The buffer 'derived_buf' in the function get_derived_key() must be
allocated dynamically in order to make room for an arbitrary length
master key.

Signed-off-by: Roberto Sassu <roberto.sa...@polito.it>
---
 security/keys/encrypted_defined.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/security/keys/encrypted_defined.c 
b/security/keys/encrypted_defined.c
index 5331925..65d9b13 100644
--- a/security/keys/encrypted_defined.c
+++ b/security/keys/encrypted_defined.c
@@ -289,10 +289,20 @@ enum derived_key_type { ENC_KEY, AUTH_KEY };
 static int get_derived_key(char *derived_key, enum derived_key_type key_type,
                           void *master_key, unsigned int master_keylen)
 {
-       char derived_buf[hash_size + 10];
+       char *derived_buf;
        int ret;
+       unsigned int derived_buf_len;
+
+       derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen;
+       if (derived_buf_len < hash_size)
+               derived_buf_len = hash_size;
+
+       derived_buf = kzalloc(derived_buf_len, GFP_KERNEL);
+       if (!derived_buf) {
+               pr_err("encrypted_key: out of memory\n");
+               return -ENOMEM;
+       }
 
-       memset(derived_buf, 0, sizeof derived_buf);
        if (key_type)
                strcpy(derived_buf, "AUTH_KEY");
        else
@@ -301,6 +311,7 @@ static int get_derived_key(char *derived_key, enum 
derived_key_type key_type,
        memcpy(derived_buf + strlen(derived_buf) + 1, master_key,
               master_keylen);
        ret = calc_hash(derived_key, derived_buf, sizeof derived_buf);
+       kfree(derived_buf);
        return ret;
 }
 
-- 
1.7.2.3

Attachment: smime.p7s
Description: S/MIME cryptographic signature

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