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, 154 insertions, 0 deletions

diff --git a/security/selinux/genheaders.c b/security/selinux/genheaders.c
new file mode 100644
index 000000000..3834d7eb0
--- /dev/null
+++ b/security/selinux/genheaders.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+
+struct security_class_mapping {
+	const char *name;
+	const char *perms[sizeof(unsigned) * 8 + 1];
+};
+
+#include "classmap.h"
+#include "initial_sid_to_string.h"
+
+const char *progname;
+
+static void usage(void)
+{
+	printf("usage: %s flask.h av_permissions.h\n", progname);
+	exit(1);
+}
+
+static char *stoupperx(const char *s)
+{
+	char *s2 = strdup(s);
+	char *p;
+
+	if (!s2) {
+		fprintf(stderr, "%s:  out of memory\n", progname);
+		exit(3);
+	}
+
+	for (p = s2; *p; p++)
+		*p = toupper(*p);
+	return s2;
+}
+
+int main(int argc, char *argv[])
+{
+	int i, j;
+	int isids_len;
+	FILE *fout;
+
+	progname = argv[0];
+
+	if (argc < 3)
+		usage();
+
+	fout = fopen(argv[1], "w");
+	if (!fout) {
+		fprintf(stderr, "Could not open %s for writing:  %s\n",
+			argv[1], strerror(errno));
+		exit(2);
+	}
+
+	fprintf(fout, "/* This file is automatically generated.  Do not edit. */\n");
+	fprintf(fout, "#ifndef _SELINUX_FLASK_H_\n#define _SELINUX_FLASK_H_\n\n");
+
+	for (i = 0; secclass_map[i].name; i++) {
+		char *name = stoupperx(secclass_map[i].name);
+
+		fprintf(fout, "#define SECCLASS_%-39s %2d\n", name, i+1);
+		free(name);
+	}
+
+	fprintf(fout, "\n");
+
+	isids_len = sizeof(initial_sid_to_string) / sizeof(char *);
+	for (i = 1; i < isids_len; i++) {
+		const char *s = initial_sid_to_string[i];
+		if (s) {
+			char *sidname = stoupperx(s);
+
+			fprintf(fout, "#define SECINITSID_%-39s %2d\n", sidname, i);
+			free(sidname);
+		}
+	}
+	fprintf(fout, "\n#define SECINITSID_NUM %d\n", i-1);
+	fprintf(fout, "\nstatic inline bool security_is_socket_class(u16 kern_tclass)\n");
+	fprintf(fout, "{\n");
+	fprintf(fout, "\tbool sock = false;\n\n");
+	fprintf(fout, "\tswitch (kern_tclass) {\n");
+	for (i = 0; secclass_map[i].name; i++) {
+		static char s[] = "SOCKET";
+		int len, l;
+		char *name = stoupperx(secclass_map[i].name);
+
+		len = strlen(name);
+		l = sizeof(s) - 1;
+		if (len >= l && memcmp(name + len - l, s, l) == 0)
+			fprintf(fout, "\tcase SECCLASS_%s:\n", name);
+		free(name);
+	}
+	fprintf(fout, "\t\tsock = true;\n");
+	fprintf(fout, "\t\tbreak;\n");
+	fprintf(fout, "\tdefault:\n");
+	fprintf(fout, "\t\tbreak;\n");
+	fprintf(fout, "\t}\n\n");
+	fprintf(fout, "\treturn sock;\n");
+	fprintf(fout, "}\n");
+
+	fprintf(fout, "\n#endif\n");
+
+	if (fclose(fout) != 0) {
+		fprintf(stderr, "Could not successfully close %s:  %s\n",
+			argv[1], strerror(errno));
+		exit(4);
+	}
+
+	fout = fopen(argv[2], "w");
+	if (!fout) {
+		fprintf(stderr, "Could not open %s for writing:  %s\n",
+			argv[2], strerror(errno));
+		exit(5);
+	}
+
+	fprintf(fout, "/* This file is automatically generated.  Do not edit. */\n");
+	fprintf(fout, "#ifndef _SELINUX_AV_PERMISSIONS_H_\n#define _SELINUX_AV_PERMISSIONS_H_\n\n");
+
+	for (i = 0; secclass_map[i].name; i++) {
+		const struct security_class_mapping *map = &secclass_map[i];
+		int len;
+		char *name = stoupperx(map->name);
+
+		len = strlen(name);
+		for (j = 0; map->perms[j]; j++) {
+			char *permname;
+
+			if (j >= 32) {
+				fprintf(stderr, "Too many permissions to fit into an access vector at (%s, %s).\n",
+					map->name, map->perms[j]);
+				exit(5);
+			}
+			permname = stoupperx(map->perms[j]);
+			fprintf(fout, "#define %s__%-*s 0x%08xU\n", name,
+				39-len, permname, 1U<<j);
+			free(permname);
+		}
+		free(name);
+	}
+
+	fprintf(fout, "\n#endif\n");
+
+	if (fclose(fout) != 0) {
+		fprintf(stderr, "Could not successfully close %s:  %s\n",
+			argv[2], strerror(errno));
+		exit(6);
+	}
+
+	exit(0);
+}