openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

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 <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h
new file mode 100644
index 000000000..04ff92684
--- /dev/null
+++ b/tools/perf/util/top.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_TOP_H
+#define __PERF_TOP_H 1
+
+#include "tool.h"
+#include "evswitch.h"
+#include "annotate.h"
+#include "mutex.h"
+#include "ordered-events.h"
+#include "record.h"
+#include <linux/types.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <sys/ioctl.h>
+
+struct evlist;
+struct evsel;
+struct perf_session;
+
+struct perf_top {
+	struct perf_tool   tool;
+	struct evlist *evlist, *sb_evlist;
+	struct record_opts record_opts;
+	struct evswitch	   evswitch;
+	/*
+	 * Symbols will be added here in perf_event__process_sample and will
+	 * get out after decayed.
+	 */
+	u64		   samples, lost, lost_total, drop, drop_total;
+	u64		   kernel_samples, us_samples;
+	u64		   exact_samples;
+	u64		   guest_us_samples, guest_kernel_samples;
+	int		   print_entries, count_filter, delay_secs;
+	int		   max_stack;
+	bool		   hide_kernel_symbols, hide_user_symbols, zero;
+#ifdef HAVE_SLANG_SUPPORT
+	bool		   use_tui;
+#endif
+	bool		   use_stdio;
+	bool		   vmlinux_warned;
+	bool		   dump_symtab;
+	bool		   stitch_lbr;
+	struct hist_entry  *sym_filter_entry;
+	struct evsel 	   *sym_evsel;
+	struct perf_session *session;
+	struct winsize	   winsize;
+	int		   realtime_prio;
+	const char	   *sym_filter;
+	float		   min_percent;
+	unsigned int	   nr_threads_synthesize;
+	const char	   *uid_str;
+
+	struct {
+		struct ordered_events	*in;
+		struct ordered_events	 data[2];
+		bool			 rotate;
+		struct mutex mutex;
+		struct cond cond;
+	} qe;
+};
+
+#define CONSOLE_CLEAR ""
+
+size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size);
+void perf_top__reset_sample_counters(struct perf_top *top);
+#endif /* __PERF_TOP_H */