In grep 2.20, grep.c contains:
ssize_t fillsize;
size_t readsize;
[...]
fillsize = safe_read (bufdesc, readbuf, readsize);
if (fillsize < 0)
fillsize = cc = 0;
bufoffset += fillsize;
fillsize = undossify_input (readbuf, fillsize);
In practice, readsize can be large on a 64-bit machine (more than
2 GB), so that the return value of safe_read(), fillsize, can also
be large since a read() is called with readsize as the 3rd argument.
But dosbuf.c has:
static int
undossify_input (char *buf, size_t buflen)
{
if (! O_BINARY)
return buflen;
[...]
meaning that the potentially large buflen (> 2 GB) is returned as an
int, whose usual size is 32 bits only, yielding an integer overflow.
undossify_input should be rewritten in such a way that some int's are
changed to size_t or ssize_t.
Note: This bug is currently not visible under Linux due to a limitation
in the kernel (breaking POSIX compliance, BTW): the read() return value
is limited to 0x7ffff000.
--
Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
