shithub: jbig2

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jbig2dec: Avoid passing NULL buffer to snprintf().

--- a/jbig2dec.c

+++ b/jbig2dec.c

@@ -376,7 +376,6 @@

 {

     jbig2dec_error_callback_state_t *state = (jbig2dec_error_callback_state_t *) error_callback_data;

     char *type;

-    char segment[22];

     int len;

     char *message;

@@ -403,27 +402,25 @@

         type = "unknown message";

         break;

     }

-    if (seg_idx == -1)

-        segment[0] = '\0';

-    else

-        snprintf(segment, sizeof(segment), "(segment 0x%02x)", seg_idx);

-    len = snprintf(NULL, 0, "jbig2dec %s %s %s", type, buf, segment);

-    if (len < 0) {

-        return;

-    }

+    /* Worst case length using format "jbig2dec %s %s (segment 0x%02x)".

+    strlen("jbig2dec ") +

+    strlen(type) + strlen(" ") +

+    strlen(buf) + strlen(" ") +

+    strlen("(segment 0x") + strlen("2147483648") + strlen(")") +

+    1 for trailing NUL. The constant parts amount to 45 bytes. */

+    len = 45;

+    len += strlen(type);

+    len += strlen(buf);

     message = malloc(len + 1);

     if (message == NULL) {

         return;

     }

-

-    len = snprintf(message, len + 1, "jbig2dec %s %s %s", type, buf, segment);

-    if (len < 0)

-    {

-        free(message);

-        return;

-    }

+    if (seg_idx == -1)

+        snprintf(message, len + 1, "jbig2dec %s %s", type, buf);

+    else

+        snprintf(message, len + 1, "jbig2dec %s %s (segment 0x%02x)", type, buf, seg_idx);

     if (state->last_message != NULL && strcmp(message, state->last_message)) {

         if (state->repeats > 1)