Re: PING: [PATCH] crypto: public_key: fix overflow during implicit conversion

On Wed, 2021-08-18 at 16:33 +0800, zhenwei pi wrote:

PING

Please, do not top-post.

You are lacking Herbert Xu:

$ scripts/get_maintainer.pl crypto/asymmetric_keys/public_key.c 
David Howells [off-list ref] (maintainer:ASYMMETRIC KEYS)
Herbert Xu [off-list ref] (maintainer:CRYPTO API)
"David S. Miller" [off-list ref] (maintainer:CRYPTO API)
keyrings@vger.kernel.org (open list:ASYMMETRIC KEYS)
linux-crypto@vger.kernel.org (open list:CRYPTO API)
linux-kernel@vger.kernel.org (open list)

On 8/10/21 2:39 PM, zhenwei pi wrote:

quoted

Hit kernel warning like this, it can be reproduced by verifying 256
bytes datafile by keyctl command.

  WARNING: CPU: 5 PID: 344556 at crypto/rsa-pkcs1pad.c:540
pkcs1pad_verify+0x160/0x190
  ...
  Call Trace:
   public_key_verify_signature+0x282/0x380
   ? software_key_query+0x12d/0x180
   ? keyctl_pkey_params_get+0xd6/0x130
   asymmetric_key_verify_signature+0x66/0x80
   keyctl_pkey_verify+0xa5/0x100
   do_syscall_64+0x35/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xae

'.digest_size(u8) = params->in_len(u32)' leads overflow of an u8

Where is this statement?

quoted

value,
so use u32 instead of u8 of digest. And reorder struct
public_key_signature, it could save 8 bytes on a 64 bit machine.

                                                     ~~~~~
                                                     64-bit
                                                     
What do you mean by "could"? Does it, or does it
not?                                                                   
                                       					
	  								
									
		

quoted

Signed-off-by: zhenwei pi <redacted>

Nit: "Firstname Lastname" (first letters capitalized)

quoted

---
  include/crypto/public_key.h | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/crypto/public_key.h

b/include/crypto/public_key.h
index 47accec68cb0..f603325c0c30 100644

--- a/include/crypto/public_key.h
+++ b/include/crypto/public_key.h

@@ -38,9 +38,9 @@ extern void public_key_free(struct public_key

*key);
  struct public_key_signature {
  	struct asymmetric_key_id *auth_ids[2];
  	u8 *s;			/* Signature */
-	u32 s_size;		/* Number of bytes in signature */
  	u8 *digest;
-	u8 digest_size;		/* Number of bytes in digest */
+	u32 s_size;		/* Number of bytes in signature */
+	u32 digest_size;	/* Number of bytes in digest */
  	const char *pkey_algo;
  	const char *hash_algo;
  	const char *encoding;

/Jarkko