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From 9ea44466541480b583032617e6060313f79a6bda Mon Sep 17 00:00:00 2001
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From: Martin Pitt <martin.pitt@ubuntu.com>
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Date: Thu, 14 May 2015 09:06:40 +0200
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Subject: [PATCH] core: Fix assertion with empty Exec*= paths
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An Exec*= line with whitespace after modifiers, like
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  ExecStart=- /bin/true
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is considered to have an empty command path. This is as specified, but causes
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systemd to crash with
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  Assertion 'skip < l' failed at ../src/core/load-fragment.c:607, function config_parse_exec(). Aborting.
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  Aborted (core dumped)
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Fix this by logging an error instead and ignoring the invalid line.
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Add corresponding test cases. Also add a test case for a completely empty value
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which resets the command list.
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https://launchpad.net/bugs/1454173
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Cherry-picked from: 35b1078e1c375df244e19961792aeb78ca34bb54
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Resolves: #1222517
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---
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 src/core/load-fragment.c  |  6 +++++-
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 src/test/test-unit-file.c | 21 +++++++++++++++++++++
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 2 files changed, 26 insertions(+), 1 deletion(-)
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diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
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index f17a82f..ec4cf4e 100644
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--- a/src/core/load-fragment.c
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+++ b/src/core/load-fragment.c
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@@ -604,7 +604,11 @@ int config_parse_exec(const char *unit,
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                                 skip = separate_argv0 + ignore;
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                                 /* skip special chars in the beginning */
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-                                assert(skip < l);
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+                                if (l <= skip) {
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+                                        log_syntax(unit, LOG_ERR, filename, line, EINVAL, "Empty path in command line, ignoring: %s", rvalue);
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+                                        r = 0;
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+                                        goto fail;
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+                                }
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                         } else if (strneq(word, ";", MAX(l, 1U)))
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                                 /* new commandline */
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diff --git a/src/test/test-unit-file.c b/src/test/test-unit-file.c
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index 9f3e3a2..5500983 100644
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--- a/src/test/test-unit-file.c
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+++ b/src/test/test-unit-file.c
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@@ -318,6 +318,27 @@ static void test_config_parse_exec(void) {
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         assert_se(r == 0);
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         assert_se(c1->command_next == NULL);
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+        log_info("/* invalid space between modifiers */");
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+        r = config_parse_exec(NULL, "fake", 4, "section", 1,
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+                              "LValue", 0, "- /path",
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+                              &c, NULL);
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+        assert_se(r == 0);
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+        assert_se(c1->command_next == NULL);
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+
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+        log_info("/* only modifiers, no path */");
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+        r = config_parse_exec(NULL, "fake", 4, "section", 1,
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+                              "LValue", 0, "-",
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+                              &c, NULL);
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+        assert_se(r == 0);
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+        assert_se(c1->command_next == NULL);
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+
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+        log_info("/* empty argument, reset */");
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+        r = config_parse_exec(NULL, "fake", 4, "section", 1,
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+                              "LValue", 0, "",
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+                              &c, NULL);
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+        assert_se(r == 0);
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+        assert_se(c == NULL);
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+
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         exec_command_free_list(c);
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 }
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