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Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 

Pull key handling bugfix from James Morris:
 "Fix a race between keyctl_read() and keyctl_revoke()"

* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  KEYS: Fix race between read and revoke
This commit is contained in:
Linus Torvalds 2015-12-28 10:35:19 -08:00
parent 74bf8efb5f b4a1b4f504
commit 2c7143d4f5
1 changed files with 9 additions and 9 deletions
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18
security/keys/keyctl.c
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@ -751,16 +751,16 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
/* the key is probably readable - now try to read it */
can_read_key:
ret = key_validate(key);
if (ret == 0) {
ret = -EOPNOTSUPP;
if (key->type->read) {
/* read the data with the semaphore held (since we
* might sleep) */
down_read(&key->sem);
ret = -EOPNOTSUPP;
if (key->type->read) {
/* Read the data with the semaphore held (since we might sleep)
* to protect against the key being updated or revoked.
*/
down_read(&key->sem);
ret = key_validate(key);
if (ret == 0)
ret = key->type->read(key, buffer, buflen);
up_read(&key->sem);
}
up_read(&key->sem);
}
error2: