A flaw was found in the crypto subsystem of the Linux kernel before version kernel-4.15-rc4. The "null skcipher" was being dropped when each af_alg_ctx was freed instead of when the aead_tfm was freed. This can cause the null skcipher to be freed while it is still in use leading to a local user being able to crash the system or possibly escalate privileges.

A flaw was found in the crypto subsystem of the Linux kernel before version kernel-4.15-rc4. The "null skcipher" was being dropped when each af_alg_ctx was freed instead of when the aead_tfm was freed. This can cause the null skcipher to be freed while it is still in use leading to a local user being able to crash the system or possibly escalate privileges.

kernel: v4l2: disabled memory access protection mechanism allowing privilege escalation kernel: Use-after-free in drivers/media/dvb-core/dvb_frontend.c kernel: Salsa20 encryption algorithm does not correctly handle zero-length inputs allowing local attackers to cause denial-of-service kernel: HMAC implementation does not validate that the underlying cryptographic hash algorithm is unkeyed allowing local attackers to cause denial-of-service kernel: Mishandled freeing of instances in pcrypt.c can allow a local user to cause a denial of service kernel: Inifinite loop vulnerability in mm/madvise.c:madvise_willneed() function allows local denial of service kernel: out-of-bounds access in the show_timer function in kernel/time/posix-timers.c kernel: netfilter: xtables NULL pointer dereference in ip6_tables.c:ip6t_do_table() leading to a crash kernel: Out-of-bounds write via userland offsets in ebt_entry struct in netfilter/ebtables.c kernel: NULL pointer dereference in ext4/mballoc.c:ext4_process_freed_data() when mounting crafted ext4 image kernel: NULL pointer dereference in ext4/xattr.c:ext4_xattr_inode_hash() causes crash with crafted ext4 image kernel: out-of-bound access in fs/posix_acl.c:get_acl() causes crash with crafted ext4 image kernel: vhost: Information disclosure in vhost/vhost.c:vhost_new_msg() kernel: fuse-backed file mmap-ed onto process cmdline arguments causes denial of service hw: cpu: speculative store bypass kernel: drivers/block/loop.c mishandles lo_release…

Withdrawn by the publisher.

Affected: Ubuntu:14.04:LTS: linux-azure, Ubuntu:16.04:LTS: linux-azure, Ubuntu:16.04:LTS: linux-gcp, Ubuntu:16.04:LTS: linux-hwe, Ubuntu:18.04:LTS: linux, Ubuntu:18.04:LTS: linux-aws, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-kvm, Ubuntu:18.04:LTS: linux-oem and 1 more

A flaw was found in the crypto subsystem of the Linux kernel before version kernel-4.15-rc4. The "null skcipher" was being dropped when each af_alg_ctx was freed instead of when the aead_tfm was freed. This can cause the null skcipher to be freed while it is still in use leading to a local user being able to crash the system or possibly escalate privileges.