Linux

It was discovered in the Linux kernel before 4.11-rc8 that root can gain direct access to an internal keyring, such as '.dns_resolver' in RHEL-7 or '.builtin_trusted_keys' upstream, by joining it as its session keyring. This allows root to bypass module signature verification by adding a new public key of its own devising to the keyring.Show less

An issue was discovered in the __ns_get_path function in fs/nsfs.c in the Linux kernel before 4.11. Due to a race condition when accessing files, a Use After Free condition can occur. This also affects all Android releases from CAF using the Linux kernel (Android for MSM, Firefox OS for MSM, QRD Android) before security patch level 2018-07-05.Show less

An integer overflow in the uvesafb_setcmap function in drivers/video/fbdev/uvesafb.c in the Linux kernel before 4.17.4 could result in local attackers being able to crash the kernel or potentially elevate privileges because kmalloc_array is not used.Show less

The inode_init_owner function in fs/inode.c in the Linux kernel through 3.16 allows local users to create files with an unintended group ownership, in a scenario where a directory is SGID to a certain group and is writable by a user who is not a member of that group. Here, the non-member can trigger creation of a plain file whose group ownership is that group. The intended behavior was that the non-member can trigger creation of a directory (but not a plain file) whose group ownership is that group. The non-member can escalate privileges by making the plain file executable and SGID.Show less

An issue was discovered in fs/f2fs/inline.c in the Linux kernel through 4.4. A denial of service (out-of-bounds memory access and BUG) can occur for a modified f2fs filesystem image in which an inline inode contains an invalid reserved blkaddr.Show less

An issue was discovered in fs/f2fs/inode.c in the Linux kernel through 4.17.3. A denial of service (slab out-of-bounds read and BUG) can occur for a modified f2fs filesystem image in which FI_EXTRA_ATTR is set in an inode.Show less

An issue was discovered in fs/f2fs/super.c in the Linux kernel through 4.17.3. There is an out-of-bounds read or a divide-by-zero error for an incorrect user_block_count in a corrupted f2fs image, leading to a denial of service (BUG).Show less

An issue was discovered in fs/f2fs/super.c in the Linux kernel through 4.14. A denial of service (out-of-bounds memory access and BUG) can occur upon encountering an abnormal bitmap size when mounting a crafted f2fs image.Show less

An issue was discovered in fs/xfs/libxfs/xfs_inode_buf.c in the Linux kernel through 4.17.3. A denial of service (memory corruption and BUG) can occur for a corrupted xfs image upon encountering an inode that is in extent format, but has more extents than fit in the inode fork.Show less

An issue was discovered in fs/xfs/xfs_icache.c in the Linux kernel through 4.17.3. There is a NULL pointer dereference and panic in lookup_slow() on a NULL inode->i_ops pointer when doing pathwalks on a corrupted xfs image. This occurs because of a lack of proper validation that cached inodes are free during allocation.Show less

An issue was discovered in the Linux kernel through 4.17.3. An Integer Overflow in kernel/time/posix-timers.c in the POSIX timer code is caused by the way the overrun accounting works. Depending on interval and expiry time values, the overrun can be larger than INT_MAX, but the accounting is int based. This basically makes the accounting values, which are visible to user space via timer_getoverrun(2) and siginfo::si_overrun, random. For example, a local user can cause a denial of service (signed integer overflow) via crafted mmap, futex, timer_create, and timer_settime system calls.Show less

ntfs_attr_find in the ntfs.ko filesystem driver in the Linux kernel 4.15.0 allows attackers to trigger a stack-based out-of-bounds write and cause a denial of service (kernel oops or panic) or possibly have unspecified other impact via a crafted ntfs filesystem.Show less

ntfs_end_buffer_async_read in the ntfs.ko filesystem driver in the Linux kernel 4.15.0 allows attackers to trigger a stack-based out-of-bounds write and cause a denial of service (kernel oops or panic) or possibly have unspecified other impact via a crafted ntfs filesystem.Show less

ntfs_read_locked_inode in the ntfs.ko filesystem driver in the Linux kernel 4.15.0 allows attackers to trigger a use-after-free read and possibly cause a denial of service (kernel oops or panic) via a crafted ntfs filesystem.Show less

In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested virtualization is used, local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL.Show less

Linux Kernel version 3.18 to 4.16 incorrectly handles an SG_IO ioctl on /dev/sg0 with dxfer_direction=SG_DXFER_FROM_DEV and an empty 6-byte cmdp. This may lead to copying up to 1000 kernel heap pages to the userspace. This has been fixed upstream in https://github.com/torvalds/linux/commit/a45b599ad808c3c982fdcdc12b0b8611c2f92824 already. The problem has limited scope, as users don't usually have permissions to access SCSI devices. On the other hand, e.g. the Nero user manual suggests doing `chmod o+r+w /dev/sg*` to make the devices accessible. NOTE: third parties dispute the relevance of this report, noting that the requirement for an attacker to have both the CAP_SYS_ADMIN and CAP_SYS_RAWIO capabilities makes it "virtually impossible to exploit.Show less