Revamp SSH authentication code so that user interaction is more

[u/mdw/putty] / misc.c

diff --git a/misc.c b/misc.c
index 474bf02..37ac0a1 100644 (file)
--- a/misc.c
+++ b/misc.c
@@ -5,10 +5,128 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <limits.h>
 #include <ctype.h>
 #include <assert.h>
 #include "putty.h"
 
+/*
+ * Parse a string block size specification. This is approximately a
+ * subset of the block size specs supported by GNU fileutils:
+ *  "nk" = n kilobytes
+ *  "nM" = n megabytes
+ *  "nG" = n gigabytes
+ * All numbers are decimal, and suffixes refer to powers of two.
+ * Case-insensitive.
+ */
+unsigned long parse_blocksize(const char *bs)
+{
+    char *suf;
+    unsigned long r = strtoul(bs, &suf, 10);
+    if (*suf != '\0') {
+       while (*suf && isspace((unsigned char)*suf)) suf++;
+       switch (*suf) {
+         case 'k': case 'K':
+           r *= 1024ul;
+           break;
+         case 'm': case 'M':
+           r *= 1024ul * 1024ul;
+           break;
+         case 'g': case 'G':
+           r *= 1024ul * 1024ul * 1024ul;
+           break;
+         case '\0':
+         default:
+           break;
+       }
+    }
+    return r;
+}
+
+/*
+ * Parse a ^C style character specification.
+ * Returns NULL in `next' if we didn't recognise it as a control character,
+ * in which case `c' should be ignored.
+ * The precise current parsing is an oddity inherited from the terminal
+ * answerback-string parsing code. All sequences start with ^; all except
+ * ^<123> are two characters. The ones that are worth keeping are probably:
+ *   ^?                    127
+ *   ^@A-Z[\]^_            0-31
+ *   a-z           1-26
+ *   <num>         specified by number (decimal, 0octal, 0xHEX)
+ *   ~             ^ escape
+ */
+char ctrlparse(char *s, char **next)
+{
+    char c = 0;
+    if (*s != '^') {
+       *next = NULL;
+    } else {
+       s++;
+       if (*s == '\0') {
+           *next = NULL;
+       } else if (*s == '<') {
+           s++;
+           c = (char)strtol(s, next, 0);
+           if ((*next == s) || (**next != '>')) {
+               c = 0;
+               *next = NULL;
+           } else
+               (*next)++;
+       } else if (*s >= 'a' && *s <= 'z') {
+           c = (*s - ('a' - 1));
+           *next = s+1;
+       } else if ((*s >= '@' && *s <= '_') || *s == '?' || (*s & 0x80)) {
+           c = ('@' ^ *s);
+           *next = s+1;
+       } else if (*s == '~') {
+           c = '^';
+           *next = s+1;
+       }
+    }
+    return c;
+}
+
+prompts_t *new_prompts(void *frontend)
+{
+    prompts_t *p = snew(prompts_t);
+    p->prompts = NULL;
+    p->n_prompts = 0;
+    p->frontend = frontend;
+    p->data = NULL;
+    p->to_server = TRUE; /* to be on the safe side */
+    p->name = p->instruction = NULL;
+    p->name_reqd = p->instr_reqd = FALSE;
+    return p;
+}
+void add_prompt(prompts_t *p, char *promptstr, int echo, size_t len)
+{
+    prompt_t *pr = snew(prompt_t);
+    unsigned char *result = snewn(len, unsigned char);
+    pr->prompt = promptstr;
+    pr->echo = echo;
+    pr->result = result;
+    pr->result_len = len;
+    p->n_prompts++;
+    p->prompts = sresize(p->prompts, p->n_prompts, prompt_t *);
+    p->prompts[p->n_prompts-1] = pr;
+}
+void free_prompts(prompts_t *p)
+{
+    size_t i;
+    for (i=0; i < p->n_prompts; i++) {
+       prompt_t *pr = p->prompts[i];
+       memset(pr->result, 0, pr->result_len); /* burn the evidence */
+       sfree(pr->result);
+       sfree(pr->prompt);
+       sfree(pr);
+    }
+    sfree(p->prompts);
+    sfree(p->name);
+    sfree(p->instruction);
+    sfree(p);
+}
+
 /* ----------------------------------------------------------------------
  * String handling routines.
  */
@@ -355,14 +473,22 @@ void mlog(char *file, int line)
 }
 #endif
 
-void *safemalloc(size_t size)
+void *safemalloc(size_t n, size_t size)
 {
     void *p;
+
+    if (n > INT_MAX / size) {
+       p = NULL;
+    } else {
+       size *= n;
+       if (size == 0) size = 1;
 #ifdef MINEFIELD
-    p = minefield_c_malloc(size);
+       p = minefield_c_malloc(size);
 #else
-    p = malloc(size);
+       p = malloc(size);
 #endif
+    }
+
     if (!p) {
        char str[200];
 #ifdef MALLOC_LOG
@@ -382,22 +508,29 @@ void *safemalloc(size_t size)
     return p;
 }
 
-void *saferealloc(void *ptr, size_t size)
+void *saferealloc(void *ptr, size_t n, size_t size)
 {
     void *p;
-    if (!ptr) {
+
+    if (n > INT_MAX / size) {
+       p = NULL;
+    } else {
+       size *= n;
+       if (!ptr) {
 #ifdef MINEFIELD
-       p = minefield_c_malloc(size);
+           p = minefield_c_malloc(size);
 #else
-       p = malloc(size);
+           p = malloc(size);
 #endif
-    } else {
+       } else {
 #ifdef MINEFIELD
-       p = minefield_c_realloc(ptr, size);
+           p = minefield_c_realloc(ptr, size);
 #else
-       p = realloc(ptr, size);
+           p = realloc(ptr, size);
 #endif
+       }
     }
+
     if (!p) {
        char str[200];
 #ifdef MALLOC_LOG