Attachment 85788 Details for Bug 60340 – [3/6] _dbus_read_credentials_socket: document where we use each mechanism

[patch] [3/6] _dbus_read_credentials_socket: document where we use each mechanism

0002-_dbus_read_credentials_socket-document-where-we-use-.patch (text/plain), 3.56 KB, created by Simon McVittie on 2013-09-13 18:26:32 UTC

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Creator: Simon McVittie

Created: 2013-09-13 18:26:32 UTC

Size: 3.56 KB

patch

obsolete

>From 94c8b2b911756b18ab516398aded750e9b169765 Mon Sep 17 00:00:00 2001
>From: Simon McVittie <simon.mcvittie@collabora.co.uk>
>Date: Fri, 13 Sep 2013 18:50:40 +0100
>Subject: [PATCH 2/5] _dbus_read_credentials_socket: document where we use each
> mechanism
>
>---
> dbus/dbus-sysdeps-unix.c | 42 +++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 41 insertions(+), 1 deletion(-)
>
>diff --git a/dbus/dbus-sysdeps-unix.c b/dbus/dbus-sysdeps-unix.c
>index a5b141c..122c04a 100644
>--- a/dbus/dbus-sysdeps-unix.c
>+++ b/dbus/dbus-sysdeps-unix.c
>@@ -1720,6 +1720,14 @@ _dbus_read_credentials_socket  (int              client_fd,
> 
>   {
> #ifdef SO_PEERCRED
>+    /* Supported by at least Linux and OpenBSD, with minor differences.
>+     *
>+     * This mechanism passes the process ID through and does not require
>+     * the peer's cooperation, so we prefer it over all others. Notably,
>+     * Linux also supports SCM_CREDENTIALS, which is similar to FreeBSD
>+     * SCM_CREDS; it's implemented in GIO, but we don't use it in dbus at all,
>+     * because this is much less fragile.
>+     */
> #ifdef __OpenBSD__
>     struct sockpeercred cr;
> #else
>@@ -1739,12 +1747,41 @@ _dbus_read_credentials_socket  (int              client_fd,
> 		       cr_len, (int) sizeof (cr), _dbus_strerror (errno));
>       }
> #elif defined(HAVE_CMSGCRED)
>+    /* We only check for HAVE_CMSGCRED, but we're really assuming that the
>+     * presence of that struct implies SCM_CREDS. Supported by at least
>+     * FreeBSD and DragonflyBSD.
>+     *
>+     * This mechanism requires the peer to help us (it has to send us a
>+     * SCM_CREDS message) but it does pass the process ID through,
>+     * which makes it better than getpeereid().
>+     */
>     struct cmsgcred *cred;
> 
>     cred = (struct cmsgcred *) CMSG_DATA (&cmsg.hdr);
>     pid_read = cred->cmcred_pid;
>     uid_read = cred->cmcred_euid;
>+
>+    /* ----------------------------------------------------------------
>+     * When adding new mechanisms, please add them above this point
>+     * if they support passing the process ID through, or below if not.
>+     * ---------------------------------------------------------------- */
>+
> #elif defined(HAVE_GETPEEREID)
>+    /* getpeereid() originates from D.J. Bernstein and is fairly
>+     * widely-supported. According to a web search, it might be present in
>+     * any/all of:
>+     *
>+     * - AIX?
>+     * - Blackberry?
>+     * - Cygwin
>+     * - FreeBSD 4.6+ (but we prefer SCM_CREDS: it carries the pid)
>+     * - Mac OS X
>+     * - Minix 3.1.8+
>+     * - MirBSD?
>+     * - NetBSD 5.0+ (but LOCAL_PEEREID would be better: it carries the pid)
>+     * - OpenBSD 3.0+ (but we prefer SO_PEERCRED: it carries the pid)
>+     * - QNX?
>+     */
>     uid_t euid;
>     gid_t egid;
>     if (getpeereid (client_fd, &euid, &egid) == 0)
>@@ -1756,6 +1793,9 @@ _dbus_read_credentials_socket  (int              client_fd,
>         _dbus_verbose ("Failed to getpeereid() credentials: %s\n", _dbus_strerror (errno));
>       }
> #elif defined(HAVE_GETPEERUCRED)
>+    /* Supported in at least Solaris >= 10. It should probably be higher
>+     * up this list, because it carries the pid and we use this code path
>+     * for audit data. */
>     ucred_t * ucred = NULL;
>     if (getpeerucred (client_fd, &ucred) == 0)
>       {
>@@ -1799,7 +1839,7 @@ _dbus_read_credentials_socket  (int              client_fd,
>       }
>     if (ucred != NULL)
>       ucred_free (ucred);
>-#else /* !SO_PEERCRED && !HAVE_CMSGCRED && !HAVE_GETPEEREID && !HAVE_GETPEERUCRED */
>+#else /* no supported mechanism */
>     _dbus_verbose ("Socket credentials not supported on this OS\n");
> #endif
>   }
>-- 
>1.8.4.rc3
>

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Attachments on bug 60340: 74261 | 74677 | 74679 | 74680 | 74698 | 75145 | 85786 | 85787 | 85788 | 85789 | 85790 | 85791

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