[lts9.4] CVE-2026-31431

[roxanan1996]

jira VULN-181880
cve CVE-2026-31431
commit-author Herbert Xu herbert@gondor.apana.org.au commit a664bf3
upstream-diff |
This kernel lacks upstream commits c1abe6f ("crypto: af_alg:
Use extract_iter_to_sg() to create scatterlists") and f2804d0
("crypto: algif_aead - use memcpy_sglist() instead of null
skcipher"). As a result, there are two conflicts: the scatterlist
table is located in a different member of struct af_alg_sgl and
the null skcipher is used for copying between scatterlists instead
of memcpy_sglist() (which is a helper that doesn't exist in this
kernel version).

The scatterlist table discrepancy is resolved by using the correct
member of `struct af_alg_sgl`.

The upstream patch's usage of memcpy_sglist() is replaced by a call
to the null skcipher to perform the scatterlist copy instead.

This mostly reverts commit 72548b0 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: 72548b0 ("crypto: algif_aead - copy AAD from src to dst")
Reported-by: Taeyang Lee 0wn@theori.io
Signed-off-by: Herbert Xu herbert@gondor.apana.org.au
(cherry picked from commit a664bf3)
Signed-off-by: Sultan Alsawaf sultan@ciq.com

[github-actions]

🤖 Validation Checks In Progress Workflow run: https://github.com/ctrliq/kernel-src-tree/actions/runs/25160821506

[github-actions]

🔍 Interdiff Analysis

• ⚠️ PR commit 0807276fc6c (crypto: algif_aead - Revert to operating out-of-place) → upstream a664bf3d603d
  Differences found:

================================================================================
*    DELTA DIFFERENCES - code changes that differ between the patches          *
================================================================================

--- b/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -207,13 +208,72 @@
 	/* Use the RX SGL as source (and destination) for crypto op. */
 	rsgl_src = areq->first_rsgl.sgl.sg;
 
-	err = crypto_aead_copy_sgl(null_tfm, tsgl_src, rsgl_src,
-				   ctx->aead_assoclen);
-	if (err)
-		goto free;
+	if (ctx->enc) {
+		/*
+		 * Encryption operation - The in-place cipher operation is
+		 * achieved by the following operation:
+		 *
+		 * TX SGL: AAD || PT
+		 *	    |	   |
+		 *	    | copy |
+		 *	    v	   v
+		 * RX SGL: AAD || PT || Tag
+		 */
+		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
+					   areq->first_rsgl.sgl.sg, processed);
+		if (err)
+			goto free;
+		af_alg_pull_tsgl(sk, processed, NULL, 0);
+	} else {
+		/*
+		 * Decryption operation - To achieve an in-place cipher
+		 * operation, the following  SGL structure is used:
+		 *
+		 * TX SGL: AAD || CT || Tag
+		 *	    |	   |	 ^
+		 *	    | copy |	 | Create SGL link.
+		 *	    v	   v	 |
+		 * RX SGL: AAD || CT ----+
+		 */
+
+		 /* Copy AAD || CT to RX SGL buffer for in-place operation. */
+		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
+					   areq->first_rsgl.sgl.sg, outlen);
+		if (err)
+			goto free;
+
+		/* Create TX SGL for tag and chain it to RX SGL. */
+		areq->tsgl_entries = af_alg_count_tsgl(sk, processed,
+						       processed - as);
+		if (!areq->tsgl_entries)
+			areq->tsgl_entries = 1;
+		areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
+							 areq->tsgl_entries),
+					  GFP_KERNEL);
+		if (!areq->tsgl) {
+			err = -ENOMEM;
+			goto free;
+		}
+		sg_init_table(areq->tsgl, areq->tsgl_entries);
+
+		/* Release TX SGL, except for tag data and reassign tag data. */
+		af_alg_pull_tsgl(sk, processed, areq->tsgl, processed - as);
+
+		/* chain the areq TX SGL holding the tag with RX SGL */
+		if (usedpages) {
+			/* RX SGL present */
+			struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
+
+			sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
+			sg_chain(sgl_prev->sg, sgl_prev->npages + 1,
+				 areq->tsgl);
+		} else
+			/* no RX SGL present (e.g. authentication only) */
+			rsgl_src = areq->tsgl;
+	}
 
 	/* Initialize the crypto operation */
-	aead_request_set_crypt(&areq->cra_u.aead_req, tsgl_src,
+	aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
 			       areq->first_rsgl.sgl.sg, used, ctx->iv);
 	aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
 	aead_request_set_tfm(&areq->cra_u.aead_req, tfm);

################################################################################
!    REJECTED PATCH2 HUNKS - could not be compared; manual review needed       !
################################################################################

--- b/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -26,7 +26,6 @@
 #include <crypto/internal/aead.h>
 #include <crypto/scatterwalk.h>
 #include <crypto/if_alg.h>
-#include <crypto/skcipher.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/kernel.h>
@@ -72,7 +71,7 @@
 	struct alg_sock *pask = alg_sk(psk);
 	struct af_alg_ctx *ctx = ask->private;
 	struct crypto_aead *tfm = pask->private;
-	unsigned int i, as = crypto_aead_authsize(tfm);
+	unsigned int as = crypto_aead_authsize(tfm);
 	struct af_alg_async_req *areq;
 	struct af_alg_tsgl *tsgl, *tmp;
 	struct scatterlist *rsgl_src, *tsgl_src = NULL;
@@ -182,64 +177,7 @@
 	/* Use the RX SGL as source (and destination) for crypto op. */
 	rsgl_src = areq->first_rsgl.sgl.sgt.sgl;
 
-	if (ctx->enc) {
-		/*
-		 * Encryption operation - The in-place cipher operation is
-		 * achieved by the following operation:
-		 *
-		 * TX SGL: AAD || PT
-		 *	    |	   |
-		 *	    | copy |
-		 *	    v	   v
-		 * RX SGL: AAD || PT || Tag
-		 */
-		memcpy_sglist(areq->first_rsgl.sgl.sgt.sgl, tsgl_src,
-			      processed);
-		af_alg_pull_tsgl(sk, processed, NULL, 0);
-	} else {
-		/*
-		 * Decryption operation - To achieve an in-place cipher
-		 * operation, the following  SGL structure is used:
-		 *
-		 * TX SGL: AAD || CT || Tag
-		 *	    |	   |	 ^
-		 *	    | copy |	 | Create SGL link.
-		 *	    v	   v	 |
-		 * RX SGL: AAD || CT ----+
-		 */
-
-		/* Copy AAD || CT to RX SGL buffer for in-place operation. */
-		memcpy_sglist(areq->first_rsgl.sgl.sgt.sgl, tsgl_src, outlen);
-
-		/* Create TX SGL for tag and chain it to RX SGL. */
-		areq->tsgl_entries = af_alg_count_tsgl(sk, processed,
-						       processed - as);
-		if (!areq->tsgl_entries)
-			areq->tsgl_entries = 1;
-		areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
-							 areq->tsgl_entries),
-					  GFP_KERNEL);
-		if (!areq->tsgl) {
-			err = -ENOMEM;
-			goto free;
-		}
-		sg_init_table(areq->tsgl, areq->tsgl_entries);
-
-		/* Release TX SGL, except for tag data and reassign tag data. */
-		af_alg_pull_tsgl(sk, processed, areq->tsgl, processed - as);
-
-		/* chain the areq TX SGL holding the tag with RX SGL */
-		if (usedpages) {
-			/* RX SGL present */
-			struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
-			struct scatterlist *sg = sgl_prev->sgt.sgl;
-
-			sg_unmark_end(sg + sgl_prev->sgt.nents - 1);
-			sg_chain(sg, sgl_prev->sgt.nents + 1, areq->tsgl);
-		} else
-			/* no RX SGL present (e.g. authentication only) */
-			rsgl_src = areq->tsgl;
-	}
+	memcpy_sglist(rsgl_src, tsgl_src, ctx->aead_assoclen);
 
 	/* Initialize the crypto operation */
 	aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
@@ -242,7 +180,7 @@
 	}
 
 	/* Initialize the crypto operation */
-	aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
+	aead_request_set_crypt(&areq->cra_u.aead_req, tsgl_src,
 			       areq->first_rsgl.sgl.sgt.sgl, used, ctx->iv);
 	aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
 	aead_request_set_tfm(&areq->cra_u.aead_req, tfm);

================================================================================
*    CONTEXT DIFFERENCES - surrounding code differences between the patches    *
================================================================================

--- b/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -28,5 +28,4 @@
 #include <crypto/if_alg.h>
 #include <crypto/skcipher.h>
-#include <crypto/null.h>
 #include <linux/init.h>
 #include <linux/list.h>
@@ -69,6 +69,6 @@
-	struct aead_tfm *aeadc = pask->private;
-	struct crypto_aead *tfm = aeadc->aead;
-	struct crypto_sync_skcipher *null_tfm = aeadc->null_tfm;
+	struct alg_sock *pask = alg_sk(psk);
+	struct af_alg_ctx *ctx = ask->private;
+	struct crypto_aead *tfm = pask->private;
 	unsigned int i, as = crypto_aead_authsize(tfm);
 	struct af_alg_async_req *areq;
 	struct af_alg_tsgl *tsgl, *tmp;
@@ -210,7 +184,7 @@
 	 */
 
 	/* Use the RX SGL as source (and destination) for crypto op. */
-	rsgl_src = areq->first_rsgl.sgl.sg;
+	rsgl_src = areq->first_rsgl.sgl.sgt.sgl;
 
 	if (ctx->enc) {
 		/*
@@ -223,10 +197,8 @@
 		 *	    v	   v
 		 * RX SGL: AAD || PT || Tag
 		 */
-		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
-					   areq->first_rsgl.sgl.sg, processed);
-		if (err)
-			goto free;
+		memcpy_sglist(areq->first_rsgl.sgl.sgt.sgl, tsgl_src,
+			      processed);
 		af_alg_pull_tsgl(sk, processed, NULL, 0);
 	} else {
 		/*
@@ -240,11 +212,8 @@
 		 * RX SGL: AAD || CT ----+
 		 */
 
-		 /* Copy AAD || CT to RX SGL buffer for in-place operation. */
-		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
-					   areq->first_rsgl.sgl.sg, outlen);
-		if (err)
-			goto free;
+		/* Copy AAD || CT to RX SGL buffer for in-place operation. */
+		memcpy_sglist(areq->first_rsgl.sgl.sgt.sgl, tsgl_src, outlen);
 
 		/* Create TX SGL for tag and chain it to RX SGL. */
 		areq->tsgl_entries = af_alg_count_tsgl(sk, processed,
@@ -267,10 +236,10 @@
 		if (usedpages) {
 			/* RX SGL present */
 			struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
+			struct scatterlist *sg = sgl_prev->sgt.sgl;
 
-			sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
-			sg_chain(sgl_prev->sg, sgl_prev->npages + 1,
-				 areq->tsgl);
+			sg_unmark_end(sg + sgl_prev->sgt.nents - 1);
+			sg_chain(sg, sgl_prev->sgt.nents + 1, areq->tsgl);
 		} else
 			/* no RX SGL present (e.g. authentication only) */
 			rsgl_src = areq->tsgl;
@@ -279,5 +248,5 @@
 	/* Initialize the crypto operation */
 	aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
-			       areq->first_rsgl.sgl.sg, used, ctx->iv);
+			       areq->first_rsgl.sgl.sgt.sgl, used, ctx->iv);
 	aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
 	aead_request_set_tfm(&areq->cra_u.aead_req, tfm);
@@ -478,4 +447,4 @@
-	struct crypto_aead *tfm = aeadc->aead;
+	struct crypto_aead *tfm = pask->private;
 	unsigned int ivlen = crypto_aead_ivsize(tfm);
 
 	af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
--- b/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -310,7 +359,7 @@
 	struct alg_sock *pask = alg_sk(psk);
 	struct crypto_skcipher *tfm = pask->private;
 
 	af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
 	sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm));
-	sock_kfree_s(sk, ctx, ctx->len);
-	af_alg_release_parent(sk);
+	if (ctx->state)
+		sock_kzfree_s(sk, ctx->state, crypto_skcipher_statesize(tfm));

This is an automated interdiff check for backported commits.

[github-actions]

✅ Validation checks completed successfully View full results: https://github.com/ctrliq/kernel-src-tree/actions/runs/25160821506

[roxanan1996]

obsolete