tcpdump/tcpdump-4.4.0-eperm.patch
2013-06-06 17:42:48 +02:00

78 lines
2.7 KiB
Diff

diff -up tcpdump-4.4.0/tcpdump.1.in.eperm tcpdump-4.4.0/tcpdump.1.in
--- tcpdump-4.4.0/tcpdump.1.in.eperm 2013-05-06 13:24:27.832436506 +0200
+++ tcpdump-4.4.0/tcpdump.1.in 2013-05-06 13:24:27.839436511 +0200
@@ -221,6 +221,9 @@ have the name specified with the
flag, with a number after it, starting at 1 and continuing upward.
The units of \fIfile_size\fP are millions of bytes (1,000,000 bytes,
not 1,048,576 bytes).
+
+Note that when used with \fB\-Z\fR option (enabled by default), privileges
+are dropped before opening first savefile.
.TP
.B \-d
Dump the compiled packet-matching code in a human readable form to
@@ -720,7 +723,9 @@ but before opening any savefiles for out
and the group ID to the primary group of
.IR user .
.IP
-This behavior can also be enabled by default at compile time.
+This behavior is enabled by default (\fB\-Z tcpdump\fR), and can
+be disabled by \fB\-Z root\fR.
+
.IP "\fI expression\fP"
.RS
selects which packets will be dumped.
diff -up tcpdump-4.4.0/tcpdump.c.eperm tcpdump-4.4.0/tcpdump.c
--- tcpdump-4.4.0/tcpdump.c.eperm 2013-03-24 22:49:18.000000000 +0100
+++ tcpdump-4.4.0/tcpdump.c 2013-05-06 13:28:40.929602618 +0200
@@ -1426,11 +1426,24 @@ main(int argc, char **argv)
}
#endif /* HAVE_CAP_NG_H */
- if (getuid() == 0 || geteuid() == 0) {
- if (username || chroot_dir)
+ /* If user is running tcpdump as root and wants to write to the savefile,
+ * we will check if -C is set and if it is, we will drop root
+ * privileges right away and consequent call to pcap_dump_open()
+ * will most likely fail for the first file. If -C flag is not set we
+ * will create file as root then change ownership of file to proper
+ * user(default tcpdump) and drop root privileges.
+ */
+ int chown_flag = 0;
+
+ if (WFileName && (getuid() == 0 || geteuid() == 0))
+ if (Cflag && (username || chroot_dir))
+ droproot(username, chroot_dir);
+ else
+ chown_flag = 1;
+ else
+ if ((getuid() == 0 || geteuid() == 0) && (username || chroot_dir))
droproot(username, chroot_dir);
- }
#endif /* WIN32 */
if (pcap_setfilter(pd, &fcode) < 0)
@@ -1450,6 +1463,21 @@ main(int argc, char **argv)
MakeFilename(dumpinfo.CurrentFileName, WFileName, 0, 0);
p = pcap_dump_open(pd, dumpinfo.CurrentFileName);
+
+ /* Change ownership of file and drop root privileges */
+ if (chown_flag) {
+ struct passwd *pwd;
+
+ pwd = getpwnam(username);
+ if (!pwd)
+ error("Couldn't find user '%s'", username);
+
+ if (chown(dumpinfo.CurrentFileName, pwd->pw_uid, pwd->pw_gid) < 0)
+ error("Couldn't change ownership of savefile");
+
+ if (username || chroot_dir)
+ droproot(username, chroot_dir);
+ }
#ifdef HAVE_CAP_NG_H
/* Give up capabilities, clear Effective set */
capng_clear(CAPNG_EFFECTIVE);