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, 76 insertions, 0 deletions

diff --git a/tools/perf/util/block-info.h b/tools/perf/util/block-info.h
new file mode 100644
index 000000000..b9329dc3a
--- /dev/null
+++ b/tools/perf/util/block-info.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_BLOCK_H
+#define __PERF_BLOCK_H
+
+#include <linux/types.h>
+#include "hist.h"
+#include "symbol.h"
+#include "sort.h"
+#include "ui/ui.h"
+
+struct block_info {
+	struct symbol		*sym;
+	u64			start;
+	u64			end;
+	u64			cycles;
+	u64			cycles_aggr;
+	s64			cycles_spark[NUM_SPARKS];
+	u64			total_cycles;
+	int			num;
+	int			num_aggr;
+	int			br_cntr_nr;
+	u64			*br_cntr;
+	struct evsel		*evsel;
+};
+
+struct block_fmt {
+	struct perf_hpp_fmt	fmt;
+	int			idx;
+	int			width;
+	const char		*header;
+	u64			total_cycles;
+	u64			block_cycles;
+};
+
+enum {
+	PERF_HPP_REPORT__BLOCK_TOTAL_CYCLES_PCT,
+	PERF_HPP_REPORT__BLOCK_LBR_CYCLES,
+	PERF_HPP_REPORT__BLOCK_CYCLES_PCT,
+	PERF_HPP_REPORT__BLOCK_AVG_CYCLES,
+	PERF_HPP_REPORT__BLOCK_RANGE,
+	PERF_HPP_REPORT__BLOCK_DSO,
+	PERF_HPP_REPORT__BLOCK_BRANCH_COUNTER,
+	PERF_HPP_REPORT__BLOCK_MAX_INDEX
+};
+
+struct block_report {
+	struct block_hist	hist;
+	u64			cycles;
+	struct block_fmt	fmts[PERF_HPP_REPORT__BLOCK_MAX_INDEX];
+	int			nr_fmts;
+};
+
+void block_info__delete(struct block_info *bi);
+
+int64_t __block_info__cmp(struct hist_entry *left, struct hist_entry *right);
+
+int64_t block_info__cmp(struct perf_hpp_fmt *fmt __maybe_unused,
+			struct hist_entry *left, struct hist_entry *right);
+
+int block_info__process_sym(struct hist_entry *he, struct block_hist *bh,
+			    u64 *block_cycles_aggr, u64 total_cycles,
+			    unsigned int br_cntr_nr);
+
+struct block_report *block_info__create_report(struct evlist *evlist,
+					       u64 total_cycles,
+					       int *block_hpps, int nr_hpps,
+					       int *nr_reps);
+
+void block_info__free_report(struct block_report *reps, int nr_reps);
+
+int report__browse_block_hists(struct block_hist *bh, float min_percent,
+			       struct evsel *evsel, struct perf_env *env);
+
+float block_info__total_cycles_percent(struct hist_entry *he);
+
+#endif /* __PERF_BLOCK_H */