changeset 7120:874171c3c71a

Fixed handling of non-null-terminated unix sockets. At least FreeBSD, macOS, NetBSD, and OpenBSD can return unix sockets with non-null-terminated sun_path. Additionally, the address may become non-null-terminated if it does not fit into the buffer provided and was truncated (may happen on macOS, NetBSD, and Solaris, which allow unix socket addresess larger than struct sockaddr_un). As such, ngx_sock_ntop() might overread the sockaddr provided, as it used "%s" format and thus assumed null-terminated string. To fix this, the ngx_strnlen() function was introduced, and it is now used to calculate correct length of sun_path.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 04 Oct 2017 21:19:38 +0300
parents fef61d26da39
children 924b6ef942bf
files src/core/ngx_inet.c src/core/ngx_string.c src/core/ngx_string.h
diffstat 3 files changed, 21 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/src/core/ngx_inet.c
+++ b/src/core/ngx_inet.c
@@ -241,7 +241,9 @@ ngx_sock_ntop(struct sockaddr *sa, sockl
             p = ngx_snprintf(text, len, "unix:%Z");
 
         } else {
-            p = ngx_snprintf(text, len, "unix:%s%Z", saun->sun_path);
+            n = ngx_strnlen((u_char *) saun->sun_path,
+                            socklen - offsetof(struct sockaddr_un, sun_path));
+            p = ngx_snprintf(text, len, "unix:%*s%Z", n, saun->sun_path);
         }
 
         /* we do not include trailing zero in address length */
--- a/src/core/ngx_string.c
+++ b/src/core/ngx_string.c
@@ -29,6 +29,22 @@ ngx_strlow(u_char *dst, u_char *src, siz
 }
 
 
+size_t
+ngx_strnlen(u_char *p, size_t n)
+{
+    size_t  i;
+
+    for (i = 0; i < n; i++) {
+
+        if (p[i] == '\0') {
+            return i;
+        }
+    }
+
+    return n;
+}
+
+
 u_char *
 ngx_cpystrn(u_char *dst, u_char *src, size_t n)
 {
--- a/src/core/ngx_string.h
+++ b/src/core/ngx_string.h
@@ -60,6 +60,8 @@ void ngx_strlow(u_char *dst, u_char *src
 #define ngx_strstr(s1, s2)  strstr((const char *) s1, (const char *) s2)
 #define ngx_strlen(s)       strlen((const char *) s)
 
+size_t ngx_strnlen(u_char *p, size_t n);
+
 #define ngx_strchr(s1, c)   strchr((const char *) s1, (int) c)
 
 static ngx_inline u_char *