diff options
| author | Jeff Layton <jlayton@redhat.com> | 2012-12-03 12:05:30 +0100 |
|---|---|---|
| committer | Steve French <smfrench@gmail.com> | 2012-12-09 05:04:32 +0100 |
| commit | 2ae03025d520de581fd1c58e98bbf3045c0f4695 (patch) | |
| tree | 4795149c42b5ecdddd4540dd97c0972522183ea5 /fs/cifs/cifsacl.c | |
| parent | cifs: avoid extra allocation for small cifs.idmap keys (diff) | |
| download | linux-2ae03025d520de581fd1c58e98bbf3045c0f4695.tar.xz linux-2ae03025d520de581fd1c58e98bbf3045c0f4695.zip | |
cifs: extra sanity checking for cifs.idmap keys
Now that we aren't so rigid about the length of the key being passed
in, we need to be a bit more rigorous about checking the length of
the actual data against the claimed length (a'la num_subauths field).
Check for the case where userspace sends us a seemingly valid key
with a num_subauths field that goes beyond the end of the array. If
that happens, return -EIO and invalidate the key.
Also change the other places where we check for malformed keys in this
code to invalidate the key as well.
Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/cifsacl.c')
| -rw-r--r-- | fs/cifs/cifsacl.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c index 751d34bd825c..b0b114acdece 100644 --- a/fs/cifs/cifsacl.c +++ b/fs/cifs/cifsacl.c @@ -191,6 +191,8 @@ id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid) { int rc; struct key *sidkey; + struct cifs_sid *ksid; + unsigned int ksid_size; char desc[3 + 10 + 1]; /* 3 byte prefix + 10 bytes for value + NULL */ const struct cred *saved_cred; @@ -211,14 +213,27 @@ id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid) rc = -EIO; cFYI(1, "%s: Downcall contained malformed key " "(datalen=%hu)", __func__, sidkey->datalen); - goto out_key_put; + goto invalidate_key; } - cifs_copy_sid(ssid, (struct cifs_sid *)sidkey->payload.data); + + ksid = (struct cifs_sid *)sidkey->payload.data; + ksid_size = CIFS_SID_BASE_SIZE + (ksid->num_subauth * sizeof(__le32)); + if (ksid_size > sidkey->datalen) { + rc = -EIO; + cFYI(1, "%s: Downcall contained malformed key (datalen=%hu, " + "ksid_size=%u)", __func__, sidkey->datalen, ksid_size); + goto invalidate_key; + } + cifs_copy_sid(ssid, ksid); out_key_put: key_put(sidkey); out_revert_creds: revert_creds(saved_cred); return rc; + +invalidate_key: + key_invalidate(sidkey); + goto out_key_put; } static int @@ -264,6 +279,7 @@ sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid, rc = -EIO; cFYI(1, "%s: Downcall contained malformed key " "(datalen=%hu)", __func__, sidkey->datalen); + key_invalidate(sidkey); goto out_key_put; } |