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| author | Eric Biggers <ebiggers@google.com> | 2017-04-18 15:31:09 +0100 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2017-04-18 15:31:49 +0100 |
| commit | c9f838d104fed6f2f61d68164712e3204bf5271b (patch) | |
| tree | 11f3973c37a4070994d1f64ed444a233ef7f10b4 /security/keys/keyctl.c | |
| parent | c1644fe041ebaf6519f6809146a77c3ead9193af (diff) | |
| download | linux-c9f838d104fed6f2f61d68164712e3204bf5271b.tar.gz linux-c9f838d104fed6f2f61d68164712e3204bf5271b.tar.bz2 linux-c9f838d104fed6f2f61d68164712e3204bf5271b.zip | |
KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings
This fixes CVE-2017-7472.
Running the following program as an unprivileged user exhausts kernel
memory by leaking thread keyrings:
#include <keyutils.h>
int main()
{
for (;;)
keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_THREAD_KEYRING);
}
Fix it by only creating a new thread keyring if there wasn't one before.
To make things more consistent, make install_thread_keyring_to_cred()
and install_process_keyring_to_cred() both return 0 if the corresponding
keyring is already present.
Fixes: d84f4f992cbd ("CRED: Inaugurate COW credentials")
Cc: stable@vger.kernel.org # 2.6.29+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'security/keys/keyctl.c')
| -rw-r--r-- | security/keys/keyctl.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index ab082a2e8fdd..4ad3212adebe 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1258,8 +1258,8 @@ error: * Read or set the default keyring in which request_key() will cache keys and * return the old setting. * - * If a process keyring is specified then this will be created if it doesn't - * yet exist. The old setting will be returned if successful. + * If a thread or process keyring is specified then it will be created if it + * doesn't yet exist. The old setting will be returned if successful. */ long keyctl_set_reqkey_keyring(int reqkey_defl) { @@ -1284,11 +1284,8 @@ long keyctl_set_reqkey_keyring(int reqkey_defl) case KEY_REQKEY_DEFL_PROCESS_KEYRING: ret = install_process_keyring_to_cred(new); - if (ret < 0) { - if (ret != -EEXIST) - goto error; - ret = 0; - } + if (ret < 0) + goto error; goto set; case KEY_REQKEY_DEFL_DEFAULT: |