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libceph: harden msgr2.1 frame segment length checks

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commit a282a2f105 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: cd1a677cad ("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>
This commit is contained in:
Ilya Dryomov 2023-07-10 20:39:29 +02:00 committed by Greg Kroah-Hartman
parent cb8a31a56d
commit 183c0ae4fa
1 changed files with 29 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

47
net/ceph/messenger_v2.c
View file

@ -392,6 +392,8 @@ static int head_onwire_len(int ctrl_len, bool secure)
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, bool secure)
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, struct ceph_frame_desc *desc)
desc->fd_aligns[i] = ceph_decode_16(&p);
}
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[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[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[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;
}
/*
* 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");
return -EINVAL;
}
if (desc->fd_lens[0] > CEPH_MSG_MAX_CONTROL_LEN) {
pr_err("control segment too big %d\n", desc->fd_lens[0]);
return -EINVAL;
}
if (desc->fd_lens[1] > CEPH_MSG_MAX_FRONT_LEN) {
pr_err("front segment too big %d\n", desc->fd_lens[1]);
return -EINVAL;
}
if (desc->fd_lens[2] > CEPH_MSG_MAX_MIDDLE_LEN) {
pr_err("middle segment too big %d\n", desc->fd_lens[2]);
return -EINVAL;
}
if (desc->fd_lens[3] > CEPH_MSG_MAX_DATA_LEN) {
pr_err("data segment too big %d\n", desc->fd_lens[3]);
pr_err("last segment empty, segment count %d\n",
desc->fd_seg_cnt);
return -EINVAL;
}