commit d68894800ec5712d7ddf042356f11e36f87d7f78 upstream.
In nfs_idmap_read_and_verify_message there is an incorrect sprintf '%d'
that converts the __u32 'im_id' from struct idmap_msg to 'id_str', which
is a stack char array variable of length NFS_UINT_MAXLEN == 11.
If a uid or gid value is > 2147483647 = 0x7fffffff, the conversion
overflows into a negative value, for example:
crash> p (unsigned) (0x80000000)
$1 = 2147483648
crash> p (signed) (0x80000000)
$2 = -2147483648
The '-' sign is written to the buffer and this causes a 1 byte overflow
when the NULL byte is written, which corrupts kernel stack memory. If
CONFIG_CC_STACKPROTECTOR_STRONG is set we see a stack-protector panic:
[11558053.616565] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffffa05b8a8c
[11558053.639063] CPU: 6 PID: 9423 Comm: rpc.idmapd Tainted: G W ------------ T 3.10.0-514.el7.x86_64 #1
[11558053.641990] Hardware name: Red Hat OpenStack Compute, BIOS 1.10.2-3.el7_4.1 04/01/2014
[11558053.644462] ffffffff818c7bc0 00000000b1f3aec1 ffff880de0f9bd48 ffffffff81685eac
[11558053.646430] ffff880de0f9bdc8 ffffffff8167f2b3 ffffffff00000010 ffff880de0f9bdd8
[11558053.648313] ffff880de0f9bd78 00000000b1f3aec1 ffffffff811dcb03 ffffffffa05b8a8c
[11558053.650107] Call Trace:
[11558053.651347] [<ffffffff81685eac>] dump_stack+0x19/0x1b
[11558053.653013] [<ffffffff8167f2b3>] panic+0xe3/0x1f2
[11558053.666240] [<ffffffff811dcb03>] ? kfree+0x103/0x140
[11558053.682589] [<ffffffffa05b8a8c>] ? idmap_pipe_downcall+0x1cc/0x1e0 [nfsv4]
[11558053.689710] [<ffffffff810855db>] __stack_chk_fail+0x1b/0x30
[11558053.691619] [<ffffffffa05b8a8c>] idmap_pipe_downcall+0x1cc/0x1e0 [nfsv4]
[11558053.693867] [<ffffffffa00209d6>] rpc_pipe_write+0x56/0x70 [sunrpc]
[11558053.695763] [<ffffffff811fe12d>] vfs_write+0xbd/0x1e0
[11558053.702236] [<ffffffff810acccc>] ? task_work_run+0xac/0xe0
[11558053.704215] [<ffffffff811fec4f>] SyS_write+0x7f/0xe0
[11558053.709674] [<ffffffff816964c9>] system_call_fastpath+0x16/0x1b
Fix this by calling the internally defined nfs_map_numeric_to_string()
function which properly uses '%u' to convert this __u32. For consistency,
also replace the one other place where snprintf is called.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Reported-by: Stephen Johnston <sjohnsto@redhat.com>
Fixes: cf4ab538f1 ("NFSv4: Fix the string length returned by the idmapper")
Cc: stable@vger.kernel.org # v3.4+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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: 57e62324e4 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The idmap_init() and idmap_quit() functions only exist to call the
_keyring() version. Let's just call the keyring() functions directly.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Delete jump to a label on the next line, when that label is not
used elsewhere.
A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@r@
identifier l;
@@
-if (...) goto l;
-l:
// </smpl>
Also drop the unnecessary ret variable.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
I added the nfs4 prefix to make it obvious that this file is built into
the NFS v4 module, and not the generic client.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
