EBUSY to
> EINPROGRESS to avoid having to modify all the error handling
> paths. The handling is identical.
> 
> Fixes: a54667f6728c ("tls: Add support for encryption using async offload accelerator")
> Fixes: 94524d8fc965 ("net/tls: Add support for async decryption of tls records")
> Co-developed-by: Sabrina Dubroca <sd@queasysnail.net>
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> Link: https://lore.kernel.org/netdev/9681d1febfec295449a62300938ed2ae66983f28.1694018970.git.sd@queasysnail.net/
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> Reviewed-by: Simon Horman <horms@kernel.org>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> [Srish: fixed merge-conflict in stable branch linux-6.1.y,
> needs to go on top of https://lore.kernel.org/stable/20240307155930.913525-1-lee@kernel.org/]
> Signed-off-by: Srish Srinivasan <srish.srinivasan@broadcom.com>
> ---
>  net/tls/tls_sw.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)

Now queued up, thanks.

greg k-h
Srish Srinivasan March 29, 2024, 10:32 a.m. UTC | #2
On Fri, Mar 29, 2024 at 2:53 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Thu, Mar 28, 2024 at 06:08:05PM +0530, Srish Srinivasan wrote:
> > From: Jakub Kicinski <kuba@kernel.org>
> >
> > commit 8590541473188741055d27b955db0777569438e3 upstream
> >
> > Since we're setting the CRYPTO_TFM_REQ_MAY_BACKLOG flag on our
> > requests to the crypto API, crypto_aead_{encrypt,decrypt} can return
> >  -EBUSY instead of -EINPROGRESS in valid situations. For example, when
> > the cryptd queue for AESNI is full (easy to trigger with an
> > artificially low cryptd.cryptd_max_cpu_qlen), requests will be enqueued
> > to the backlog but still processed. In that case, the async callback
> > will also be called twice: first with err == -EINPROGRESS, which it
> > seems we can just ignore, then with err == 0.
> >
> > Compared to Sabrina's original patch this version uses the new
> > tls_*crypt_async_wait() helpers and converts the EBUSY to
> > EINPROGRESS to avoid having to modify all the error handling
> > paths. The handling is identical.
> >
> > Fixes: a54667f6728c ("tls: Add support for encryption using async offload accelerator")
> > Fixes: 94524d8fc965 ("net/tls: Add support for async decryption of tls records")
> > Co-developed-by: Sabrina Dubroca <sd@queasysnail.net>
> > Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> > Link: https://lore.kernel.org/netdev/9681d1febfec295449a62300938ed2ae66983f28.1694018970.git.sd@queasysnail.net/
> > Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> > Reviewed-by: Simon Horman <horms@kernel.org>
> > Signed-off-by: David S. Miller <davem@davemloft.net>
> > Signed-off-by: Sasha Levin <sashal@kernel.org>
> > [Srish: fixed merge-conflict in stable branch linux-6.1.y,
> > needs to go on top of https://lore.kernel.org/stable/20240307155930.913525-1-lee@kernel.org/]
> > Signed-off-by: Srish Srinivasan <srish.srinivasan@broadcom.com>
> > ---
> >  net/tls/tls_sw.c | 22 ++++++++++++++++++++++
> >  1 file changed, 22 insertions(+)
>
> Now queued up, thanks.
>

Greg, this patch (i.e. v1) has hunk failures.

Just now I have sent v2 for this patch (after resolving hunks).
Requesting you to queue up v2:
https://lore.kernel.org/stable/20240329102540.3888561-1-srish.srinivasan@broadcom.com/T/#m164567a5bd32085931a1b1367ae12e4102870111

Sorry for the inconvenience.

> greg k-h
Greg Kroah-Hartman March 29, 2024, 11:48 a.m. UTC | #3
On Fri, Mar 29, 2024 at 04:02:57PM +0530, Srish Srinivasan wrote:
> On Fri, Mar 29, 2024 at 2:53 PM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Thu, Mar 28, 2024 at 06:08:05PM +0530, Srish Srinivasan wrote:
> > > From: Jakub Kicinski <kuba@kernel.org>
> > >
> > > commit 8590541473188741055d27b955db0777569438e3 upstream
> > >
> > > Since we're setting the CRYPTO_TFM_REQ_MAY_BACKLOG flag on our
> > > requests to the crypto API, crypto_aead_{encrypt,decrypt} can return
> > >  -EBUSY instead of -EINPROGRESS in valid situations. For example, when
> > > the cryptd queue for AESNI is full (easy to trigger with an
> > > artificially low cryptd.cryptd_max_cpu_qlen), requests will be enqueued
> > > to the backlog but still processed. In that case, the async callback
> > > will also be called twice: first with err == -EINPROGRESS, which it
> > > seems we can just ignore, then with err == 0.
> > >
> > > Compared to Sabrina's original patch this version uses the new
> > > tls_*crypt_async_wait() helpers and converts the EBUSY to
> > > EINPROGRESS to avoid having to modify all the error handling
> > > paths. The handling is identical.
> > >
> > > Fixes: a54667f6728c ("tls: Add support for encryption using async offload accelerator")
> > > Fixes: 94524d8fc965 ("net/tls: Add support for async decryption of tls records")
> > > Co-developed-by: Sabrina Dubroca <sd@queasysnail.net>
> > > Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> > > Link: https://lore.kernel.org/netdev/9681d1febfec295449a62300938ed2ae66983f28.1694018970.git.sd@queasysnail.net/
> > > Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> > > Reviewed-by: Simon Horman <horms@kernel.org>
> > > Signed-off-by: David S. Miller <davem@davemloft.net>
> > > Signed-off-by: Sasha Levin <sashal@kernel.org>
> > > [Srish: fixed merge-conflict in stable branch linux-6.1.y,
> > > needs to go on top of https://lore.kernel.org/stable/20240307155930.913525-1-lee@kernel.org/]
> > > Signed-off-by: Srish Srinivasan <srish.srinivasan@broadcom.com>
> > > ---
> > >  net/tls/tls_sw.c | 22 ++++++++++++++++++++++
> > >  1 file changed, 22 insertions(+)
> >
> > Now queued up, thanks.
> >
> 
> Greg, this patch (i.e. v1) has hunk failures.

What do you mean?  it worked here just fine.

> Just now I have sent v2 for this patch (after resolving hunks).
> Requesting you to queue up v2:
> https://lore.kernel.org/stable/20240329102540.3888561-1-srish.srinivasan@broadcom.com/T/#m164567a5bd32085931a1b1367ae12e4102870111

Let me see what the actual difference is...
Oleksandr Tymoshenko May 21, 2024, 10:58 a.m. UTC | #4
Hello,

As far as I understand this issue also affects kernel 5.15. Are there any plans
to backport it to 5.15?

Thank you
Greg Kroah-Hartman May 21, 2024, 3:26 p.m. UTC | #5
On Tue, May 21, 2024 at 10:58:38AM +0000, Oleksandr Tymoshenko wrote:
> Hello,
> 
> As far as I understand this issue also affects kernel 5.15. Are there any plans
> to backport it to 5.15?

Why not provide a working backport if you are interested in the 5.15.y
kernel tree?

thanks,

greg k-h
diff mbox series

Patch

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 2bd27b777..61b01dfc6 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -195,6 +195,17 @@  static void tls_decrypt_done(crypto_completion_data_t *data, int err)
 	struct sock *sk;
 	int aead_size;
 
+	/* If requests get too backlogged crypto API returns -EBUSY and calls
+	 * ->complete(-EINPROGRESS) immediately followed by ->complete(0)
+	 * to make waiting for backlog to flush with crypto_wait_req() easier.
+	 * First wait converts -EBUSY -> -EINPROGRESS, and the second one
+	 * -EINPROGRESS -> 0.
+	 * We have a single struct crypto_async_request per direction, this
+	 * scheme doesn't help us, so just ignore the first ->complete().
+	 */
+	if (err == -EINPROGRESS)
+		return;
+
 	aead_size = sizeof(*aead_req) + crypto_aead_reqsize(aead);
 	aead_size = ALIGN(aead_size, __alignof__(*dctx));
 	dctx = (void *)((u8 *)aead_req + aead_size);
@@ -268,6 +279,10 @@  static int tls_do_decryption(struct sock *sk,
 	}
 
 	ret = crypto_aead_decrypt(aead_req);
+	if (ret == -EBUSY) {
+		ret = tls_decrypt_async_wait(ctx);
+		ret = ret ?: -EINPROGRESS;
+	}
 	if (ret == -EINPROGRESS) {
 		if (darg->async)
 			return 0;
@@ -452,6 +467,9 @@  static void tls_encrypt_done(crypto_completion_data_t *data, int err)
 	bool ready = false;
 	struct sock *sk;
 
+	if (err == -EINPROGRESS) /* see the comment in tls_decrypt_done() */
+		return;
+
 	rec = container_of(aead_req, struct tls_rec, aead_req);
 	msg_en = &rec->msg_encrypted;
 
@@ -560,6 +578,10 @@  static int tls_do_encryption(struct sock *sk,
 	atomic_inc(&ctx->encrypt_pending);
 
 	rc = crypto_aead_encrypt(aead_req);
+	if (rc == -EBUSY) {
+		rc = tls_encrypt_async_wait(ctx);
+		rc = rc ?: -EINPROGRESS;
+	}
 	if (!rc || rc != -EINPROGRESS) {
 		atomic_dec(&ctx->encrypt_pending);
 		sge->offset -= prot->prepend_size;