75cba9c67fde03421b96c1bcbaf666b4b348739d
when a null buffer pointer is passed to fmemopen, requesting it allocate its own memory buffer, extremely large size arguments near SIZE_MAX could overflow and result in underallocation. this results from omission of the size of the cookie structure in the overflow check but inclusion of it in the calloc call. instead of accounting for individual small contributions to the total allocation size needed, simply reject sizes larger than PTRDIFF_MAX, which will necessarily fail anyway. then adding arbitrary fixed-size structures is safe without matching up the expressions in the comparison and the allocation.
musl libc
musl, pronounced like the word "mussel", is an MIT-licensed
implementation of the standard C library targetting the Linux syscall
API, suitable for use in a wide range of deployment environments. musl
offers efficient static and dynamic linking support, lightweight code
and low runtime overhead, strong fail-safe guarantees under correct
usage, and correctness in the sense of standards conformance and
safety. musl is built on the principle that these goals are best
achieved through simple code that is easy to understand and maintain.
The 1.1 release series for musl features coverage for all interfaces
defined in ISO C99 and POSIX 2008 base, along with a number of
non-standardized interfaces for compatibility with Linux, BSD, and
glibc functionality.
For basic installation instructions, see the included INSTALL file.
Information on full musl-targeted compiler toolchains, system
bootstrapping, and Linux distributions built on musl can be found on
the project website:
http://www.musl-libc.org/