[PATCH 0/4] crypto: caam - fix use-after-free KASAN issue

[PATCH 0/4] crypto: caam - fix use-after-free KASAN issue

[Iuliana Prodan]

This series fixes a use-after-free KASAN issue that was introduce by CAAM backlogging support[1].
This is fixed for SKCIPHER, HASH, RSA and AEAD algorithms.

[1] https://patchwork.kernel.org/cover/11378941/

Iuliana Prodan (4):
  crypto: caam - fix use-after-free KASAN issue for SKCIPHER algorithms
  crypto: caam - fix use-after-free KASAN issue for AEAD algorithms
  crypto: caam - fix use-after-free KASAN issue for HASH algorithms
  crypto: caam - fix use-after-free KASAN issue for RSA algorithms

 drivers/crypto/caam/caamalg.c  | 8 ++++----
 drivers/crypto/caam/caamhash.c | 5 +++--
 drivers/crypto/caam/caampkc.c  | 6 ++++--
 3 files changed, 11 insertions(+), 8 deletions(-)

-- 
2.1.0

[PATCH 1/4] crypto: caam - fix use-after-free KASAN issue for SKCIPHER algorithms

[Iuliana Prodan]

Here's the KASAN report:
BUG: KASAN: use-after-free in skcipher_crypt_done+0xe8/0x1a8
Read of size 1 at addr ffff00002304001c by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc1-00162-gfcb90d5 #9
Hardware name: LS1046A RDB Board (DT)
Call trace:
 dump_backtrace+0x0/0x260
 show_stack+0x14/0x20
 dump_stack+0xe8/0x144
 print_address_description.isra.11+0x64/0x348
 __kasan_report+0x11c/0x230
 kasan_report+0xc/0x18
 __asan_load1+0x5c/0x68
 skcipher_crypt_done+0xe8/0x1a8
 caam_jr_dequeue+0x390/0x608
 tasklet_action_common.isra.13+0x1ec/0x230
 ...

Fixes: ee38767f152a ("crypto: caam - support crypto_engine framework for SKCIPHER algorithms")
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
---
 drivers/crypto/caam/caamalg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index b7bb7c3..5538539 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -1022,8 +1022,6 @@ static void skcipher_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 		     DUMP_PREFIX_ADDRESS, 16, 4, req->dst,
 		     edesc->dst_nents > 1 ? 100 : req->cryptlen, 1);
 
-	kfree(edesc);
-
 	/*
 	 * If no backlog flag, the completion of the request is done
 	 * by CAAM, not crypto engine.
@@ -1032,6 +1030,8 @@ static void skcipher_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 		skcipher_request_complete(req, ecode);
 	else
 		crypto_finalize_skcipher_request(jrp->engine, req, ecode);
+
+	kfree(edesc);
 }
 
 /*
-- 
2.1.0

[PATCH 2/4] crypto: caam - fix use-after-free KASAN issue for AEAD algorithms

[Iuliana Prodan]

Here's the KASAN report:
BUG: KASAN: use-after-free in aead_crypt_done+0x60/0xd8
Read of size 1 at addr ffff00002303f014 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc1-00163-gd88dd5c-dirty #18
Hardware name: LS1046A RDB Board (DT)
Call trace:
 dump_backtrace+0x0/0x260
 show_stack+0x14/0x20
 dump_stack+0xe8/0x144
 print_address_description.isra.11+0x64/0x348
 __kasan_report+0x11c/0x230
 kasan_report+0xc/0x18
 __asan_load1+0x5c/0x68
 aead_crypt_done+0x60/0xd8
 caam_jr_dequeue+0x390/0x608
...

Fixes: 1c2402266713 ("crypto: caam - add crypto_engine support for AEAD algorithms")
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
---
 drivers/crypto/caam/caamalg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index 5538539..6d746ef 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -973,8 +973,6 @@ static void aead_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 
 	aead_unmap(jrdev, edesc, req);
 
-	kfree(edesc);
-
 	/*
 	 * If no backlog flag, the completion of the request is done
 	 * by CAAM, not crypto engine.
@@ -983,6 +981,8 @@ static void aead_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 		aead_request_complete(req, ecode);
 	else
 		crypto_finalize_aead_request(jrp->engine, req, ecode);
+
+	kfree(edesc);
 }
 
 static void skcipher_crypt_done(struct device *jrdev, u32 *desc, u32 err,
-- 
2.1.0

[PATCH 3/4] crypto: caam - fix use-after-free KASAN issue for HASH algorithms

[Iuliana Prodan]

Here's the KASAN report:
BUG: KASAN: use-after-free in ahash_done+0xdc/0x3b8
Read of size 1 at addr ffff000022e75510 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc1-00164-gcb59d59-dirty #20
Hardware name: LS1046A RDB Board (DT)
Call trace:
 dump_backtrace+0x0/0x260
 show_stack+0x14/0x20
 dump_stack+0xe8/0x144
 print_address_description.isra.11+0x64/0x348
 __kasan_report+0x11c/0x230
 kasan_report+0xc/0x18
 __asan_load1+0x5c/0x68
 ahash_done+0xdc/0x3b8
 caam_jr_dequeue+0x390/0x608
 tasklet_action_common.isra.13+0x1ec/0x230

Fixes: 21b014f038d3 ("crypto: caam - add crypto_engine support for HASH algorithms")
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
---
 drivers/crypto/caam/caamhash.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/caam/caamhash.c b/drivers/crypto/caam/caamhash.c
index 943bc02..3c63fe0 100644
--- a/drivers/crypto/caam/caamhash.c
+++ b/drivers/crypto/caam/caamhash.c
@@ -593,7 +593,6 @@ static inline void ahash_done_cpy(struct device *jrdev, u32 *desc, u32 err,
 
 	ahash_unmap_ctx(jrdev, edesc, req, digestsize, dir);
 	memcpy(req->result, state->caam_ctx, digestsize);
-	kfree(edesc);
 
 	print_hex_dump_debug("ctx@"__stringify(__LINE__)": ",
 			     DUMP_PREFIX_ADDRESS, 16, 4, state->caam_ctx,
@@ -607,6 +606,8 @@ static inline void ahash_done_cpy(struct device *jrdev, u32 *desc, u32 err,
 		req->base.complete(&req->base, ecode);
 	else
 		crypto_finalize_hash_request(jrp->engine, req, ecode);
+
+	kfree(edesc);
 }
 
 static void ahash_done(struct device *jrdev, u32 *desc, u32 err,
@@ -640,7 +641,6 @@ static inline void ahash_done_switch(struct device *jrdev, u32 *desc, u32 err,
 		ecode = caam_jr_strstatus(jrdev, err);
 
 	ahash_unmap_ctx(jrdev, edesc, req, ctx->ctx_len, dir);
-	kfree(edesc);
 
 	scatterwalk_map_and_copy(state->buf, req->src,
 				 req->nbytes - state->next_buflen,
@@ -668,6 +668,7 @@ static inline void ahash_done_switch(struct device *jrdev, u32 *desc, u32 err,
 	else
 		crypto_finalize_hash_request(jrp->engine, req, ecode);
 
+	kfree(edesc);
 }
 
 static void ahash_done_bi(struct device *jrdev, u32 *desc, u32 err,
-- 
2.1.0

[PATCH 4/4] crypto: caam - fix use-after-free KASAN issue for RSA algorithms

[Iuliana Prodan]

Here's the KASAN report:
BUG: KASAN: use-after-free in rsa_pub_done+0x70/0xe8
Read of size 1 at addr ffff00002267b614 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc1-00165-ga85dda9-dirty #21
Hardware name: LS1046A RDB Board (DT)
Call trace:
 dump_backtrace+0x0/0x260
 show_stack+0x14/0x20
 dump_stack+0xe8/0x144
 print_address_description.isra.11+0x64/0x348
 __kasan_report+0x11c/0x230
 kasan_report+0xc/0x18
 __asan_load1+0x5c/0x68
 rsa_pub_done+0x70/0xe8
 caam_jr_dequeue+0x390/0x608
 tasklet_action_common.isra.13+0x1ec/0x230
...

Fixes: bf53795025a2 ("crypto: caam - add crypto_engine support for RSA algorithms")
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
---
 drivers/crypto/caam/caampkc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/caam/caampkc.c b/drivers/crypto/caam/caampkc.c
index 4fcae37..59cc7116 100644
--- a/drivers/crypto/caam/caampkc.c
+++ b/drivers/crypto/caam/caampkc.c
@@ -129,7 +129,6 @@ static void rsa_pub_done(struct device *dev, u32 *desc, u32 err, void *context)
 
 	rsa_pub_unmap(dev, edesc, req);
 	rsa_io_unmap(dev, edesc, req);
-	kfree(edesc);
 
 	/*
 	 * If no backlog flag, the completion of the request is done
@@ -139,6 +138,8 @@ static void rsa_pub_done(struct device *dev, u32 *desc, u32 err, void *context)
 		akcipher_request_complete(req, ecode);
 	else
 		crypto_finalize_akcipher_request(jrp->engine, req, ecode);
+
+	kfree(edesc);
 }
 
 static void rsa_priv_f_done(struct device *dev, u32 *desc, u32 err,
@@ -170,7 +171,6 @@ static void rsa_priv_f_done(struct device *dev, u32 *desc, u32 err,
 	}
 
 	rsa_io_unmap(dev, edesc, req);
-	kfree(edesc);
 
 	/*
 	 * If no backlog flag, the completion of the request is done
@@ -180,6 +180,8 @@ static void rsa_priv_f_done(struct device *dev, u32 *desc, u32 err,
 		akcipher_request_complete(req, ecode);
 	else
 		crypto_finalize_akcipher_request(jrp->engine, req, ecode);
+
+	kfree(edesc);
 }
 
 /**
-- 
2.1.0

Re: [PATCH 2/4] crypto: caam - fix use-after-free KASAN issue for AEAD algorithms

[Horia Geantă]

On 4/5/2020 2:50 PM, Iuliana Prodan wrote:
> Here's the KASAN report:
> BUG: KASAN: use-after-free in aead_crypt_done+0x60/0xd8
> Read of size 1 at addr ffff00002303f014 by task swapper/0/0
> 
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc1-00163-gd88dd5c-dirty #18
This is no a public SHA1, you are probably running with patch 1/4
applied in the tree (and with a "dirty tree").

> Hardware name: LS1046A RDB Board (DT)
> Call trace:
>  dump_backtrace+0x0/0x260
>  show_stack+0x14/0x20
>  dump_stack+0xe8/0x144
>  print_address_description.isra.11+0x64/0x348
>  __kasan_report+0x11c/0x230
>  kasan_report+0xc/0x18
>  __asan_load1+0x5c/0x68
>  aead_crypt_done+0x60/0xd8
>  caam_jr_dequeue+0x390/0x608
> ...
You should provide full KASan log - shawdow bits etc.

> @@ -973,8 +973,6 @@ static void aead_crypt_done(struct device *jrdev, u32 *desc, u32 err,
>  
>  	aead_unmap(jrdev, edesc, req);
>  
> -	kfree(edesc);
> -
>  	/*
>  	 * If no backlog flag, the completion of the request is done
>  	 * by CAAM, not crypto engine.
> @@ -983,6 +981,8 @@ static void aead_crypt_done(struct device *jrdev, u32 *desc, u32 err,
>  		aead_request_complete(req, ecode);
>  	else
>  		crypto_finalize_aead_request(jrp->engine, req, ecode);
> +
> +	kfree(edesc);
I think it's better freeing all resources before calling
the completion callback, to avoid unnecessary memory strains.

Horia