FAILED: patch "[PATCH] crypto: qat - validate RSA CRT component lengths" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x b3ac78756588059729b9195fcc9f4b37d54057a5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071550-encrypt-hypnotist-52ba@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b3ac78756588059729b9195fcc9f4b37d54057a5 Mon Sep 17 00:00:00 2001
From: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Date: Thu, 28 May 2026 16:57:44 +0100
Subject: [PATCH] crypto: qat - validate RSA CRT component lengths

The generic RSA key parser (rsa_helper.c) bounds each CRT component (p,
q, dp, dq, qinv) by the modulus size n_sz, but qat_rsa_setkey_crt()
allocates half-size DMA buffers (key_sz / 2) and right-aligns each
component with:

    memcpy(dst + half_key_sz - len, src, len)

When a CRT component is larger than half_key_sz the subtraction
underflows and memcpy writes past the DMA buffer, causing memory
corruption.

Add a len > half_key_sz check next to the existing !len check for each
of the five CRT components so the driver falls back to the non-CRT path
instead of writing out of bounds.

Fixes: 879f77e9071f ("crypto: qat - Add RSA CRT mode")
Cc: stable@vger.kernel.org
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Ahsan Atta <ahsan.atta@intel.com>
Reviewed-by: Laurent M Coquerel <laurent.m.coquerel@intel.com>
Tested-by: Laurent M Coquerel <laurent.m.coquerel@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/intel/qat/qat_common/qat_asym_algs.c b/drivers/crypto/intel/qat/qat_common/qat_asym_algs.c
index e09b9edfce42..75c15c8e41db 100644
--- a/drivers/crypto/intel/qat/qat_common/qat_asym_algs.c
+++ b/drivers/crypto/intel/qat/qat_common/qat_asym_algs.c
@@ -1085,7 +1085,7 @@ static void qat_rsa_setkey_crt(struct qat_rsa_ctx *ctx, struct rsa_key *rsa_key)
 	ptr = rsa_key->p;
 	len = rsa_key->p_sz;
 	qat_rsa_drop_leading_zeros(&ptr, &len);
-	if (!len)
+	if (!len || len > half_key_sz)
 		goto err;
 	ctx->p = dma_alloc_coherent(dev, half_key_sz, &ctx->dma_p, GFP_KERNEL);
 	if (!ctx->p)
@@ -1096,7 +1096,7 @@ static void qat_rsa_setkey_crt(struct qat_rsa_ctx *ctx, struct rsa_key *rsa_key)
 	ptr = rsa_key->q;
 	len = rsa_key->q_sz;
 	qat_rsa_drop_leading_zeros(&ptr, &len);
-	if (!len)
+	if (!len || len > half_key_sz)
 		goto free_p;
 	ctx->q = dma_alloc_coherent(dev, half_key_sz, &ctx->dma_q, GFP_KERNEL);
 	if (!ctx->q)
@@ -1107,7 +1107,7 @@ static void qat_rsa_setkey_crt(struct qat_rsa_ctx *ctx, struct rsa_key *rsa_key)
 	ptr = rsa_key->dp;
 	len = rsa_key->dp_sz;
 	qat_rsa_drop_leading_zeros(&ptr, &len);
-	if (!len)
+	if (!len || len > half_key_sz)
 		goto free_q;
 	ctx->dp = dma_alloc_coherent(dev, half_key_sz, &ctx->dma_dp,
 				     GFP_KERNEL);
@@ -1119,7 +1119,7 @@ static void qat_rsa_setkey_crt(struct qat_rsa_ctx *ctx, struct rsa_key *rsa_key)
 	ptr = rsa_key->dq;
 	len = rsa_key->dq_sz;
 	qat_rsa_drop_leading_zeros(&ptr, &len);
-	if (!len)
+	if (!len || len > half_key_sz)
 		goto free_dp;
 	ctx->dq = dma_alloc_coherent(dev, half_key_sz, &ctx->dma_dq,
 				     GFP_KERNEL);
@@ -1131,7 +1131,7 @@ static void qat_rsa_setkey_crt(struct qat_rsa_ctx *ctx, struct rsa_key *rsa_key)
 	ptr = rsa_key->qinv;
 	len = rsa_key->qinv_sz;
 	qat_rsa_drop_leading_zeros(&ptr, &len);
-	if (!len)
+	if (!len || len > half_key_sz)
 		goto free_dq;
 	ctx->qinv = dma_alloc_coherent(dev, half_key_sz, &ctx->dma_qinv,
 				       GFP_KERNEL);