Red Hat Security Advisory: kernel security and bug fix update

Important

nfsd in the Linux kernel before 2.6.28.9 does not drop the CAP_MKNOD capability before handling a user request in a thread, which allows local users to create device nodes, as demonstrated on a filesystem that has been exported with the root_squash option.

The (1) agp_generic_alloc_page and (2) agp_generic_alloc_pages functions in drivers/char/agp/generic.c in the agp subsystem in the Linux kernel before 2.6.30-rc3 do not zero out pages that may later be available to a user-space process, which allows local users to obtain sensitive information by reading these pages.

Buffer overflow in fs/cifs/connect.c in CIFS in the Linux kernel 2.6.29 and earlier allows remote attackers to cause a denial of service (crash) via a long nativeFileSystem field in a Tree Connect response to an SMB mount request.

CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer

The nfs_permission function in fs/nfs/dir.c in the NFS client implementation in the Linux kernel 2.6.29.3 and earlier, when atomic_open is available, does not check execute (aka EXEC or MAY_EXEC) permission bits, which allows local users to bypass permissions and execute files, as demonstrated by files on an NFSv4 fileserver.

Multiple buffer overflows in the cifs subsystem in the Linux kernel before 2.6.29.4 allow remote CIFS servers to cause a denial of service (memory corruption) and possibly have unspecified other impact via (1) a malformed Unicode string, related to Unicode string area alignment in fs/cifs/sess.c; or (2) long Unicode characters, related to fs/cifs/cifssmb.c and the cifs_readdir function in fs/cifs/readdir.c.

CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer

The hypervisor_callback function in Xen, possibly before 3.4.0, as applied to the Linux kernel 2.6.30-rc4, 2.6.18, and probably other versions allows guest user applications to cause a denial of service (kernel oops) of the guest OS by triggering a segmentation fault in "certain address ranges."

The get_random_int function in drivers/char/random.c in the Linux kernel before 2.6.30 produces insufficiently random numbers, which allows attackers to predict the return value, and possibly defeat protection mechanisms based on randomization, via vectors that leverage the function's tendency to "return the same value over and over again for long stretches of time."

CWE-330 - Use of Insufficiently Random Values