fakeidentd: fix use-after-free

function                                             old     new   delta
do_rd                                                199     197      -2

Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 12 insertions, 13 deletions

diff --git a/networking/isrv_identd.c b/networking/isrv_identd.c
index a41405c33..c6b0f6528 100644
--- a/networking/isrv_identd.c
+++ b/networking/isrv_identd.c
@@ -51,19 +51,18 @@ static int do_rd(int fd, void **paramp)
 {
         identd_buf_t *buf = *paramp;
         char *cur, *p;
-        int retval = 0; /* session is ok (so far) */
         int sz;
 
         cur = buf->buf + buf->pos;
 
         if (buf->fd_flag & O_NONBLOCK)
                 fcntl(fd, F_SETFL, buf->fd_flag);
-        sz = safe_read(fd, cur, sizeof(buf->buf) - buf->pos);
+        sz = safe_read(fd, cur, sizeof(buf->buf) - 1 - buf->pos);
 
         if (sz < 0) {
                 if (errno != EAGAIN)
-                        goto term; /* terminate this session if !EAGAIN */
-                goto ok;
+                        goto term;
+                return 0; /* "session is ok" */
         }
 
         buf->pos += sz;
@@ -71,19 +70,19 @@ static int do_rd(int fd, void **paramp)
         p = strpbrk(cur, "\r\n");
         if (p)
                 *p = '\0';
-        if (!p && sz && buf->pos <= (int)sizeof(buf->buf))
-                goto ok;
+        if (!p && sz && buf->pos < (int)sizeof(buf->buf))
+                return 0;  /* "session is ok" */
+
         /* Terminate session. If we are in server mode, then
          * fd is still in nonblocking mode - we never block here */
-        if (fd == 0) fd++; /* inetd mode? then write to fd 1 */
+        if (fd == 0)
+                fd++; /* inetd mode? then write to fd 1 */
         fdprintf(fd, "%s : USERID : UNIX : %s\r\n", buf->buf, bogouser);
- term:
-        free(buf);
-        retval = 1; /* terminate */
- ok:
         if (buf->fd_flag & O_NONBLOCK)
                 fcntl(fd, F_SETFL, buf->fd_flag & ~O_NONBLOCK);
-        return retval;
+ term:
+        free(buf);
+        return 1; /* "terminate" */
 }
 
 static int do_timeout(void **paramp UNUSED_PARAM)
@@ -120,7 +119,7 @@ int fakeidentd_main(int argc UNUSED_PARAM, char **argv)
         opt = getopt32(argv, "fiwb:", &bind_address);
         strcpy(bogouser, "nobody");
         if (argv[optind])
-                strncpy(bogouser, argv[optind], sizeof(bogouser));
+                strncpy(bogouser, argv[optind], sizeof(bogouser) - 1);
 
         /* Daemonize if no -f and no -i and no -w */
         if (!(opt & OPT_fiw))