perf probe: Ensure offset provided is not greater than function length

The perf probe command allows kprobe to be inserted at any offset from a
function start, which results in adding kprobes to unintended location.

Example: perf probe do_fork+10000 is allowed even though size of do_fork
is ~904.

This patch will ensure probe addition fails when the offset specified is
greater than size of the function.

Acked-by: Masami Hiramatsu <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Prashanth Nageshappa <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/util/probe-finder.c

@@ -672,7 +672,7 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
 				  bool retprobe, struct probe_trace_point *tp)
 {
-	Dwarf_Addr eaddr;
+	Dwarf_Addr eaddr, highaddr;
 	const char *name;
 
 	/* Copy the name of probe point */
@@ -683,6 +683,16 @@ static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
 				   dwarf_diename(sp_die));
 			return -ENOENT;
 		}
+		if (dwarf_highpc(sp_die, &highaddr) != 0) {
+			pr_warning("Failed to get end address of %s\n",
+				   dwarf_diename(sp_die));
+			return -ENOENT;
+		}
+		if (paddr > highaddr) {
+			pr_warning("Offset specified is greater than size of %s\n",
+				   dwarf_diename(sp_die));
+			return -EINVAL;
+		}
 		tp->symbol = strdup(name);
 		if (tp->symbol == NULL)
 			return -ENOMEM;