From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- net/atm/raw.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 net/atm/raw.c (limited to 'net/atm/raw.c') diff --git a/net/atm/raw.c b/net/atm/raw.c new file mode 100644 index 000000000..87d136c75 --- /dev/null +++ b/net/atm/raw.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +/* net/atm/raw.c - Raw AAL0 and AAL5 transports */ + +/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */ + +#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__ + +#include +#include +#include +#include +#include +#include +#include + +#include "common.h" +#include "protocols.h" + +/* + * SKB == NULL indicates that the link is being closed + */ + +static void atm_push_raw(struct atm_vcc *vcc, struct sk_buff *skb) +{ + if (skb) { + struct sock *sk = sk_atm(vcc); + + skb_queue_tail(&sk->sk_receive_queue, skb); + sk->sk_data_ready(sk); + } +} + +static void atm_pop_raw(struct atm_vcc *vcc, struct sk_buff *skb) +{ + struct sock *sk = sk_atm(vcc); + + pr_debug("(%d) %d -= %d\n", + vcc->vci, sk_wmem_alloc_get(sk), ATM_SKB(skb)->acct_truesize); + atm_return_tx(vcc, skb); + dev_kfree_skb_any(skb); + sk->sk_write_space(sk); +} + +static int atm_send_aal0(struct atm_vcc *vcc, struct sk_buff *skb) +{ + /* + * Note that if vpi/vci are _ANY or _UNSPEC the below will + * still work + */ + if (!capable(CAP_NET_ADMIN) && + (((u32 *)skb->data)[0] & (ATM_HDR_VPI_MASK | ATM_HDR_VCI_MASK)) != + ((vcc->vpi << ATM_HDR_VPI_SHIFT) | + (vcc->vci << ATM_HDR_VCI_SHIFT))) { + kfree_skb(skb); + return -EADDRNOTAVAIL; + } + return vcc->dev->ops->send(vcc, skb); +} + +int atm_init_aal0(struct atm_vcc *vcc) +{ + vcc->push = atm_push_raw; + vcc->pop = atm_pop_raw; + vcc->send = atm_send_aal0; + return 0; +} + +int atm_init_aal5(struct atm_vcc *vcc) +{ + vcc->push = atm_push_raw; + vcc->pop = atm_pop_raw; + vcc->send = vcc->dev->ops->send; + return 0; +} +EXPORT_SYMBOL(atm_init_aal5); -- cgit v1.3.1