From 40826f4ed0b325961d23f1e5dda45215bdb120c0 Mon Sep 17 00:00:00 2001

From: Jakub Filak <jfilak@redhat.com>

Date: Wed, 30 Sep 2015 14:13:35 +0200

Subject: [PATCH] lib: add convenient wrappers for ensuring writable dir

Replace lchown with fchown and chmod with fchmod.

Related to CVE-2015-5287

Related: #1262252

Signed-off-by: Jakub Filak <jfilak@redhat.com>

---

 src/daemon/abrtd.c    | 19 -------------------

 src/include/libabrt.h |  6 ++++++

 src/lib/hooklib.c     | 46 ++++++++++++++++++++++++++++++++++++++++++++++

 3 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/src/daemon/abrtd.c b/src/daemon/abrtd.c

index b8426dd..b1252d2 100644

--- a/src/daemon/abrtd.c

+++ b/src/daemon/abrtd.c

@@ -158,25 +158,6 @@ static gboolean handle_signal_cb(GIOChannel *gio, GIOCondition condition, gpoint

     return TRUE; /* "please don't remove this event" */

 }

-static void ensure_writable_dir(const char *dir, mode_t mode, const char *user)

-{

-    struct stat sb;

-

-    if (mkdir(dir, mode) != 0 && errno != EEXIST)

-        perror_msg_and_die("Can't create '%s'", dir);

-    if (stat(dir, &sb) != 0 || !S_ISDIR(sb.st_mode))

-        error_msg_and_die("'%s' is not a directory", dir);

-

-    struct passwd *pw = getpwnam(user);

-    if (!pw)

-        perror_msg_and_die("Can't find user '%s'", user);

-

-    if ((sb.st_uid != pw->pw_uid || sb.st_gid != pw->pw_gid) && lchown(dir, pw->pw_uid, pw->pw_gid) != 0)

-        perror_msg_and_die("Can't set owner %u:%u on '%s'", (unsigned int)pw->pw_uid, (unsigned int)pw->pw_gid, dir);

-    if ((sb.st_mode & 07777) != mode && chmod(dir, mode) != 0)

-        perror_msg_and_die("Can't set mode %o on '%s'", mode, dir);

-}

-

 static void sanitize_dump_dir_rights(void)

 {

     /* We can't allow everyone to create dumps: otherwise users can flood

diff --git a/src/include/libabrt.h b/src/include/libabrt.h

index 21ce440..2510a77 100644

--- a/src/include/libabrt.h

+++ b/src/include/libabrt.h

@@ -42,6 +42,12 @@ int low_free_space(unsigned setting_MaxCrashReportsSize, const char *dump_locati

 #define trim_problem_dirs abrt_trim_problem_dirs

 void trim_problem_dirs(const char *dirname, double cap_size, const char *exclude_path);

+#define ensure_writable_dir_id abrt_ensure_writable_dir_uid_git

+void ensure_writable_dir_uid_gid(const char *dir, mode_t mode, uid_t uid, gid_t gid);

+#define ensure_writable_dir abrt_ensure_writable_dir

+void ensure_writable_dir(const char *dir, mode_t mode, const char *user);

+#define ensure_writable_dir_group abrt_ensure_writable_dir_group

+void ensure_writable_dir_group(const char *dir, mode_t mode, const char *user, const char *group);

 #define run_unstrip_n abrt_run_unstrip_n

 char *run_unstrip_n(const char *dump_dir_name, unsigned timeout_sec);

 #define get_backtrace abrt_get_backtrace

diff --git a/src/lib/hooklib.c b/src/lib/hooklib.c

index 8e93663..160a011 100644

--- a/src/lib/hooklib.c

+++ b/src/lib/hooklib.c

@@ -428,6 +428,52 @@ char* problem_data_save(problem_data_t *pd)

     return problem_id;

 }

+void ensure_writable_dir_uid_gid(const char *dir, mode_t mode, uid_t uid, gid_t gid)

+{

+    struct stat sb;

+    int dir_fd;

+

+    if (mkdir(dir, mode) != 0 && errno != EEXIST)

+        perror_msg_and_die("Can't create '%s'", dir);

+

+    dir_fd = open(dir, O_DIRECTORY | O_NOFOLLOW);

+    if (dir_fd < 0)

+        perror_msg_and_die("Can't open directory '%s'", dir);

+

+    if (fstat(dir_fd, &sb) != 0)

+        perror_msg_and_die("Can't stat directory '%s'", dir);

+

+    if ((sb.st_uid != uid || sb.st_gid != gid) && fchown(dir_fd, uid, gid) != 0)

+        perror_msg_and_die("Can't set owner %u:%u on '%s'", (unsigned int)uid, (unsigned int)gid, dir);

+

+    if ((sb.st_mode & 07777) != mode && fchmod(dir_fd, mode) != 0)

+        perror_msg_and_die("Can't set mode %o on '%s'", mode, dir);

+

+    close(dir_fd);

+}

+

+void ensure_writable_dir(const char *dir, mode_t mode, const char *user)

+{

+    struct passwd *pw = getpwnam(user);

+    if (!pw)

+        perror_msg_and_die("Can't find user '%s'", user);

+

+    ensure_writable_dir_uid_gid(dir, mode, pw->pw_uid, pw->pw_gid);

+}

+

+void ensure_writable_dir_group(const char *dir, mode_t mode, const char *user, const char *group)

+{

+    struct passwd *pw = getpwnam(user);

+    if (!pw)

+        perror_msg_and_die("Can't find user '%s'", user);

+

+    struct group *gr = getgrnam(group);

+    if (!gr)

+        perror_msg_and_die("Can't find group '%s'", group);

+

+    ensure_writable_dir_uid_gid(dir, mode, pw->pw_uid, gr->gr_gid);

+}

+

 bool dir_is_in_dump_location(const char *dir_name)

 {

     unsigned len = strlen(g_settings_dump_location);

-- 

1.8.3.1