Heap-based buffer overflow in the parse_tag_3_packet function in fs/ecryptfs/keystore.c in the eCryptfs subsystem in the Linux kernel before 2.6.30.4 allows local users to cause a denial of service (system crash) or possibly gain privileges via vectors involving a crafted eCryptfs file, related to a large encrypted key size in a Tag 3 packet.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.