Instead of determining and allocating a char array for use during usage of
crypto_shash_* calls, would like to instead dynamically
allocate (and free) storage for the duration of crypto calculation
(crypto_shash_init,
crypto_shash_update, and crypto_shash_final)
But everytime I try, it results in some sort of oops in the cifs module.
The motivation is to avoid sparse warnings like this
CHECK fs/cifs/cifsencrypt.c
fs/cifs/cifsencrypt.c:51:33: error: bad constant expression
fs/cifs/cifsencrypt.c:121:33: error: bad constant expression
fs/cifs/cifsencrypt.c:318:33: error: bad constant expression
fs/cifs/cifsencrypt.c:447:33: error: bad constant expression
fs/cifs/cifsencrypt.c:485:33: error: bad constant expression
that are generated because the size is ctx array is undetermined at
compile time.
+struct sdesc {
+ struct shash_desc shash;
+ char *ctx;
+};
@@ -46,21 +46,25 @@ static int cifs_calculate_signature(const struct
smb_hdr *cifs_pdu,
struct TCP_Server_Info *server, char *signature)
{
int rc = 0;
- struct {
- struct shash_desc shash;
- char ctx[crypto_shash_descsize(server->ntlmssp.md5)];
- } sdesc;
+ struct sdesc sdesc;
if (cifs_pdu == NULL || server == NULL || signature == NULL)
return -EINVAL;
+ sdesc.ctx = kmalloc(crypto_shash_descsize(server->ntlmssp.md5),
+ GFP_KERNEL);
+ if (!sdesc.ctx) {
+ cERROR(1, "cifs_calculate_signature: could not
initialize crypto hmacmd5\n");
+ return -ENOMEM;
+ }
+
sdesc.shash.tfm = server->ntlmssp.md5;
sdesc.shash.flags = 0x0;
rc = crypto_shash_init(&sdesc.shash);
if (rc) {
cERROR(1, "could not initialize master crypto API hmacmd5\n");
- return rc;
+ goto calc_sig_ret;
}
--
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