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From b7f8bd20b7fb5b72f003ae3fa647c1d75f4218b7 Mon Sep 17 00:00:00 2001
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From: Jakub Filak <jfilak@redhat.com>
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Date: Thu, 23 Apr 2015 14:40:18 +0200
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Subject: [ABRT PATCH] lib: add functions validating dump dir
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Move the code from abrt-server to shared library and fix the condition
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validating dump dir's path.
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As of now, abrt is allowed to process only direct sub-directories of the
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dump locations.
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Signed-off-by: Jakub Filak <jfilak@redhat.com>
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---
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 src/daemon/abrt-server.c | 42 ++++++------------------
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 src/include/libabrt.h    |  4 +++
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 src/lib/hooklib.c        | 56 +++++++++++++++++++++++++++++++
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 tests/Makefile.am        |  3 +-
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 tests/hooklib.at         | 85 ++++++++++++++++++++++++++++++++++++++++++++++++
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 tests/testsuite.at       |  1 +
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 6 files changed, 158 insertions(+), 33 deletions(-)
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 create mode 100644 tests/hooklib.at
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diff --git a/src/daemon/abrt-server.c b/src/daemon/abrt-server.c
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index 4d486d4..1030461 100644
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--- a/src/daemon/abrt-server.c
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+++ b/src/daemon/abrt-server.c
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@@ -76,20 +76,6 @@ static unsigned total_bytes_read = 0;
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 static uid_t client_uid = (uid_t)-1L;
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-static bool dir_is_in_dump_location(const char *dump_dir_name)
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-{
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-    unsigned len = strlen(g_settings_dump_location);
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-
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-    if (strncmp(dump_dir_name, g_settings_dump_location, len) == 0
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-     && dump_dir_name[len] == '/'
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-    /* must not contain "/." anywhere (IOW: disallow ".." component) */
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-     && !strstr(dump_dir_name + len, "/.")
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-    ) {
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-        return 1;
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-    }
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-    return 0;
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-}
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-
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 /* Remove dump dir */
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 static int delete_path(const char *dump_dir_name)
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 {
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@@ -100,6 +86,11 @@ static int delete_path(const char *dump_dir_name)
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         error_msg("Bad problem directory name '%s', should start with: '%s'", dump_dir_name, g_settings_dump_location);
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         return 400; /* Bad Request */
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     }
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+    if (!dir_has_correct_permissions(dump_dir_name))
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+    {
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+        error_msg("Problem directory '%s' isn't owned by root:abrt or others are not restricted from access", dump_dir_name);
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+        return 400; /*  */
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+    }
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     if (!dump_dir_accessible_by_uid(dump_dir_name, client_uid))
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     {
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         if (errno == ENOTDIR)
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@@ -154,26 +145,13 @@ static int run_post_create(const char *dirname)
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         error_msg("Bad problem directory name '%s', should start with: '%s'", dirname, g_settings_dump_location);
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         return 400; /* Bad Request */
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     }
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+    if (!dir_has_correct_permissions(dirname))
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+    {
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+        error_msg("Problem directory '%s' isn't owned by root:abrt or others are not restricted from access", dirname);
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+        return 400; /*  */
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+    }
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     if (g_settings_privatereports)
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     {
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-        struct stat statbuf;
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-        if (lstat(dirname, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
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-        {
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-            error_msg("Path '%s' isn't directory", dirname);
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-            return 404; /* Not Found */
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-        }
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-        /* Get ABRT's group gid */
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-        struct group *gr = getgrnam("abrt");
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-        if (!gr)
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-        {
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-            error_msg("Group 'abrt' does not exist");
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-            return 500;
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-        }
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-        if (statbuf.st_uid != 0 || !(statbuf.st_gid == 0 || statbuf.st_gid == gr->gr_gid) || statbuf.st_mode & 07)
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-        {
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-            error_msg("Problem directory '%s' isn't owned by root:abrt or others are not restricted from access", dirname);
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-            return 403;
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-        }
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         struct dump_dir *dd = dd_opendir(dirname, DD_OPEN_READONLY);
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         const bool complete = dd && problem_dump_dir_is_complete(dd);
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         dd_close(dd);
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diff --git a/src/include/libabrt.h b/src/include/libabrt.h
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index 0320c5b..5bf2397 100644
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--- a/src/include/libabrt.h
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+++ b/src/include/libabrt.h
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@@ -47,6 +47,10 @@ char *run_unstrip_n(const char *dump_dir_name, unsigned timeout_sec);
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 #define get_backtrace abrt_get_backtrace
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 char *get_backtrace(const char *dump_dir_name, unsigned timeout_sec, const char *debuginfo_dirs);
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+#define dir_is_in_dump_location abrt_dir_is_in_dump_location
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+bool dir_is_in_dump_location(const char *dir_name);
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+#define dir_has_correct_permissions abrt_dir_has_correct_permissions
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+bool dir_has_correct_permissions(const char *dir_name);
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 #define g_settings_nMaxCrashReportsSize abrt_g_settings_nMaxCrashReportsSize
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 extern unsigned int  g_settings_nMaxCrashReportsSize;
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diff --git a/src/lib/hooklib.c b/src/lib/hooklib.c
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index fb7750d..4b20025 100644
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--- a/src/lib/hooklib.c
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+++ b/src/lib/hooklib.c
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@@ -427,3 +427,59 @@ char* problem_data_save(problem_data_t *pd)
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     log_info("problem id: '%s'", problem_id);
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     return problem_id;
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 }
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+
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+bool dir_is_in_dump_location(const char *dir_name)
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+{
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+    unsigned len = strlen(g_settings_dump_location);
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+
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+    /* The path must start with "g_settings_dump_location" */
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+    if (strncmp(dir_name, g_settings_dump_location, len) != 0)
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+    {
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+        log_debug("Bad parent directory: '%s' not in '%s'", g_settings_dump_location, dir_name);
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+        return false;
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+    }
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+
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+    /* and must be a sub-directory of the g_settings_dump_location dir */
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+    const char *base_name = dir_name + len;
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+    while (*base_name && *base_name == '/')
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+        ++base_name;
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+
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+    if (*(base_name - 1) != '/' || !str_is_correct_filename(base_name))
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+    {
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+        log_debug("Invalid dump directory name: '%s'", base_name);
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+        return false;
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+    }
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+
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+    /* and we are sure it is a directory */
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+    struct stat sb;
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+    if (lstat(dir_name, &sb) < 0)
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+    {
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+        VERB2 perror_msg("stat('%s')", dir_name);
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+        return errno== ENOENT;
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+    }
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+
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+    return S_ISDIR(sb.st_mode);
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+}
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+
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+bool dir_has_correct_permissions(const char *dir_name)
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+{
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+    if (g_settings_privatereports)
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+    {
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+        struct stat statbuf;
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+        if (lstat(dir_name, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
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+        {
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+            error_msg("Path '%s' isn't directory", dir_name);
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+            return false;
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+        }
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+        /* Get ABRT's group gid */
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+        struct group *gr = getgrnam("abrt");
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+        if (!gr)
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+        {
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+            error_msg("Group 'abrt' does not exist");
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+            return false;
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+        }
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+        if (statbuf.st_uid != 0 || !(statbuf.st_gid == 0 || statbuf.st_gid == gr->gr_gid) || statbuf.st_mode & 07)
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+            return false;
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+    }
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+    return true;
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+}
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diff --git a/tests/Makefile.am b/tests/Makefile.am
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index 5ef08a0..416f579 100644
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--- a/tests/Makefile.am
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+++ b/tests/Makefile.am
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@@ -29,7 +29,8 @@ TESTSUITE_AT = \
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   testsuite.at \
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   pyhook.at \
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   koops-parser.at \
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-  ignored_problems.at
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+  ignored_problems.at \
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+  hooklib.at
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 EXTRA_DIST += $(TESTSUITE_AT)
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 TESTSUITE = $(srcdir)/testsuite
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diff --git a/tests/hooklib.at b/tests/hooklib.at
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new file mode 100644
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index 0000000..70631c6
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--- /dev/null
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+++ b/tests/hooklib.at
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@@ -0,0 +1,85 @@
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+# -*- Autotest -*-
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+
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+AT_BANNER([hooklib])
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+
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+AT_TESTFUN([dir_is_in_dump_location],
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+[[
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+#include "libabrt.h"
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+#include <assert.h>
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+
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+void test(char *name, bool expected)
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+{
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+    if (dir_is_in_dump_location(name) != expected)
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+    {
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+        fprintf(stderr, "Bad: %s", name);
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+        abort();
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+    }
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+
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+    free(name);
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+}
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+
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+int main(void)
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+{
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+    g_verbose = 3;
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+    load_abrt_conf();
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+
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+    g_verbose = 3;
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+
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+    char *name;
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+
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+    assert(dir_is_in_dump_location("/") == false);
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+
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+    asprintf(&name, "%s", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s..evil", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s///", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/.", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s///.", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/./", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/.///", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/..", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s///..", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/../", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/..///", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/good/../../../evil", g_settings_dump_location);
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+    test(name, false);
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+
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+    asprintf(&name, "%s/good..still", g_settings_dump_location);
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+    test(name, true);
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+
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+    asprintf(&name, "%s/good.new", g_settings_dump_location);
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+    test(name, true);
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+
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+    asprintf(&name, "%s/.meta", g_settings_dump_location);
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+    test(name, true);
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+
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+    asprintf(&name, "%s/..data", g_settings_dump_location);
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+    test(name, true);
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+
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+    return 0;
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+}
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+]])
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diff --git a/tests/testsuite.at b/tests/testsuite.at
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index b8f363d..765de2a 100644
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--- a/tests/testsuite.at
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+++ b/tests/testsuite.at
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@@ -4,3 +4,4 @@
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 m4_include([koops-parser.at])
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 m4_include([pyhook.at])
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 m4_include([ignored_problems.at])
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+m4_include([hooklib.at])
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-- 
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1.8.3.1
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