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/dns_resolver/internal.h | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 net/dns_resolver/internal.h (limited to 'net/dns_resolver/internal.h') diff --git a/net/dns_resolver/internal.h b/net/dns_resolver/internal.h new file mode 100644 index 000000000..d0d8edcea --- /dev/null +++ b/net/dns_resolver/internal.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (c) 2010 Wang Lei + * Author(s): Wang Lei (wang840925@gmail.com). All Rights Reserved. + * + * Internal DNS Rsolver stuff + */ + +#include +#include +#include + +/* + * Layout of key payload words. + */ +enum { + dns_key_data, + dns_key_error, +}; + +/* + * dns_key.c + */ +extern const struct cred *dns_resolver_cache; + +/* + * debug tracing + */ +extern unsigned int dns_resolver_debug; + +#define kdebug(FMT, ...) \ +do { \ + if (unlikely(dns_resolver_debug)) \ + printk(KERN_DEBUG "[%-6.6s] "FMT"\n", \ + current->comm, ##__VA_ARGS__); \ +} while (0) + +#define kenter(FMT, ...) kdebug("==> %s("FMT")", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) kdebug("<== %s()"FMT"", __func__, ##__VA_ARGS__) -- cgit v1.3.1