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, 213 insertions, 0 deletions

diff --git a/fs/jffs2/summary.h b/fs/jffs2/summary.h
new file mode 100644
index 000000000..36d9a1280
--- /dev/null
+++ b/fs/jffs2/summary.h
@@ -0,0 +1,213 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2004  Ferenc Havasi <havasi@inf.u-szeged.hu>,
+ *		     Zoltan Sogor <weth@inf.u-szeged.hu>,
+ *		     Patrik Kluba <pajko@halom.u-szeged.hu>,
+ *		     University of Szeged, Hungary
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#ifndef JFFS2_SUMMARY_H
+#define JFFS2_SUMMARY_H
+
+/* Limit summary size to 64KiB so that we can kmalloc it. If the summary
+   is larger than that, we have to just ditch it and avoid using summary
+   for the eraseblock in question... and it probably doesn't hurt us much
+   anyway. */
+#define MAX_SUMMARY_SIZE 65536
+
+#include <linux/uio.h>
+#include <linux/jffs2.h>
+
+#define BLK_STATE_ALLFF		0
+#define BLK_STATE_CLEAN		1
+#define BLK_STATE_PARTDIRTY	2
+#define BLK_STATE_CLEANMARKER	3
+#define BLK_STATE_ALLDIRTY	4
+#define BLK_STATE_BADBLOCK	5
+
+#define JFFS2_SUMMARY_NOSUM_SIZE 0xffffffff
+#define JFFS2_SUMMARY_INODE_SIZE (sizeof(struct jffs2_sum_inode_flash))
+#define JFFS2_SUMMARY_DIRENT_SIZE(x) (sizeof(struct jffs2_sum_dirent_flash) + (x))
+#define JFFS2_SUMMARY_XATTR_SIZE (sizeof(struct jffs2_sum_xattr_flash))
+#define JFFS2_SUMMARY_XREF_SIZE (sizeof(struct jffs2_sum_xref_flash))
+
+/* Summary structures used on flash */
+
+struct jffs2_sum_unknown_flash
+{
+	jint16_t nodetype;	/* node type */
+};
+
+struct jffs2_sum_inode_flash
+{
+	jint16_t nodetype;	/* node type */
+	jint32_t inode;		/* inode number */
+	jint32_t version;	/* inode version */
+	jint32_t offset;	/* offset on jeb */
+	jint32_t totlen; 	/* record length */
+} __attribute__((packed));
+
+struct jffs2_sum_dirent_flash
+{
+	jint16_t nodetype;	/* == JFFS_NODETYPE_DIRENT */
+	jint32_t totlen;	/* record length */
+	jint32_t offset;	/* offset on jeb */
+	jint32_t pino;		/* parent inode */
+	jint32_t version;	/* dirent version */
+	jint32_t ino; 		/* == zero for unlink */
+	uint8_t nsize;		/* dirent name size */
+	uint8_t type;		/* dirent type */
+	uint8_t name[];	/* dirent name */
+} __attribute__((packed));
+
+struct jffs2_sum_xattr_flash
+{
+	jint16_t nodetype;	/* == JFFS2_NODETYPE_XATR */
+	jint32_t xid;		/* xattr identifier */
+	jint32_t version;	/* version number */
+	jint32_t offset;	/* offset on jeb */
+	jint32_t totlen;	/* node length */
+} __attribute__((packed));
+
+struct jffs2_sum_xref_flash
+{
+	jint16_t nodetype;	/* == JFFS2_NODETYPE_XREF */
+	jint32_t offset;	/* offset on jeb */
+} __attribute__((packed));
+
+union jffs2_sum_flash
+{
+	struct jffs2_sum_unknown_flash u;
+	struct jffs2_sum_inode_flash i;
+	struct jffs2_sum_dirent_flash d;
+	struct jffs2_sum_xattr_flash x;
+	struct jffs2_sum_xref_flash r;
+};
+
+/* Summary structures used in the memory */
+
+struct jffs2_sum_unknown_mem
+{
+	union jffs2_sum_mem *next;
+	jint16_t nodetype;	/* node type */
+};
+
+struct jffs2_sum_inode_mem
+{
+	union jffs2_sum_mem *next;
+	jint16_t nodetype;	/* node type */
+	jint32_t inode;		/* inode number */
+	jint32_t version;	/* inode version */
+	jint32_t offset;	/* offset on jeb */
+	jint32_t totlen; 	/* record length */
+} __attribute__((packed));
+
+struct jffs2_sum_dirent_mem
+{
+	union jffs2_sum_mem *next;
+	jint16_t nodetype;	/* == JFFS_NODETYPE_DIRENT */
+	jint32_t totlen;	/* record length */
+	jint32_t offset;	/* ofset on jeb */
+	jint32_t pino;		/* parent inode */
+	jint32_t version;	/* dirent version */
+	jint32_t ino; 		/* == zero for unlink */
+	uint8_t nsize;		/* dirent name size */
+	uint8_t type;		/* dirent type */
+	uint8_t name[];	/* dirent name */
+} __attribute__((packed));
+
+struct jffs2_sum_xattr_mem
+{
+	union jffs2_sum_mem *next;
+	jint16_t nodetype;
+	jint32_t xid;
+	jint32_t version;
+	jint32_t offset;
+	jint32_t totlen;
+} __attribute__((packed));
+
+struct jffs2_sum_xref_mem
+{
+	union jffs2_sum_mem *next;
+	jint16_t nodetype;
+	jint32_t offset;
+} __attribute__((packed));
+
+union jffs2_sum_mem
+{
+	struct jffs2_sum_unknown_mem u;
+	struct jffs2_sum_inode_mem i;
+	struct jffs2_sum_dirent_mem d;
+	struct jffs2_sum_xattr_mem x;
+	struct jffs2_sum_xref_mem r;
+};
+
+/* Summary related information stored in superblock */
+
+struct jffs2_summary
+{
+	uint32_t sum_size;      /* collected summary information for nextblock */
+	uint32_t sum_num;
+	uint32_t sum_padded;
+	union jffs2_sum_mem *sum_list_head;
+	union jffs2_sum_mem *sum_list_tail;
+
+	jint32_t *sum_buf;	/* buffer for writing out summary */
+};
+
+/* Summary marker is stored at the end of every sumarized erase block */
+
+struct jffs2_sum_marker
+{
+	jint32_t offset;	/* offset of the summary node in the jeb */
+	jint32_t magic; 	/* == JFFS2_SUM_MAGIC */
+};
+
+#define JFFS2_SUMMARY_FRAME_SIZE (sizeof(struct jffs2_raw_summary) + sizeof(struct jffs2_sum_marker))
+
+#ifdef CONFIG_JFFS2_SUMMARY	/* SUMMARY SUPPORT ENABLED */
+
+#define jffs2_sum_active() (1)
+int jffs2_sum_init(struct jffs2_sb_info *c);
+void jffs2_sum_exit(struct jffs2_sb_info *c);
+void jffs2_sum_disable_collecting(struct jffs2_summary *s);
+int jffs2_sum_is_disabled(struct jffs2_summary *s);
+void jffs2_sum_reset_collected(struct jffs2_summary *s);
+void jffs2_sum_move_collected(struct jffs2_sb_info *c, struct jffs2_summary *s);
+int jffs2_sum_add_kvec(struct jffs2_sb_info *c, const struct kvec *invecs,
+			unsigned long count,  uint32_t to);
+int jffs2_sum_write_sumnode(struct jffs2_sb_info *c);
+int jffs2_sum_add_padding_mem(struct jffs2_summary *s, uint32_t size);
+int jffs2_sum_add_inode_mem(struct jffs2_summary *s, struct jffs2_raw_inode *ri, uint32_t ofs);
+int jffs2_sum_add_dirent_mem(struct jffs2_summary *s, struct jffs2_raw_dirent *rd, uint32_t ofs);
+int jffs2_sum_add_xattr_mem(struct jffs2_summary *s, struct jffs2_raw_xattr *rx, uint32_t ofs);
+int jffs2_sum_add_xref_mem(struct jffs2_summary *s, struct jffs2_raw_xref *rr, uint32_t ofs);
+int jffs2_sum_scan_sumnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
+			   struct jffs2_raw_summary *summary, uint32_t sumlen,
+			   uint32_t *pseudo_random);
+
+#else				/* SUMMARY DISABLED */
+
+#define jffs2_sum_active() (0)
+#define jffs2_sum_init(a) (0)
+#define jffs2_sum_exit(a) do { } while (0)
+#define jffs2_sum_disable_collecting(a)
+#define jffs2_sum_is_disabled(a) (0)
+#define jffs2_sum_reset_collected(a) do { } while (0)
+#define jffs2_sum_add_kvec(a,b,c,d) (0)
+#define jffs2_sum_move_collected(a,b) do { } while (0)
+#define jffs2_sum_write_sumnode(a) (0)
+#define jffs2_sum_add_padding_mem(a,b) do { } while (0)
+#define jffs2_sum_add_inode_mem(a,b,c) do { } while (0)
+#define jffs2_sum_add_dirent_mem(a,b,c) do { } while (0)
+#define jffs2_sum_add_xattr_mem(a,b,c) do { } while (0)
+#define jffs2_sum_add_xref_mem(a,b,c) do { } while (0)
+#define jffs2_sum_scan_sumnode(a,b,c,d,e) (0)
+
+#endif /* CONFIG_JFFS2_SUMMARY */
+
+#endif /* JFFS2_SUMMARY_H */