android_kernel_motorola_sm6375/security
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Waiman Long 419d8fb163 KEYS: Avoid false positive ENOMEM error on key read
[ Upstream commit 4f0882491a148059a52480e753b7f07fc550e188 ]

By allocating a kernel buffer with a user-supplied buffer length, it
is possible that a false positive ENOMEM error may be returned because
the user-supplied length is just too large even if the system do have
enough memory to hold the actual key data.

Moreover, if the buffer length is larger than the maximum amount of
memory that can be returned by kmalloc() (2^(MAX_ORDER-1) number of
pages), a warning message will also be printed.

To reduce this possibility, we set a threshold (PAGE_SIZE) over which we
do check the actual key length first before allocating a buffer of the
right size to hold it. The threshold is arbitrary, it is just used to
trigger a buffer length check. It does not limit the actual key length
as long as there is enough memory to satisfy the memory request.

To further avoid large buffer allocation failure due to page
fragmentation, kvmalloc() is used to allocate the buffer so that vmapped
pages can be used when there is not a large enough contiguous set of
pages available for allocation.

In the extremely unlikely scenario that the key keeps on being changed
and made longer (still <= buflen) in between 2 __keyctl_read_key()
calls, the __keyctl_read_key() calling loop in keyctl_read_key() may
have to be iterated a large number of times, but definitely not infinite.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-29 16:33:11 +02:00
..
apparmor apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock 2020-01-09 10:20:00 +01:00
integrity efi: Only print errors about failing to get certs if EFI vars are found 2020-03-12 13:00:14 +01:00
keys KEYS: Avoid false positive ENOMEM error on key read 2020-04-29 16:33:11 +02:00
loadpin
lockdown
safesetid
selinux selinux: ensure we cleanup the internal AVC counters on error in avc_update() 2020-02-24 08:36:39 +01:00
smack broken ping to ipv6 linklocal addresses on debian buster 2020-02-11 04:35:43 -08:00
tomoyo tomoyo: Use atomic_t for statistics counter 2020-02-05 21:22:41 +00:00
yama
commoncap.c
device_cgroup.c
inode.c
Kconfig
Kconfig.hardening
lsm_audit.c
Makefile
min_addr.c
security.c