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, 87 insertions, 0 deletions

diff --git a/tools/perf/ui/browser.h b/tools/perf/ui/browser.h
new file mode 100644
index 000000000..9d4404f9b
--- /dev/null
+++ b/tools/perf/ui/browser.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PERF_UI_BROWSER_H_
+#define _PERF_UI_BROWSER_H_ 1
+
+#include <linux/types.h>
+#include <stdarg.h>
+#include <sys/types.h>
+
+#define HE_COLORSET_TOP		50
+#define HE_COLORSET_MEDIUM	51
+#define HE_COLORSET_NORMAL	52
+#define HE_COLORSET_SELECTED	53
+#define HE_COLORSET_JUMP_ARROWS	54
+#define HE_COLORSET_ADDR	55
+#define HE_COLORSET_ROOT	56
+
+struct ui_browser {
+	u64	      index, top_idx;
+	void	      *top, *entries;
+	u16	      y, x, width, height, rows, columns, horiz_scroll;
+	u8	      extra_title_lines;
+	int	      current_color;
+	void	      *priv;
+	char	      *title;
+	char	      *helpline;
+	const char    *no_samples_msg;
+	void 	      (*refresh_dimensions)(struct ui_browser *browser);
+	unsigned int  (*refresh)(struct ui_browser *browser);
+	void	      (*write)(struct ui_browser *browser, void *entry, int row);
+	void	      (*seek)(struct ui_browser *browser, off_t offset, int whence);
+	bool	      (*filter)(struct ui_browser *browser, void *entry);
+	u32	      nr_entries;
+	bool	      navkeypressed;
+	bool	      use_navkeypressed;
+};
+
+int  ui_browser__set_color(struct ui_browser *browser, int color);
+void ui_browser__set_percent_color(struct ui_browser *browser,
+				   double percent, bool current);
+bool ui_browser__is_current_entry(struct ui_browser *browser, unsigned row);
+void ui_browser__refresh_dimensions(struct ui_browser *browser);
+void ui_browser__reset_index(struct ui_browser *browser);
+
+void ui_browser__gotorc_title(struct ui_browser *browser, int y, int x);
+void ui_browser__gotorc(struct ui_browser *browser, int y, int x);
+void ui_browser__write_nstring(struct ui_browser *browser, const char *msg,
+			       unsigned int width);
+void ui_browser__vprintf(struct ui_browser *browser, const char *fmt, va_list args);
+void ui_browser__printf(struct ui_browser *browser, const char *fmt, ...);
+void ui_browser__write_graph(struct ui_browser *browser, int graph);
+void __ui_browser__line_arrow(struct ui_browser *browser, unsigned int column,
+			      u64 start, u64 end);
+void ui_browser__mark_fused(struct ui_browser *browser, unsigned int column,
+			    unsigned int row, int diff, bool arrow_down);
+void __ui_browser__show_title(struct ui_browser *browser, const char *title);
+void ui_browser__show_title(struct ui_browser *browser, const char *title);
+int ui_browser__show(struct ui_browser *browser, const char *title,
+		     const char *helpline, ...);
+void ui_browser__hide(struct ui_browser *browser);
+int ui_browser__refresh(struct ui_browser *browser);
+int ui_browser__run(struct ui_browser *browser, int delay_secs);
+void ui_browser__update_nr_entries(struct ui_browser *browser, u32 nr_entries);
+void ui_browser__handle_resize(struct ui_browser *browser);
+void __ui_browser__vline(struct ui_browser *browser, unsigned int column,
+			 u16 start, u16 end);
+
+int ui_browser__warning(struct ui_browser *browser, int timeout,
+			const char *format, ...);
+int ui_browser__warn_unhandled_hotkey(struct ui_browser *browser, int key, int timeout, const char *help);
+int ui_browser__help_window(struct ui_browser *browser, const char *text);
+bool ui_browser__dialog_yesno(struct ui_browser *browser, const char *text);
+int ui_browser__input_window(const char *title, const char *text, char *input,
+			     const char *exit_msg, int delay_sec);
+struct perf_session;
+int tui__header_window(struct perf_session *session);
+
+void ui_browser__argv_seek(struct ui_browser *browser, off_t offset, int whence);
+unsigned int ui_browser__argv_refresh(struct ui_browser *browser);
+
+void ui_browser__rb_tree_seek(struct ui_browser *browser, off_t offset, int whence);
+unsigned int ui_browser__rb_tree_refresh(struct ui_browser *browser);
+
+void ui_browser__list_head_seek(struct ui_browser *browser, off_t offset, int whence);
+unsigned int ui_browser__list_head_refresh(struct ui_browser *browser);
+
+void ui_browser__init(void);
+#endif /* _PERF_UI_BROWSER_H_ */