libaslrmalloc | LD_PRELOADed library to randomize malloc and friends

libaslrmalloc is a C library. libaslrmalloc has no bugs, it has no vulnerabilities and it has low support. You can download it from GitHub.

libaslrmalloc is a LD_PRELOADed library which replaces malloc() and other memory allocation functions from C library. The main design goal is not performance or memory consumption but to increase address space layout randomization (ASLR), hence the name. This is achieved by not trying to keep the pages together, forcing the kernel to map pages at random addresses and unmapping old memory immediately when possible. The amount of ALSR depends on processor type, size of allocation and possible user specified alignment (posix_memalign()). Assuming a processor with 48 bits of virtual address space (47 is available to user applications) and no extra alignment restrictions: Size | Lowest randomized bit | Total ---:|---:|---: 16 | 4 | 43 32 | 5 | 42 64 | 6 | 41 128 | 7 | 40 256 | 8 | 39 512 | 9 | 38 1024 | 10 | 37 2048 | 11 | 36 4096+ | 12 | 35. In addition, if the allocation is between the above sizes, the extra space is used to randomize the start address (within alignment restrictions). For example, 1600 bytes fit in a slab of 2048 bytes. There's extra space of 2048 - 1600 = 448 bytes to randomize the start of the allocation, but alignment needs to be taken care of as well. For 16 bytes (default) alignment, 448 / 16 = 28 different random positions are possible, yielding fractional randomization of 4.8 bits.