1 files changed, 91 insertions, 0 deletions
diff --git a/debian/patches/drop-privs-after-opening-savefile.diff b/debian/patches/drop-privs-after-opening-savefile.diff
new file mode 100644
index 0000000..4eecc6c
--- /dev/null
+++ b/debian/patches/drop-privs-after-opening-savefile.diff
@@ -0,0 +1,91 @@
+Description: Drop root privileges after opening savefile
+Forwarded: no
+Bug-Debian: https://bugs.debian.org/935112
+Origin: https://src.fedoraproject.org/rpms/tcpdump/raw/master/f/0003-Drop-root-priviledges-before-opening-first-savefile-.patch
+---
+ tcpdump.1.in |  7 ++++++-
+ tcpdump.c    | 30 ++++++++++++++++++++++++++++++
+ 2 files changed, 36 insertions(+), 1 deletion(-)
+
+--- a/tcpdump.1.in
++++ b/tcpdump.1.in
+@@ -269,6 +269,9 @@
+ 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
+@@ -966,12 +969,14 @@
+ If
+ .I tcpdump
+ is running as root, after opening the capture device or input savefile,
+-but before opening any savefiles for output, change the user ID to
++change the user ID to
+ .I user
+ 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.
+--- a/tcpdump.c
++++ b/tcpdump.c
+@@ -1492,6 +1492,7 @@
+ 	cap_rights_t rights;
+ 	int cansandbox;
+ #endif	/* HAVE_CAPSICUM */
++	int chown_flag = 0;
+ 	int Oflag = 1;			/* run filter code optimizer */
+ 	int yflag_dlt = -1;
+ 	const char *yflag_dlt_name = NULL;
+@@ -2320,6 +2321,19 @@
+ 		}
+ 		capng_apply(CAPNG_SELECT_BOTH);
+ #endif /* HAVE_LIBCAP_NG */
++	/* 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.
++	 */
++	if (WFileName)
++		if (Cflag && (username || chroot_dir))
++			droproot(username, chroot_dir);
++		else
++			chown_flag = 1;
++	else
+ 		if (username || chroot_dir)
+ 			droproot(username, chroot_dir);
+ 
+@@ -2377,6 +2391,22 @@
+ #endif /* HAVE_LIBCAP_NG */
+ 		if (pdd == NULL)
+ 			error("%s", pcap_geterr(pd));
++
++		/* 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 (strcmp(WFileName, "-") && 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_CAPSICUM
+ 		set_dumper_capsicum_rights(pdd);
+ #endif