strcpy of two char

[mhoemmen]

There are a few parts of the SVD function that do strcpy(&dst, &src), where each of dst and src is a char. For example:

raft/cpp/include/raft/linalg/detail/svd.cuh

Line 71 in 1dd2feb

strcpy(&jobu, &new_u);

This is incorrect for several reasons.

1. strcpy will attempt to read past the bounds of src in order to look for a null terminator (\0 character). Just doing that is UB.
2. If strcpy is lucky enough to find a null terminator, it will write both src and the null terminator (thus, two characters) to &dst. This is UB because dst only points to one character. It could clobber something on the stack (maybe even src).
3. There's no guarantee that the next character after src is a null terminator. This means strcpy could clobber arbitrarily many bytes on the stack with random other bytes on the stack.