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 --- scripts/include/xalloc.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 scripts/include/xalloc.h (limited to 'scripts/include/xalloc.h') diff --git a/scripts/include/xalloc.h b/scripts/include/xalloc.h new file mode 100644 index 000000000..cdadb07d0 --- /dev/null +++ b/scripts/include/xalloc.h @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef XALLOC_H +#define XALLOC_H + +#include +#include + +static inline void *xmalloc(size_t size) +{ + void *p = malloc(size); + + if (!p) + exit(1); + return p; +} + +static inline void *xcalloc(size_t nmemb, size_t size) +{ + void *p = calloc(nmemb, size); + + if (!p) + exit(1); + return p; +} + +static inline void *xrealloc(void *p, size_t size) +{ + p = realloc(p, size); + if (!p) + exit(1); + return p; +} + +static inline char *xstrdup(const char *s) +{ + char *p = strdup(s); + + if (!p) + exit(1); + return p; +} + +static inline char *xstrndup(const char *s, size_t n) +{ + char *p = strndup(s, n); + + if (!p) + exit(1); + return p; +} + +#endif /* XALLOC_H */ -- cgit v1.3.1