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| author | Eric Biggers <ebiggers@google.com> | 2018-01-20 02:15:34 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-06-17 00:21:58 +0300 |
| commit | bd39ed5096a41942cbb319a763231bc695b0b24e (patch) | |
| tree | aac0bcd5d574b2c878b87bcb69d05e1b425c5c55 | |
| parent | 13006b429b43e4620c72e0d152a808a2613f7d69 (diff) | |
| download | linux-bd39ed5096a41942cbb319a763231bc695b0b24e.tar.xz | |
NFS: reject request for id_legacy key without auxdata
commit 49686cbbb3ebafe42e63868222f269d8053ead00 upstream.
nfs_idmap_legacy_upcall() is supposed to be called with 'aux' pointing
to a 'struct idmap', via the call to request_key_with_auxdata() in
nfs_idmap_request_key().
However it can also be reached via the request_key() system call in
which case 'aux' will be NULL, causing a NULL pointer dereference in
nfs_idmap_prepare_pipe_upcall(), assuming that the key description is
valid enough to get that far.
Fix this by making nfs_idmap_legacy_upcall() negate the key if no
auxdata is provided.
As usual, this bug was found by syzkaller. A simple reproducer using
the command-line keyctl program is:
keyctl request2 id_legacy uid:0 '' @s
Fixes: 57e62324e469 ("NFS: Store the legacy idmapper result in the keyring")
Reported-by: syzbot+5dfdbcf7b3eb5912abbb@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Trond Myklebust <trondmy@gmail.com>
pbwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | fs/nfs/idmap.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c index 567983d2c0eb..11450097e4ed 100644 --- a/fs/nfs/idmap.c +++ b/fs/nfs/idmap.c @@ -577,9 +577,13 @@ static int nfs_idmap_legacy_upcall(struct key_construction *cons, struct idmap_msg *im; struct idmap *idmap = (struct idmap *)aux; struct key *key = cons->key; - int ret = -ENOMEM; + int ret = -ENOKEY; + + if (!aux) + goto out1; /* msg and im are freed in idmap_pipe_destroy_msg */ + ret = -ENOMEM; data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) goto out1; |