Hi Herbert,
I have found a regression in userspace behaviour after this patch was
merged into the 4.19.y kernel. The fix seems to involve backporting a
few more changes. Could you review details below and confirm if this is
the right approach?
On Tue, Nov 28, 2023 at 04:25:49PM +0800, Herbert Xu wrote:
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 <herbert@xxxxxxxxxxxxxxxxxxx>
---
crypto/af_alg.c | 14 +++++++++++++-
include/crypto/if_alg.h | 3 +++
2 files changed, 16 insertions(+), 1 deletion(-)
This change got backported on the 4.19 kernel in January:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.19.y&id=19af0310c8767c993f2a5d5261e4df3f9f465ce1
Since then, I am seeing a regression in a simple openssl encoding test:
openssl enc -k mysecret -aes-256-cbc -in plain.txt -out cipher.txt -engine afalg
It fails intermittently with the message "error writing to file", but
this error is a bit misleading, the actual problem is that the kernel
returns -16 (EBUSY) on the encoding operation.
This happens only in 4.19, and not under 5.10. The patch seems correct,
however it seems we are missing a couple of other patches on 4.19:
f3c802a1f3001 crypto: algif_aead - Only wake up when ctx->more is zero
21dfbcd1f5cbf crypto: algif_aead - fix uninitialized ctx->init
I was able to cherry-pick those into 4.19.y, with just a minor conflict
in one case. With those applied, the openssl command no longer fails.
I suspect similar changes would be needed also in 5.4 kernel, however I
neither checked that, nor have I run any tests on that version.
Regards,
-Ralph
