CVE-2021-3764: Missing Release of Memory after Effective Lifetime (CWE-401)
value: A memory leak flaw was found in the Linux kernel's ccp_run_aes_gcm_cmd() function that allows an attacker to cause a denial of service. The vulnerability is similar to the older CVE-2019-18808. The highest threat from this vulnerability is to system availability.
CWE description: The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.
CVSS v3 base score: 5.5
Published: 2022-08-23T16:15Z
Repository: https://github.com/torvalds/linux
Language: C
Files changed: drivers/crypto/ccp/ccp-ops.c
Commit date: 2021-09-24 15:58:41 +0800
Commit message: crypto: ccp - fix resource leaks in ccp_run_aes_gcm_cmd()

There are three bugs in this code:

1) If we ccp_init_data() fails for &src then we need to free aad.
   Use goto e_aad instead of goto e_ctx.
2) The label to free the &final_wa was named incorrectly as "e_tag" but
   it should have been "e_final_wa".  One error path leaked &final_wa.
3) The &tag was leaked on one error path.  In that case, I added a free
   before the goto because the resource was local to that block.

Fixes: 36cf515b9bbe ("crypto: ccp - Enable support for AES GCM on v5 CCPs")
Reported-by: "minihanshen(沈明航)" <minihanshen@tencent.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: John Allen <john.allen@amd.com>
Tested-by: John Allen <john.allen@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Diff: diff --git a/drivers/crypto/ccp/ccp-ops.c b/drivers/crypto/ccp/ccp-ops.c
index bb88198c874e..aa4e1a500691 100644
--- a/drivers/crypto/ccp/ccp-ops.c
+++ b/drivers/crypto/ccp/ccp-ops.c
@@ -776,11 +776,11 @@ ccp_run_aes_gcm_cmd(struct ccp_cmd_queue *cmd_q, struct ccp_cmd *cmd)
 		ret = ccp_init_data(&src, cmd_q, p_inp, ilen,
 				    AES_BLOCK_SIZE,
 				    in_place ? DMA_BIDIRECTIONAL
 					     : DMA_TO_DEVICE);
 		if (ret)
-			goto e_ctx;
+			goto e_aad;
 
 		if (in_place) {
 			dst = src;
 		} else {
 			ret = ccp_init_data(&dst, cmd_q, p_outp, ilen,
@@ -861,31 +861,33 @@ ccp_run_aes_gcm_cmd(struct ccp_cmd_queue *cmd_q, struct ccp_cmd *cmd)
 	op.dst.u.dma.length = AES_BLOCK_SIZE;
 	op.eom = 1;
 	op.u.aes.size = 0;
 	ret = cmd_q->ccp->vdata->perform->aes(&op);
 	if (ret)
-		goto e_dst;
+		goto e_final_wa;
 
 	if (aes->action == CCP_AES_ACTION_ENCRYPT) {
 		/* Put the ciphered tag after the ciphertext. */
 		ccp_get_dm_area(&final_wa, 0, p_tag, 0, authsize);
 	} else {
 		/* Does this ciphered tag match the input? */
 		ret = ccp_init_dm_workarea(&tag, cmd_q, authsize,
 					   DMA_BIDIRECTIONAL);
 		if (ret)
-			goto e_tag;
+			goto e_final_wa;
 		ret = ccp_set_dm_area(&tag, 0, p_tag, 0, authsize);
-		if (ret)
-			goto e_tag;
+		if (ret) {
+			ccp_dm_free(&tag);
+			goto e_final_wa;
+		}
 
 		ret = crypto_memneq(tag.address, final_wa.address,
 				    authsize) ? -EBADMSG : 0;
 		ccp_dm_free(&tag);
 	}
 
-e_tag:
+e_final_wa:
 	ccp_dm_free(&final_wa);
 
 e_dst:
 	if (ilen > 0 && !in_place)
 		ccp_free_data(&dst, cmd_q);

Vulnerable code: 			goto e_ctx;
		goto e_dst;
			goto e_tag;
		if (ret)
			goto e_tag;
e_tag:
Fixed code: 			goto e_aad;
		goto e_final_wa;
			goto e_final_wa;
		if (ret) {
			ccp_dm_free(&tag);
			goto e_final_wa;
		}
e_final_wa: