vi: detect and warn about invalid line addresses

BusyBox vi didn't have proper handling for invalid markers or
unsuccessful searches in colon line addresses.  This could result
in the wrong lines being affected by a change.

Detect when an invalid address is specified, propagate an error
indicator up the call chain and issue a warning.

function                                             old     new   delta
colon                                               3604    3661     +57
.rodata                                           105195  105211     +16
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 73/0)               Total: 73 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 14 insertions, 8 deletions

diff --git a/editors/vi.c b/editors/vi.c
index 9c32ed836..1d326f454 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -2360,14 +2360,15 @@ static char *get_one_address(char *p, int *addr)	// get colon addr, if present
                 p++;
                 c = tolower(*p);
                 p++;
+                q = NULL;
                 if (c >= 'a' && c <= 'z') {
                         // we have a mark
                         c = c - 'a';
                         q = mark[(unsigned char) c];
-                        if (q != NULL) {        // is mark valid
-                                *addr = count_lines(text, q);
-                        }
                 }
+                if (q == NULL)  // is mark valid
+                        return NULL;
+                *addr = count_lines(text, q);
         }
 # endif
 # if ENABLE_FEATURE_VI_SEARCH
@@ -2383,9 +2384,9 @@ static char *get_one_address(char *p, int *addr)	// get colon addr, if present
                         p++;
                 q = char_search(next_line(dot), last_search_pattern + 1,
                                                 (FORWARD << 1) | FULL);
-                if (q != NULL) {
-                        *addr = count_lines(text, q);
-                }
+                if (q == NULL)
+                        return NULL;
+                *addr = count_lines(text, q);
         }
 # endif
         else if (*p == '$') {   // the last line in file
@@ -2422,6 +2423,8 @@ static char *get_address(char *p, int *b, int *e)	// get two colon addrs, if pre
                         state = GET_SECOND;
                 } else if (state == GET_FIRST || state == GET_SECOND) {
                         p = get_one_address(p, state == GET_FIRST ? b : e);
+                        if (p == NULL)
+                                break;
                         state |= GOT;
                 } else {
                         break;
@@ -2536,9 +2539,7 @@ static void colon(char *buf)
         char *fn, cmd[MAX_INPUT_LEN], args[MAX_INPUT_LEN];
         int i, l, li, b, e;
         int useforce;
-# if ENABLE_FEATURE_VI_SEARCH || ENABLE_FEATURE_ALLOW_EXEC
         char *orig_buf;
-# endif
 
         // :3154        // if (-e line 3154) goto it  else stay put
         // :4,33w! foo  // write a portion of buffer to file "foo"
@@ -2568,7 +2569,12 @@ static void colon(char *buf)
         fn = current_filename;
 
         // look for optional address(es)  :.  :1  :1,9   :'q,'a   :%
+        orig_buf = buf;
         buf = get_address(buf, &b, &e);
+        if (buf == NULL) {
+                status_line_bold("Bad address: %s", orig_buf);
+                goto ret;
+        }
 
 # if ENABLE_FEATURE_VI_SEARCH || ENABLE_FEATURE_ALLOW_EXEC
         // remember orig command line