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| author | Eric Biggers <ebiggers@google.com> | 2017-06-08 14:48:18 +0100 |
|---|---|---|
| committer | Shirle Yuen <shirleyshukyee@google.com> | 2018-08-05 16:45:54 -0700 |
| commit | 41e340b4bdcb65ff9f1eb949138dffdea82f9b7f (patch) | |
| tree | bdf000be4655c46ce554c830c1629d0634e7e93d | |
| parent | 336d88c2047cd6bbaa24900427c6b1aaf4f030f6 (diff) | |
| download | qcom-msm8x09-v3.10-41e340b4bdcb65ff9f1eb949138dffdea82f9b7f.tar.gz | |
KEYS: encrypted: fix buffer overread in valid_master_desc()
With the 'encrypted' key type it was possible for userspace to provide a
data blob ending with a master key description shorter than expected,
e.g. 'keyctl add encrypted desc "new x" @s'. When validating such a
master key description, validate_master_desc() could read beyond the end
of the buffer. Fix this by using strncmp() instead of memcmp(). [Also
clean up the code to deduplicate some logic.]
Bug: 111289931
Change-Id: Ib88f30f89c1854a1650ea2b58c2871a515297d82
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Git-commit: 794b4bc292f5d31739d89c0202c54e7dc9bc3add
Git-repo: https://android.googlesource.com/kernel/common
Signed-off-by: Srinivasa Rao Kuppala <srkupp@codeaurora.org>
(cherry picked from commit d3be9b4799a57e880d1378f6906fe7d4a653e11b)
| -rw-r--r-- | security/keys/encrypted-keys/encrypted.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 9e1e005c759..fabb763bba1 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -141,23 +141,22 @@ static int valid_ecryptfs_desc(const char *ecryptfs_desc) */ static int valid_master_desc(const char *new_desc, const char *orig_desc) { - if (!memcmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) { - if (strlen(new_desc) == KEY_TRUSTED_PREFIX_LEN) - goto out; - if (orig_desc) - if (memcmp(new_desc, orig_desc, KEY_TRUSTED_PREFIX_LEN)) - goto out; - } else if (!memcmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) { - if (strlen(new_desc) == KEY_USER_PREFIX_LEN) - goto out; - if (orig_desc) - if (memcmp(new_desc, orig_desc, KEY_USER_PREFIX_LEN)) - goto out; - } else - goto out; + int prefix_len; + + if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) + prefix_len = KEY_TRUSTED_PREFIX_LEN; + else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) + prefix_len = KEY_USER_PREFIX_LEN; + else + return -EINVAL; + + if (!new_desc[prefix_len]) + return -EINVAL; + + if (orig_desc && strncmp(new_desc, orig_desc, prefix_len)) + return -EINVAL; + return 0; -out: - return -EINVAL; } /* |