[SCM] GNU Inetutils branch, master, updated. inetutils-1_9_4-23-g7267896

[Mats Erik Andersson]

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- Log -----------------------------------------------------------------
http://git.savannah.gnu.org/cgit/inetutils.git/commit/?id=7267896f92e3df2eb935b5b8dd4adde1ee0b4c21


commit 7267896f92e3df2eb935b5b8dd4adde1ee0b4c21
Author: Mats Erik Andersson <address@hidden>
Date:   Tue Feb 16 23:29:25 2016 +0100

    traceroute: Subprivileged use case.
    
    A fallback for ICMP tracing relevant to GNU/Linux is implemented,
    allowing a rudimentary but suid-less use case.

diff --git a/ChangeLog b/ChangeLog
index 3c42992..b85e63d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+2016-02-16  Mats Erik Andersson  <address@hidden>
+
+       traceroute: Subprivileged use case.
+       A fallback for ICMP tracing relevant to GNU/Linux is implemented,
+       allowing a rudimentary but suid-less use case.  The ability to
+       identify intermediary hosts is missing, due to the crippled
+       capability of receiving ICMP packets other than ICMP_ECHOREPLY.
+
+       * src/traceroute.c (struct trace): New member `no_ident'.
+       (trace_init): Initiate `t->no_ident'.
+       <type TRACE_ICMP or TRACE_UDP>: In case a raw socket for an ICMP
+       protocol fails, fall back to a datagram socket.
+       (trace_read) <type TRACE_ICMP>: Short circuit `ic->icmp_id != pid'
+       with the conditional `t->no_ident == 0'.
+       (trace_write) <type TRACE_ICMP>: New variable I.  Initialize HDR
+       to its full extent.  If `t->no_ident' is non-zero, insert our
+       intended target as payload of HDR for trace identification.
+
 2016-02-12  Mats Erik Andersson  <address@hidden>
 
        ping: Implement subprivileged echo method.
diff --git a/src/traceroute.c b/src/traceroute.c
index dac45e7..301507d 100644
--- a/src/traceroute.c
+++ b/src/traceroute.c
@@ -75,6 +75,7 @@ typedef struct trace
 {
   int icmpfd, udpfd;
   enum trace_type type;
+  int no_ident;
   struct sockaddr_in to, from;
   int ttl;
   struct timeval tsent;
@@ -476,6 +477,7 @@ trace_init (trace_t * t, const struct sockaddr_in to,
   t->type = type;
   t->to = to;
   t->ttl = opt_ttl;
+  t->no_ident = 0;
 
   if (t->type == TRACE_UDP)
     {
@@ -494,6 +496,21 @@ trace_init (trace_t * t, const struct sockaddr_in to,
       if (protocol)
        {
          t->icmpfd = socket (PF_INET, SOCK_RAW, protocol->p_proto);
+         if (t->icmpfd < 0 && (errno == EPERM || errno == EACCES))
+           {
+             /* A subprivileged user on GNU/Linux might be allowed
+              * to create ICMP packets from a datagram socket.
+              * Such packets are always severely crippled.
+              */
+             errno = 0;
+             t->icmpfd = socket (PF_INET, SOCK_DGRAM, protocol->p_proto);
+             t->no_ident++;
+
+             /* Recover error message for non-Linux systems.  */
+             if (errno == EPROTONOSUPPORT)
+               errno = EPERM;
+           }
+
          if (t->icmpfd < 0)
            error (EXIT_FAILURE, errno, "socket");
 
@@ -609,7 +626,7 @@ trace_read (trace_t * t, int * type, int * code)
 
       if (ic->icmp_type == ICMP_ECHOREPLY
          && (ntohs (ic->icmp_seq) != seqno
-             || ntohs (ic->icmp_id) != pid))
+             || (ntohs (ic->icmp_id) != pid && t->no_ident == 0)))
        return -1;
 
       if (ic->icmp_type == ICMP_TIME_EXCEEDED
@@ -685,6 +702,17 @@ trace_write (trace_t * t)
     case TRACE_ICMP:
       {
        icmphdr_t hdr;
+       int i;
+
+       /* Deposit deterministic values throughout the header!  */
+       for (i = 0; i < sizeof (hdr); ++i)
+         *((char *) &hdr + i) = i;
+
+       /* The subprivileged use case of ICMP sent over datagram
+        * sockets needs extra help with identification of target.
+        */
+       if (t->no_ident)
+         *((int *) &hdr + 12 / sizeof(int)) = dest.sin_addr.s_addr;
 
        /* The sequence number is updated to a valid value!  */
        if (icmp_echo_encode ((unsigned char *) &hdr, sizeof (hdr),

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog        |   18 ++++++++++++++++++
 src/traceroute.c |   30 +++++++++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 1 deletions(-)


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