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-rw-r--r--fs/fuse/file.c29
-rw-r--r--fs/fuse/fuse_i.h3
-rw-r--r--fs/fuse/inode.c2
3 files changed, 25 insertions, 9 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 36f92f1..28aa81e 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -161,15 +161,25 @@ static int fuse_release(struct inode *inode, struct file *file)
}
/*
- * It would be nice to scramble the ID space, so that the value of the
- * files_struct pointer is not exposed to userspace. Symmetric crypto
- * functions are overkill, since the inverse function doesn't need to
- * be implemented (though it does have to exist). Is there something
- * simpler?
+ * Scramble the ID space with XTEA, so that the value of the files_struct
+ * pointer is not exposed to userspace.
*/
-static inline u64 fuse_lock_owner_id(fl_owner_t id)
+static u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
{
- return (unsigned long) id;
+ u32 *k = fc->scramble_key;
+ u64 v = (unsigned long) id;
+ u32 v0 = v;
+ u32 v1 = v >> 32;
+ u32 sum = 0;
+ int i;
+
+ for (i = 0; i < 32; i++) {
+ v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
+ sum += 0x9E3779B9;
+ v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
+ }
+
+ return (u64) v0 + ((u64) v1 << 32);
}
static int fuse_flush(struct file *file, fl_owner_t id)
@@ -190,7 +200,7 @@ static int fuse_flush(struct file *file, fl_owner_t id)
req = fuse_get_req_nofail(fc, file);
memset(&inarg, 0, sizeof(inarg));
inarg.fh = ff->fh;
- inarg.lock_owner = fuse_lock_owner_id(id);
+ inarg.lock_owner = fuse_lock_owner_id(fc, id);
req->in.h.opcode = FUSE_FLUSH;
req->in.h.nodeid = get_node_id(inode);
req->in.numargs = 1;
@@ -644,11 +654,12 @@ static void fuse_lk_fill(struct fuse_req *req, struct file *file,
const struct file_lock *fl, int opcode, pid_t pid)
{
struct inode *inode = file->f_dentry->d_inode;
+ struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
struct fuse_lk_in *arg = &req->misc.lk_in;
arg->fh = ff->fh;
- arg->owner = fuse_lock_owner_id(fl->fl_owner);
+ arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
arg->lk.start = fl->fl_start;
arg->lk.end = fl->fl_end;
arg->lk.type = fl->fl_type;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index c862df5..0dbf966 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -359,6 +359,9 @@ struct fuse_conn {
/** O_ASYNC requests */
struct fasync_struct *fasync;
+
+ /** Key for lock owner ID scrambling */
+ u32 scramble_key[4];
};
static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index e21ef8a..5ceb8bd 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/parser.h>
#include <linux/statfs.h>
+#include <linux/random.h>
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Filesystem in Userspace");
@@ -387,6 +388,7 @@ static struct fuse_conn *new_conn(void)
fc->bdi.unplug_io_fn = default_unplug_io_fn;
fc->reqctr = 0;
fc->blocked = 1;
+ get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
}
return fc;
}
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