MINOR: cli/debug: validate addresses using may_access() in "debug dev stream"

This function adds some control by verifying that the target address is
really readable. It will not protect against writing to wrong places,
but will at least protect against a large number of mistakes such as
incorrectly copy-pasted addresses.

diff --git a/src/debug.c b/src/debug.c
index f9acdbff10331dbee8741c7ba6597a167d4a318d..ebb95c7e064470baf19c9d045e3086fa4b6f3a6c 100644 (file)
--- a/src/debug.c
+++ b/src/debug.c
@@ -460,14 +460,14 @@ static int debug_parse_cli_stream(char **args, char *payload, struct appctx *app
                } else if (isteq(name, ist("sib.s"))) {
                        ptr = &s->si[1].state; size = sizeof(s->si[1].state);
                } else if (isteq(name, ist("wake"))) {
-                       if (s)
+                       if (s && may_access(s) && may_access((void *)s + sizeof(*s) - 1))
                                task_wakeup(s->task, TASK_WOKEN_TIMER|TASK_WOKEN_IO|TASK_WOKEN_MSG);
                        continue;
                } else
                        return cli_dynerr(appctx, memprintf(&msg, "Unsupported field name: '%s'.\n", word));
 
                /* read previous value */
-               if (s && ptr) {
+               if ((s || ptr == &s) && ptr && may_access(ptr) && may_access(ptr + size - 1)) {
                        if (size == 8)
                                old = read_u64(ptr);
                        else if (size == 4)
@@ -476,6 +476,11 @@ static int debug_parse_cli_stream(char **args, char *payload, struct appctx *app
                                old = read_u16(ptr);
                        else
                                old = *(const uint8_t *)ptr;
+               } else {
+                       memprintf(&msg,
+                                 "%sSkipping inaccessible pointer %p for field '%.*s'.\n",
+                                 msg ? msg : "", ptr, (int)(end - word), word);
+                       continue;
                }
 
                /* parse the new value . */
@@ -517,7 +522,7 @@ static int debug_parse_cli_stream(char **args, char *payload, struct appctx *app
                }
 
                /* write the new value */
-               if (s && ptr && new != old) {
+               if (new != old) {
                        if (size == 8)
                                write_u64(ptr, new);
                        else if (size == 4)