4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit a08bf91ce28ed3ae7b6fef35d843fef8dc8c2cd9 upstream.
If the sysctl 'kernel.keys.maxkeys' is set to some number n, then
actually users can only add up to 'n - 1' keys. Likewise for
'kernel.keys.maxbytes' and the root_* versions of these sysctls. But
these sysctls are apparently supposed to be *maximums*, as per their
names and all documentation I could find -- the keyrings(7) man page,
Documentation/security/keys/core.rst, and all the mentions of EDQUOT
meaning that the key quota was *exceeded* (as opposed to reached).
Thus, fix the code to allow reaching the quotas exactly.
Fixes: 0b77f5bfb45c ("keys: make the keyring quotas controllable through /proc/sys")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: James Morris <james.morris@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
security/keys/key.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -260,8 +260,8 @@ struct key *key_alloc(struct key_type *t
spin_lock(&user->lock);
if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
- if (user->qnkeys + 1 >= maxkeys ||
- user->qnbytes + quotalen >= maxbytes ||
+ if (user->qnkeys + 1 > maxkeys ||
+ user->qnbytes + quotalen > maxbytes ||
user->qnbytes + quotalen < user->qnbytes)
goto no_quota;
}
