Subject: [bug#41874] [PATCH] gnu: wireshark: Lookup 'dumpcap' in PATH.

From: Brice Waegeneire <[email-masked]>
Date: Mon, 15 Jun 2020 18:18:41 +0200

* gnu/packages/patches/wireshark-lookup-dumpcap-in-path.patch: New file
…
* gnu/local.mk: … add it …
* gnu/packages/networking.scm (wireshark)[origin]: … use it.
---

Together with https://issues.guix.info/41763 this patch allow to use wireshark
as a non-root user be adding the following to your “oeprating-system-services“
field:

--8<---------------cut here---------------start------------->8---
(simple-service 'wireshark-group account-service-type
                   (list (user-group (name "wireshark") (system? #t))))
(simple-service 'wireshark-dumpcap setuid-program-service-type
                   (list (list (file-append wireshark "/bin/dumpcap")
                               "root" "wireshark")))
--8<---------------cut here---------------end--------------->8---

Such feature was asked on the mailing list years ago[0].

[0]: https://lists.gnu.org/archive/html/help-guix/2016-11/msg00043.html

 gnu/local.mk                                  |  1 +
 gnu/packages/networking.scm                   |  1 +
 .../wireshark-lookup-dumpcap-in-path.patch    | 66 +++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 gnu/packages/patches/wireshark-lookup-dumpcap-in-path.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 79bdfe9be8..3b07aa248c 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1595,6 +1595,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/wicd-get-selected-profile-fix.patch	\
   %D%/packages/patches/wicd-urwid-1.3.patch			\
   %D%/packages/patches/wicd-wpa2-ttls.patch			\
+  %D%/packages/patches/wireshark-lookup-dumpcap-in-path.patch	\
   %D%/packages/patches/wmctrl-64-fix.patch			\
   %D%/packages/patches/wmfire-update-for-new-gdk-versions.patch	\
   %D%/packages/patches/wordnet-CVE-2008-2149.patch			\
diff --git a/gnu/packages/networking.scm b/gnu/packages/networking.scm
index e8f398e521..216e5072a4 100644
--- a/gnu/packages/networking.scm
+++ b/gnu/packages/networking.scm
@@ -873,6 +873,7 @@ of the same name.")
        (method url-fetch)
        (uri (string-append "https://www.wireshark.org/download/src/wireshark-"
                            version ".tar.xz"))
+       (patches (search-patches "wireshark-lookup-dumpcap-in-path.patch"))
        (sha256
         (base32 "1amqgn94g6h6cfnsccm2zb4c73pfv1qmzi1i6h1hnbcyhhg4czfi"))))
     (build-system cmake-build-system)
diff --git a/gnu/packages/patches/wireshark-lookup-dumpcap-in-path.patch b/gnu/packages/patches/wireshark-lookup-dumpcap-in-path.patch
new file mode 100644
index 0000000000..4c000c23a1
--- /dev/null
+++ b/gnu/packages/patches/wireshark-lookup-dumpcap-in-path.patch
@@ -0,0 +1,66 @@
+Taken from Nixpkgs:
+<https://github.com/NixOS/nixpkgs/blob/aa060ababf1490e8b39a6122d42112ea958f39cf/pkgs/applications/networking/sniffers/wireshark/wireshark-lookup-dumpcap-in-path.patch>
+
+From 5bef9deeff8a2e4401de0f45c9701cd6f98f29d8 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Bj=C3=B8rn=20Forsman?= <[email-masked]>
+Date: Thu, 26 Nov 2015 21:03:35 +0100
+Subject: [PATCH] Lookup dumpcap in PATH
+
+NixOS patch: Look for dumpcap in PATH first, because there may be a
+dumpcap wrapper that we want to use instead of the default
+non-setuid dumpcap binary.
+
+Also change execv() to execvp() because we've set argv[0] to "dumpcap"
+and have to enable PATH lookup. Wireshark is not a setuid program, so
+looking in PATH is not a security issue.
+
+Signed-off-by: Franz Pletz <[email-masked]>
+---
+ capchild/capture_sync.c | 17 ++++++++++++++---
+ 1 file changed, 14 insertions(+), 3 deletions(-)
+
+diff --git a/capchild/capture_sync.c b/capchild/capture_sync.c
+index 970688e..49914d5 100644
+--- a/capchild/capture_sync.c
++++ b/capchild/capture_sync.c
+@@ -332,7 +332,18 @@ init_pipe_args(int *argc) {
+ #ifdef _WIN32
+     exename = g_strdup_printf("%s\\dumpcap.exe", progfile_dir);
+ #else
+-    exename = g_strdup_printf("%s/dumpcap", progfile_dir);
++    /*
++     * NixOS patch: Look for dumpcap in PATH first, because there may be a
++     * dumpcap wrapper that we want to use instead of the default
++     * non-setuid dumpcap binary.
++     */
++    if (system("command -v dumpcap >/dev/null") == 0) {
++        /* Found working dumpcap */
++        exename = g_strdup_printf("dumpcap");
++    } else {
++        /* take Wireshark's absolute program path and replace "Wireshark" with "dumpcap" */
++        exename = g_strdup_printf("%s/dumpcap", progfile_dir);
++    }
+ #endif
+ 
+     /* Make that the first argument in the argument list (argv[0]). */
+@@ -729,7 +740,7 @@ sync_pipe_start(capture_options *capture_opts, capture_session *cap_session, voi
+          */
+         dup2(sync_pipe[PIPE_WRITE], 2);
+         ws_close(sync_pipe[PIPE_READ]);
+-        execv(argv[0], argv);
++        execvp(argv[0], argv);
+         g_snprintf(errmsg, sizeof errmsg, "Couldn't run %s in child process: %s",
+                    argv[0], g_strerror(errno));
+         sync_pipe_errmsg_to_parent(2, errmsg, "");
+@@ -997,7 +1008,7 @@ sync_pipe_open_command(char** argv, int *data_read_fd,
+         dup2(sync_pipe[PIPE_WRITE], 2);
+         ws_close(sync_pipe[PIPE_READ]);
+         ws_close(sync_pipe[PIPE_WRITE]);
+-        execv(argv[0], argv);
++        execvp(argv[0], argv);
+         g_snprintf(errmsg, sizeof errmsg, "Couldn't run %s in child process: %s",
+                    argv[0], g_strerror(errno));
+         sync_pipe_errmsg_to_parent(2, errmsg, "");
+-- 
+2.6.3
+
-- 
2.26.2