memory exhausted in chmd_read_headers()

[kyz]

memory exhausted in chmd_read_headers()

[kyz]

Thanks for reporting this.

As per issue #25, this is not a security issue. It's up to code controlling libmspack to set hard memory usage limits, if such limits are desired. Use a custom mspack_system.alloc() function to return NULL to libmspack if it goes over your arbitrary memory limit, instead of allocating the memory. libmspack will follow through and return MSPACK_ERR_NOMEMORY to the client.

However, I agree with adding another validation here, to reject bad CHM files. chmhs1_ChunkSize commonly only ever has one value, 4096. All files created with hhc.exe have this value. I have a single file with a larger chunk size (8192) and it was created by someone developing a competing CHM file creator, which they've since abandoned.

I've set an upper limit of 8192 for this field in commit 3b106e2.

If anyone has valid CHM files where this field is larger, please write to me.