cleanname has a 1-char OOB write when input is ""

[noncombatant]

It's at line 50:

plan9port/src/lib9/cleanname.c

Line 50 in 61e362a

*q = '\0';

. There isn't necessarily a second byte to write into. Detected with ASAN.

Unfortunately, I think this means the API has to change (to explicitly ignore or reject blank strings): blank strings can't be cleaned to ".".

[krstlmnn]

From cleanname(3):

The shortest string cleanname can return is two bytes: the null-terminated string ".". Therefore filename must contain room for at least two bytes.

So probably just check if name is nil or name[0] is '\0' at the start and return nil if so.

plan9port/src/lib9/cleanname.c

Line 14 in 61e362a

rooted = name[0] == '/';