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 <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/4F473F33.4060409@linux.vnet.ibm.com
Signed-off-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 5d732621a462f31a57d9aa966fe80e23edacf4b8..74bd2e63c4b4a7458989a08cc731c15edfb99c98 100644 (file)
--- a/tools/perf/util/probe-finder.c
+++ b/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;