Commits
Theodore Ts'o committed d4d783d829c
ext4: validate s_reserved_gdt_blocks on mount [ Upstream commit 5b9554dc5bf008ae7f68a52e3d7e76c0920938a2 ] If s_reserved_gdt_blocks is extremely large, it's possible for ext4_init_block_bitmap(), which is called when ext4 sets up an uninitialized block bitmap, to corrupt random kernel memory. Add the same checks which e2fsck has --- it must never be larger than blocksize / sizeof(__u32) --- and then add a backup check in ext4_init_block_bitmap() in case the superblock gets modified after the file system is mounted. Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <alexander.levin@verizon.com>