kernel/linux.git/security, branch v4.19.27

KEYS: always initialize keyring_index_key::desc_len

2019-02-27T09:09:00+00:00

commit ede0fa98a900e657d1fcd80b50920efc896c1a4c upstream. syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() called from construct_alloc_key() during sys_request_key(), because the length of the key description was never calculated. The problem is that we rely on ->desc_len being initialized by search_process_keyrings(), specifically by search_nested_keyrings(). But, if the process isn't subscribed to any keyrings that never happens. Fix it by always initializing keyring_index_key::desc_len as soon as the description is set, like we already do in some places. The following program reproduces the BUG_ON() when it's run as root and no session keyring has been installed. If it doesn't work, try removing pam_keyinit.so from /etc/pam.d/login and rebooting. #include #include #include int main(void) { int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); keyctl_setperm(id, KEY_OTH_WRITE); setreuid(5000, 5000); request_key("user", "desc", "", id); } Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") Signed-off-by: Eric Biggers Signed-off-by: David Howells Cc: stable@vger.kernel.org Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

KEYS: allow reaching the keys quotas exactly

2019-02-27T09:08:50+00:00

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@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

smack: fix access permissions for keyring

2019-02-12T18:47:05+00:00

[ Upstream commit 5b841bfab695e3b8ae793172a9ff7990f99cc3e2 ] Function smack_key_permission() only issues smack requests for the following operations: - KEY_NEED_READ (issues MAY_READ) - KEY_NEED_WRITE (issues MAY_WRITE) - KEY_NEED_LINK (issues MAY_WRITE) - KEY_NEED_SETATTR (issues MAY_WRITE) A blank smack request is issued in all other cases, resulting in smack access being granted if there is any rule defined between subject and object, or denied with -EACCES otherwise. Request MAY_READ access for KEY_NEED_SEARCH and KEY_NEED_VIEW. Fix the logic in the unlikely case when both MAY_READ and MAY_WRITE are needed. Validate access permission field for valid contents. Signed-off-by: Zoran Markovic Signed-off-by: Casey Schaufler Cc: Casey Schaufler Cc: James Morris Cc: "Serge E. Hallyn" Signed-off-by: Sasha Levin

selinux: always allow mounting submounts

2019-01-26T08:32:36+00:00

[ Upstream commit 2cbdcb882f97a45f7475c67ac6257bbc16277dfe ] If a superblock has the MS_SUBMOUNT flag set, we should always allow mounting it. These mounts are done automatically by the kernel either as part of mounting some parent mount (e.g. debugfs always mounts tracefs under "tracing" for compatibility) or they are mounted automatically as needed on subdirectory accesses (e.g. NFS crossmnt mounts). Since such automounts are either an implicit consequence of the parent mount (which is already checked) or they can happen during regular accesses (where it doesn't make sense to check against the current task's context), the mount permission check should be skipped for them. Without this patch, attempts to access contents of an automounted directory can cause unexpected SELinux denials. In the current kernel tree, the MS_SUBMOUNT flag is set only via vfs_submount(), which is called only from the following places: - AFS, when automounting special "symlinks" referencing other cells - CIFS, when automounting "referrals" - NFS, when automounting subtrees - debugfs, when automounting tracefs In all cases the submounts are meant to be transparent to the user and it makes sense that if mounting the master is allowed, then so should be the automounts. Note that CAP_SYS_ADMIN capability checking is already skipped for (SB_KERNMOUNT|SB_SUBMOUNT) in: - sget_userns() in fs/super.c: if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && !(type->fs_flags & FS_USERNS_MOUNT) && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); - sget() in fs/super.c: /* Ensure the requestor has permissions over the target filesystem */ if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); Verified internally on patched RHEL 7.6 with a reproducer using NFS+httpd and selinux-tesuite. Fixes: 93faccbbfa95 ("fs: Better permission checking for submounts") Signed-off-by: Ondrej Mosnacek Signed-off-by: Paul Moore Signed-off-by: Sasha Levin

selinux: fix GPF on invalid policy

2019-01-22T20:40:35+00:00

commit 5b0e7310a2a33c06edc7eb81ffc521af9b2c5610 upstream. levdatum->level can be NULL if we encounter an error while loading the policy during sens_read prior to initializing it. Make sure sens_destroy handles that case correctly. Reported-by: syzbot+6664500f0f18f07a5c0e@syzkaller.appspotmail.com Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

LSM: Check for NULL cred-security on free

2019-01-22T20:40:35+00:00

commit a5795fd38ee8194451ba3f281f075301a3696ce2 upstream. From: Casey Schaufler Check that the cred security blob has been set before trying to clean it up. There is a case during credential initialization that could result in this. Signed-off-by: Casey Schaufler Acked-by: John Johansen Signed-off-by: James Morris Reported-by: syzbot+69ca07954461f189e808@syzkaller.appspotmail.com Signed-off-by: Greg Kroah-Hartman

Yama: Check for pid death before checking ancestry

2019-01-22T20:40:32+00:00

commit 9474f4e7cd71a633fa1ef93b7daefd44bbdfd482 upstream. It's possible that a pid has died before we take the rcu lock, in which case we can't walk the ancestry list as it may be detached. Instead, check for death first before doing the walk. Reported-by: syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com Fixes: 2d514487faf1 ("security: Yama LSM") Cc: stable@vger.kernel.org Suggested-by: Oleg Nesterov Signed-off-by: Kees Cook Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

selinux: policydb - fix byte order and alignment issues

2019-01-13T08:51:07+00:00

commit 5df275cd4cf51c86d49009f1397132f284ba515e upstream. Do the LE conversions before doing the Infiniband-related range checks. The incorrect checks are otherwise causing a failure to load any policy with an ibendportcon rule on BE systems. This can be reproduced by running (on e.g. ppc64): cat >my_module.cil < Cc: Eli Cohen Cc: James Morris Cc: Doug Ledford Cc: # 4.13+ Fixes: a806f7a1616f ("selinux: Create policydb version for Infiniband support") Signed-off-by: Ondrej Mosnacek Acked-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

selinux: add support for RTM_NEWCHAIN, RTM_DELCHAIN, and RTM_GETCHAIN

2018-12-08T11:59:08+00:00

commit 598e1a42e9626213565d3b22ea948ce78556512a upstream. Commit 32a4f5ecd738 ("net: sched: introduce chain object to uapi") added new RTM_* definitions without properly updating SELinux, this patch adds the necessary SELinux support. While there was a BUILD_BUG_ON() in the SELinux code to protect from exactly this case, it was bypassed in the broken commit. In order to hopefully prevent this from happening in the future, add additional comments which provide some instructions on how to resolve the BUILD_BUG_ON() failures. Fixes: 32a4f5ecd738 ("net: sched: introduce chain object to uapi") Cc: # 4.19 Acked-by: David S. Miller Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

selinux: Add __GFP_NOWARN to allocation at str_read()

2018-12-01T08:37:27+00:00

commit 4458bba09788e70e8fb39ad003f087cd9dfbd6ac upstream. syzbot is hitting warning at str_read() [1] because len parameter can become larger than KMALLOC_MAX_SIZE. We don't need to emit warning for this case. [1] https://syzkaller.appspot.com/bug?id=7f2f5aad79ea8663c296a2eedb81978401a908f0 Signed-off-by: Tetsuo Handa Reported-by: syzbot Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman