From: Ilya Dryomov idryomov@gmail.com
commit a282a2f10539dce2aa619e71e1817570d557fc97 upstream.
ceph_frame_desc::fd_lens is an int array. decode_preamble() thus effectively casts u32 -> int but the checks for segment lengths are written as if on unsigned values. While reading in HELLO or one of the AUTH frames (before authentication is completed), arithmetic in head_onwire_len() can get duped by negative ctrl_len and produce head_len which is less than CEPH_PREAMBLE_LEN but still positive. This would lead to a buffer overrun in prepare_read_control() as the preamble gets copied to the newly allocated buffer of size head_len.
Cc: stable@vger.kernel.org Fixes: cd1a677cad99 ("libceph, ceph: implement msgr2.1 protocol (crc and secure modes)") Reported-by: Thelford Williams thelford@google.com Signed-off-by: Ilya Dryomov idryomov@gmail.com Reviewed-by: Xiubo Li xiubli@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ceph/messenger_v2.c | 41 ++++++++++++++++++++++++++--------------- 1 file changed, 26 insertions(+), 15 deletions(-)
--- a/net/ceph/messenger_v2.c +++ b/net/ceph/messenger_v2.c @@ -392,6 +392,8 @@ static int head_onwire_len(int ctrl_len, int head_len; int rem_len;
+ BUG_ON(ctrl_len < 0 || ctrl_len > CEPH_MSG_MAX_CONTROL_LEN); + if (secure) { head_len = CEPH_PREAMBLE_SECURE_LEN; if (ctrl_len > CEPH_PREAMBLE_INLINE_LEN) { @@ -410,6 +412,10 @@ static int head_onwire_len(int ctrl_len, static int __tail_onwire_len(int front_len, int middle_len, int data_len, bool secure) { + BUG_ON(front_len < 0 || front_len > CEPH_MSG_MAX_FRONT_LEN || + middle_len < 0 || middle_len > CEPH_MSG_MAX_MIDDLE_LEN || + data_len < 0 || data_len > CEPH_MSG_MAX_DATA_LEN); + if (!front_len && !middle_len && !data_len) return 0;
@@ -522,29 +528,34 @@ static int decode_preamble(void *p, stru desc->fd_aligns[i] = ceph_decode_16(&p); }
- /* - * This would fire for FRAME_TAG_WAIT (it has one empty - * segment), but we should never get it as client. - */ - if (!desc->fd_lens[desc->fd_seg_cnt - 1]) { - pr_err("last segment empty\n"); + if (desc->fd_lens[0] < 0 || + desc->fd_lens[0] > CEPH_MSG_MAX_CONTROL_LEN) { + pr_err("bad control segment length %d\n", desc->fd_lens[0]); return -EINVAL; } - - if (desc->fd_lens[0] > CEPH_MSG_MAX_CONTROL_LEN) { - pr_err("control segment too big %d\n", desc->fd_lens[0]); + if (desc->fd_lens[1] < 0 || + desc->fd_lens[1] > CEPH_MSG_MAX_FRONT_LEN) { + pr_err("bad front segment length %d\n", desc->fd_lens[1]); return -EINVAL; } - if (desc->fd_lens[1] > CEPH_MSG_MAX_FRONT_LEN) { - pr_err("front segment too big %d\n", desc->fd_lens[1]); + if (desc->fd_lens[2] < 0 || + desc->fd_lens[2] > CEPH_MSG_MAX_MIDDLE_LEN) { + pr_err("bad middle segment length %d\n", desc->fd_lens[2]); return -EINVAL; } - if (desc->fd_lens[2] > CEPH_MSG_MAX_MIDDLE_LEN) { - pr_err("middle segment too big %d\n", desc->fd_lens[2]); + if (desc->fd_lens[3] < 0 || + desc->fd_lens[3] > CEPH_MSG_MAX_DATA_LEN) { + pr_err("bad data segment length %d\n", desc->fd_lens[3]); return -EINVAL; } - if (desc->fd_lens[3] > CEPH_MSG_MAX_DATA_LEN) { - pr_err("data segment too big %d\n", desc->fd_lens[3]); + + /* + * This would fire for FRAME_TAG_WAIT (it has one empty + * segment), but we should never get it as client. + */ + if (!desc->fd_lens[desc->fd_seg_cnt - 1]) { + pr_err("last segment empty, segment count %d\n", + desc->fd_seg_cnt); return -EINVAL; }