RE: [PATCH v2 1/5] kprobes: convert kprobe_lookup_name() to a function

[David Laight]

From: Naveen N. Rao
> Sent: 12 April 2017 11:58
...
> +kprobe_opcode_t *kprobe_lookup_name(const char *name)
> +{
...
> +	char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];
> +	const char *modsym;
> +	bool dot_appended = false;
> +	if ((modsym = strchr(name, ':')) != NULL) {
> +		modsym++;
> +		if (*modsym != '\0' && *modsym != '.') {
> +			/* Convert to <module:.symbol> */
> +			strncpy(dot_name, name, modsym - name);
> +			dot_name[modsym - name] = '.';
> +			dot_name[modsym - name + 1] = '\0';
> +			strncat(dot_name, modsym,
> +				sizeof(dot_name) - (modsym - name) - 2);
> +			dot_appended = true;

If the ':' is 'a way down' name[] then although the strncpy() won't
overrun dot_name[] the rest of the code can.

The strncat() call is particularly borked.

	David