my_secmalloc

Secure malloc implementation (school project from 2023)

Features

• Allocated data separated from block metadata, preventing abuse of heap overflows
• Canary protection against overflows before running any operation on a block
• Checks for double-free conditions
• Spawns a thread that checks for canary integrity every 100 ms
• Checks for memory leaks (non-freed blocks at program exit)
• "Smart" block splitting/coalescing, preventing memory fragmentation as much as possible
• Optional verbose logging to a file of every action taken by the lib

Building

Compile with make.

Possible targets:

• make all: build libmy_secmalloc.so without verbose debugging to STDERR
• make dynamic: build libmy_secmalloc.so without verbose debugging, exporting malloc-related functions for drop-in replacement of libc's functions
• make dyn_debug: like make dynamic with verbose debug messages sent to STDERR
• make static: build libmy_secmalloc.a for testing purposes
• make build_test: build test program (test/test)
• make test: build and run test program
• make clean: delete intermediate compilation files

Usage

Running programs with libmy_secmalloc.o

To run a program using this lib's functions instead of libc's, build it with make dynamic (or make dyn_debug) and load the .so with LD_PRELOAD.

You can also set the environment variable MSM_OUTPUT to log everything to a file (allocations, function calls, etc.).

LD_PRELOAD=./lib/libmy_secmalloc.so <program> [arguments...]

# For example:
LD_PRELOAD=./lib/libmy_secmalloc.so ls -lA

MSM_OUTPUT=malloc-ls.log LD_PRELOAD=./lib/libmy_secmalloc.so ls -lA

Testing

Build the test program with make static build_test (or run it directly with make static test).