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Diffstat (limited to 'tags/2.6.18-11/30009_keys-serial-num-collision.patch')
-rw-r--r--tags/2.6.18-11/30009_keys-serial-num-collision.patch92
1 files changed, 92 insertions, 0 deletions
diff --git a/tags/2.6.18-11/30009_keys-serial-num-collision.patch b/tags/2.6.18-11/30009_keys-serial-num-collision.patch
new file mode 100644
index 0000000..9875900
--- /dev/null
+++ b/tags/2.6.18-11/30009_keys-serial-num-collision.patch
@@ -0,0 +1,92 @@
+From: David Howells <dhowells@redhat.com>
+Date: Tue, 6 Feb 2007 13:45:51 +0000 (+0000)
+Subject: [PATCH] Keys: Fix key serial number collision handling
+X-Git-Tag: v2.6.21-rc2~42^2~22
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=9ad0830f307bcd8dc285cfae58998d43b21727f4
+
+[PATCH] Keys: Fix key serial number collision handling
+
+Fix the key serial number collision avoidance code in key_alloc_serial().
+
+This didn't use to be so much of a problem as the key serial numbers were
+allocated from a simple incremental counter, and it would have to go through
+two billion keys before it could possibly encounter a collision. However, now
+that random numbers are used instead, collisions are much more likely.
+
+This is fixed by finding a hole in the rbtree where the next unused serial
+number ought to be and using that by going almost back to the top of the
+insertion routine and redoing the insertion with the new serial number rather
+than trying to be clever and attempting to work out the insertion point
+pointer directly.
+
+This fixes kernel BZ #7727.
+
+Signed-off-by: David Howells <dhowells@redhat.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+---
+
+diff --git a/security/keys/key.c b/security/keys/key.c
+index ac9326c..700400d 100644
+--- a/security/keys/key.c
++++ b/security/keys/key.c
+@@ -188,6 +188,7 @@ static inline void key_alloc_serial(struct key *key)
+
+ spin_lock(&key_serial_lock);
+
++attempt_insertion:
+ parent = NULL;
+ p = &key_serial_tree.rb_node;
+
+@@ -202,39 +203,33 @@ static inline void key_alloc_serial(struct key *key)
+ else
+ goto serial_exists;
+ }
+- goto insert_here;
++
++ /* we've found a suitable hole - arrange for this key to occupy it */
++ rb_link_node(&key->serial_node, parent, p);
++ rb_insert_color(&key->serial_node, &key_serial_tree);
++
++ spin_unlock(&key_serial_lock);
++ return;
+
+ /* we found a key with the proposed serial number - walk the tree from
+ * that point looking for the next unused serial number */
+ serial_exists:
+ for (;;) {
+ key->serial++;
+- if (key->serial < 2)
+- key->serial = 2;
+-
+- if (!rb_parent(parent))
+- p = &key_serial_tree.rb_node;
+- else if (rb_parent(parent)->rb_left == parent)
+- p = &(rb_parent(parent)->rb_left);
+- else
+- p = &(rb_parent(parent)->rb_right);
++ if (key->serial < 3) {
++ key->serial = 3;
++ goto attempt_insertion;
++ }
+
+ parent = rb_next(parent);
+ if (!parent)
+- break;
++ goto attempt_insertion;
+
+ xkey = rb_entry(parent, struct key, serial_node);
+ if (key->serial < xkey->serial)
+- goto insert_here;
++ goto attempt_insertion;
+ }
+
+- /* we've found a suitable hole - arrange for this key to occupy it */
+-insert_here:
+- rb_link_node(&key->serial_node, parent, p);
+- rb_insert_color(&key->serial_node, &key_serial_tree);
+-
+- spin_unlock(&key_serial_lock);
+-
+ } /* end key_alloc_serial() */
+
+ /*****************************************************************************/