From cd795f9abc5407db7b6c1d016e3d3d7d3d6c13db Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Tue, 25 Apr 2023 19:09:55 +0900
Subject: [PATCH] udev-rules: fix negative match rule for SYMLINK and TAG

Fixes #27396.

(cherry picked from commit 2b43ab00b08a052fc0077dd20f111c474730ad52)
---
 man/udev.xml          | 15 +++++++++------
 src/udev/udev-rules.c |  4 ++--
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/man/udev.xml b/man/udev.xml
index 142f295f3e..332c7ac096 100644
--- a/man/udev.xml
+++ b/man/udev.xml
@@ -186,10 +186,10 @@
           <varlistentry>
             <term><varname>SYMLINK</varname></term>
             <listitem>
-              <para>Match the name of a symlink targeting the node. It can
-              be used once a SYMLINK key has been set in one of the preceding
-              rules. There may be multiple symlinks; only one needs to match.
-              </para>
+              <para>Match the name of a symlink targeting the node. It can be used once a SYMLINK key has
+              been set in one of the preceding rules. There may be multiple symlinks; only one needs to
+              match. If the operator is <literal>!=</literal>, the token returns true only if there is no
+              symlink matched.</para>
             </listitem>
           </varlistentry>
 
@@ -287,14 +287,17 @@
           <varlistentry>
             <term><varname>TAG</varname></term>
             <listitem>
-              <para>Match against a device tag.</para>
+              <para>Match against one of device tags. It can be used once a TAG key has been set in one of
+              the preceding rules. There may be multiple tags; only one needs to match. If the operator is
+              <literal>!=</literal>, the token returns true only if there is no tag matched.</para>
             </listitem>
           </varlistentry>
 
           <varlistentry>
             <term><varname>TAGS</varname></term>
             <listitem>
-              <para>Search the devpath upwards for a device with matching tag.</para>
+              <para>Search the devpath upwards for a device with matching tag. If the operator is
+              <literal>!=</literal>, the token returns true only if there is no tag matched.</para>
             </listitem>
           </varlistentry>
 
diff --git a/src/udev/udev-rules.c b/src/udev/udev-rules.c
index c5244d41ac..6d33a2b061 100644
--- a/src/udev/udev-rules.c
+++ b/src/udev/udev-rules.c
@@ -1607,7 +1607,7 @@ static int udev_rule_apply_token_to_event(
                 const char *val;
 
                 FOREACH_DEVICE_DEVLINK(dev, val)
-                        if (token_match_string(token, strempty(startswith(val, "/dev/"))))
+                        if (token_match_string(token, strempty(startswith(val, "/dev/"))) == (token->op == OP_MATCH))
                                 return token->op == OP_MATCH;
                 return token->op == OP_NOMATCH;
         }
@@ -1637,7 +1637,7 @@ static int udev_rule_apply_token_to_event(
                 const char *val;
 
                 FOREACH_DEVICE_CURRENT_TAG(dev, val)
-                        if (token_match_string(token, val))
+                        if (token_match_string(token, val) == (token->op == OP_MATCH))
                                 return token->op == OP_MATCH;
                 return token->op == OP_NOMATCH;
         }