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FAILED: patch "[PATCH] crypto: do not free algorithm before using" failed to apply to 4.14-stable tree

PATCH [email protected] 1 participant 1 message Dec 11, 2018

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The patch below does not apply to the 4.14-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 <[email protected]>.

thanks,

greg k-h

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

Quoted 1 line

From e5bde04ccce64d808f8b00a489a1fe5825d285cb Mon Sep 17 00:00:00 2001

From: Pan Bian <[email protected]>
Date: Thu, 22 Nov 2018 18:00:16 +0800
Subject: [PATCH] crypto: do not free algorithm before using

In multiple functions, the algorithm fields are read after its reference is dropped through crypto_mod_put. In this case, the algorithm memory may be freed, resulting in use-after-free bugs. This patch delays the put operation until the algorithm is never used.

Fixes 79c65d179a40 ("crypto: cbc - Convert to skcipher")
Fixes a7d85e06ed80 ("crypto: cfb - add support for Cipher FeedBack mode")
Fixes 043a44001b9e ("crypto: pcbc - Convert to skcipher")
Cc <[email protected]>
Signed-off-by Pan Bian <[email protected]>
Signed-off-by Herbert Xu <[email protected]>
crypto/cbc.c +4 -2
index b761b1f9c6ca..dd5f332fd566 100644
@@ -140,9 +140,8 @@ static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
 	spawn = skcipher_instance_ctx(inst);
 	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
 				CRYPTO_ALG_TYPE_MASK);
-	crypto_mod_put(alg);
 	if (err)
-		goto err_free_inst;
+		goto err_put_alg;
 
 	err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg);
 	if (err)

@@ -174,12 +173,15 @@ static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
 	err = skcipher_register_instance(tmpl, inst);
 	if (err)
 		goto err_drop_spawn;
+	crypto_mod_put(alg);
 
 out:
 	return err;
 
 err_drop_spawn:
 	crypto_drop_spawn(spawn);
+err_put_alg:
+	crypto_mod_put(alg);
 err_free_inst:
 	kfree(inst);
 	goto out;
crypto/cfb.c +4 -2
index a0d68c09e1b9..20987d0e09d8 100644
@@ -286,9 +286,8 @@ static int crypto_cfb_create(struct crypto_template *tmpl, struct rtattr **tb)
 	spawn = skcipher_instance_ctx(inst);
 	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
 				CRYPTO_ALG_TYPE_MASK);
-	crypto_mod_put(alg);
 	if (err)
-		goto err_free_inst;
+		goto err_put_alg;
 
 	err = crypto_inst_setname(skcipher_crypto_instance(inst), "cfb", alg);
 	if (err)

@@ -317,12 +316,15 @@ static int crypto_cfb_create(struct crypto_template *tmpl, struct rtattr **tb)
 	err = skcipher_register_instance(tmpl, inst);
 	if (err)
 		goto err_drop_spawn;
+	crypto_mod_put(alg);
 
 out:
 	return err;
 
 err_drop_spawn:
 	crypto_drop_spawn(spawn);
+err_put_alg:
+	crypto_mod_put(alg);
 err_free_inst:
 	kfree(inst);
 	goto out;
crypto/pcbc.c +4 -2
index ef802f6e9642..8aa10144407c 100644
@@ -244,9 +244,8 @@ static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
 	spawn = skcipher_instance_ctx(inst);
 	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
 				CRYPTO_ALG_TYPE_MASK);
-	crypto_mod_put(alg);
 	if (err)
-		goto err_free_inst;
+		goto err_put_alg;
 
 	err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
 	if (err)

@@ -275,12 +274,15 @@ static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
 	err = skcipher_register_instance(tmpl, inst);
 	if (err)
 		goto err_drop_spawn;
+	crypto_mod_put(alg);
 
 out:
 	return err;
 
 err_drop_spawn:
 	crypto_drop_spawn(spawn);
+err_put_alg:
+	crypto_mod_put(alg);
 err_free_inst:
 	kfree(inst);
 	goto out;