linux-stable.git/security, branch v5.4.18

tomoyo: Use atomic_t for statistics counter

2020-02-05T21:22:41+00:00

commit a8772fad0172aeae339144598b809fd8d4823331 upstream.

syzbot is reporting that there is a race at tomoyo_stat_update() [1].
Although it is acceptable to fail to track exact number of times policy
was updated, convert to atomic_t because this is not a hot path.

[1] https://syzkaller.appspot.com/bug?id=a4d7b973972eeed410596e6604580e0133b0fc04

Reported-by: syzbot 
Signed-off-by: Tetsuo Handa 
Signed-off-by: Greg Kroah-Hartman

tomoyo: Suppress RCU warning at list_for_each_entry_rcu().

2020-01-17T18:49:05+00:00

[ Upstream commit 6bd5ce6089b561f5392460bfb654dea89356ab1b ]

John Garry has reported that allmodconfig kernel on arm64 causes flood of
"RCU-list traversed in non-reader section!!" warning. I don't know what
change caused this warning, but this warning is safe because TOMOYO uses
SRCU lock instead. Let's suppress this warning by explicitly telling that
the caller is holding SRCU lock.

Reported-and-tested-by: John Garry 
Signed-off-by: Tetsuo Handa 
Signed-off-by: Sasha Levin

apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock

2020-01-09T09:20:00+00:00

commit 8c62ed27a12c00e3db1c9f04bc0f272bdbb06734 upstream.

aa_xattrs_match() is unfortunately calling vfs_getxattr_alloc() from a
context protected by an rcu_read_lock. This can not be done as
vfs_getxattr_alloc() may sleep regardles of the gfp_t value being
passed to it.

Fix this by breaking the rcu_read_lock on the policy search when the
xattr match feature is requested and restarting the search if a policy
changes occur.

Fixes: 8e51f9087f40 ("apparmor: Add support for attaching profiles via xattr, presence and value")
Reported-by: Jia-Ju Bai 
Reported-by: Al Viro 
Signed-off-by: John Johansen 
Signed-off-by: Greg Kroah-Hartman

tomoyo: Don't use nifty names on sockets.

2020-01-04T18:18:42+00:00

commit 6f7c41374b62fd80bbd8aae3536c43688c54d95e upstream.

syzbot is reporting that use of SOCKET_I()->sk from open() can result in
use after free problem [1], for socket's inode is still reachable via
/proc/pid/fd/n despite destruction of SOCKET_I()->sk already completed.

At first I thought that this race condition applies to only open/getattr
permission checks. But James Morris has pointed out that there are more
permission checks where this race condition applies to. Thus, get rid of
tomoyo_get_socket_name() instead of conditionally bypassing permission
checks on sockets. As a side effect of this patch,
"socket:[family=\$:type=\$:protocol=\$]" in the policy files has to be
rewritten to "socket:[\$]".

[1] https://syzkaller.appspot.com/bug?id=73d590010454403d55164cca23bd0565b1eb3b74

Signed-off-by: Tetsuo Handa 
Reported-by: syzbot 
Reported-by: James Morris 
Signed-off-by: Greg Kroah-Hartman

apparmor: fix unsigned len comparison with less than zero

2020-01-04T18:18:22+00:00

[ Upstream commit 00e0590dbaec6f1bcaa36a85467d7e3497ced522 ]

The sanity check in macro update_for_len checks to see if len
is less than zero, however, len is a size_t so it can never be
less than zero, so this sanity check is a no-op.  Fix this by
making len a ssize_t so the comparison will work and add ulen
that is a size_t copy of len so that the min() macro won't
throw warnings about comparing different types.

Addresses-Coverity: ("Macro compares unsigned to 0")
Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels")
Signed-off-by: Colin Ian King 
Signed-off-by: John Johansen 
Signed-off-by: Sasha Levin

efi/efi_test: Lock down /dev/efi_test and require CAP_SYS_ADMIN

2019-10-31T08:40:21+00:00

The driver exposes EFI runtime services to user-space through an IOCTL
interface, calling the EFI services function pointers directly without
using the efivar API.

Disallow access to the /dev/efi_test character device when the kernel is
locked down to prevent arbitrary user-space to call EFI runtime services.

Also require CAP_SYS_ADMIN to open the chardev to prevent unprivileged
users to call the EFI runtime services, instead of just relying on the
chardev file mode bits for this.

The main user of this driver is the fwts [0] tool that already checks if
the effective user ID is 0 and fails otherwise. So this change shouldn't
cause any regression to this tool.

[0]: https://wiki.ubuntu.com/FirmwareTestSuite/Reference/uefivarinfo

Signed-off-by: Javier Martinez Canillas 
Signed-off-by: Ard Biesheuvel 
Acked-by: Laszlo Ersek 
Acked-by: Matthew Garrett 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-7-ardb@kernel.org
Signed-off-by: Ingo Molnar

Merge tag 'selinux-pr-20191007' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

2019-10-08T17:51:37+00:00

Pull selinuxfix from Paul Moore:
 "One patch to ensure we don't copy bad memory up into userspace"

* tag 'selinux-pr-20191007' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix context string corruption in convert_context()

integrity: remove pointless subdir-$(CONFIG_...)

2019-10-05T06:29:49+00:00

The ima/ and evm/ sub-directories contain built-in objects, so
obj-$(CONFIG_...) is the correct way to descend into them.

subdir-$(CONFIG_...) is redundant.

Signed-off-by: Masahiro Yamada

integrity: remove unneeded, broken attempt to add -fshort-wchar

2019-10-05T06:29:49+00:00

I guess commit 15ea0e1e3e18 ("efi: Import certificates from UEFI Secure
Boot") attempted to add -fshort-wchar for building load_uefi.o, but it
has never worked as intended.

load_uefi.o is created in the platform_certs/ sub-directory. If you
really want to add -fshort-wchar, the correct code is:

  $(obj)/platform_certs/load_uefi.o: KBUILD_CFLAGS += -fshort-wchar

But, you do not need to fix it.

Commit 8c97023cf051 ("Kbuild: use -fshort-wchar globally") had already
added -fshort-wchar globally. This code was unneeded in the first place.

Signed-off-by: Masahiro Yamada

selinux: fix context string corruption in convert_context()

2019-10-03T18:13:36+00:00

string_to_context_struct() may garble the context string, so we need to
copy back the contents again from the old context struct to avoid
storing the corrupted context.

Since string_to_context_struct() tokenizes (and therefore truncates) the
context string and we are later potentially copying it with kstrdup(),
this may eventually cause pieces of uninitialized kernel memory to be
disclosed to userspace (when copying to userspace based on the stored
length and not the null character).

How to reproduce on Fedora and similar:
    # dnf install -y memcached
    # systemctl start memcached
    # semodule -d memcached
    # load_policy
    # load_policy
    # systemctl stop memcached
    # ausearch -m AVC
    type=AVC msg=audit(1570090572.648:313): avc:  denied  { signal } for  pid=1 comm="systemd" scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=process permissive=0 trawcon=73797374656D5F75007400000000000070BE6E847296FFFF726F6D000096FFFF76

Cc: stable@vger.kernel.org
Reported-by: Milos Malik 
Fixes: ee1a84fdfeed ("selinux: overhaul sidtab to fix bug and improve performance")
Signed-off-by: Ondrej Mosnacek 
Acked-by: Stephen Smalley 
Signed-off-by: Paul Moore