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From d8a3bd0d464f5b75ac360f4ee4e3cc6927a09199 Mon Sep 17 00:00:00 2001
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From: Jakub Filak <jfilak@redhat.com>
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Date: Wed, 30 Sep 2015 14:13:35 +0200
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Subject: [PATCH] lib: add convenient wrappers for ensuring writable dir
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Replace lchown with fchown and chmod with fchmod.
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Related CVE-2015-5287
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Signed-off-by: Jakub Filak <jfilak@redhat.com>
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---
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 src/include/libabrt.h |  4 ++++
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 src/lib/hooklib.c     | 41 ++++++++++++++++++++++++++++++++++-------
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 2 files changed, 38 insertions(+), 7 deletions(-)
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diff --git a/src/include/libabrt.h b/src/include/libabrt.h
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index 6f89959..b26dcc6 100644
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--- a/src/include/libabrt.h
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+++ b/src/include/libabrt.h
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@@ -42,8 +42,12 @@ int low_free_space(unsigned setting_MaxCrashReportsSize, const char *dump_locati
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 #define trim_problem_dirs abrt_trim_problem_dirs
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 void trim_problem_dirs(const char *dirname, double cap_size, const char *exclude_path);
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+#define ensure_writable_dir_id abrt_ensure_writable_dir_uid_git
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+void ensure_writable_dir_uid_gid(const char *dir, mode_t mode, uid_t uid, gid_t gid);
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 #define ensure_writable_dir abrt_ensure_writable_dir
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 void ensure_writable_dir(const char *dir, mode_t mode, const char *user);
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+#define ensure_writable_dir_group abrt_ensure_writable_dir_group
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+void ensure_writable_dir_group(const char *dir, mode_t mode, const char *user, const char *group);
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 #define run_unstrip_n abrt_run_unstrip_n
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 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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diff --git a/src/lib/hooklib.c b/src/lib/hooklib.c
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index 2b76eea..0daa144 100644
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--- a/src/lib/hooklib.c
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+++ b/src/lib/hooklib.c
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@@ -476,23 +476,50 @@ int signal_is_fatal(int signal_no, const char **name)
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     return signame != NULL;
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 }
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-void ensure_writable_dir(const char *dir, mode_t mode, const char *user)
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+void ensure_writable_dir_uid_gid(const char *dir, mode_t mode, uid_t uid, gid_t gid)
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 {
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     struct stat sb;
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+    int dir_fd;
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     if (mkdir(dir, mode) != 0 && errno != EEXIST)
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         perror_msg_and_die("Can't create '%s'", dir);
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-    if (stat(dir, &sb) != 0 || !S_ISDIR(sb.st_mode))
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-        error_msg_and_die("'%s' is not a directory", dir);
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+    dir_fd = open(dir, O_DIRECTORY | O_NOFOLLOW);
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+    if (dir_fd < 0)
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+        perror_msg_and_die("Can't open directory '%s'", dir);
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+
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+    if (fstat(dir_fd, &sb) != 0)
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+        perror_msg_and_die("Can't stat directory '%s'", dir);
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+
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+    if ((sb.st_uid != uid || sb.st_gid != gid) && fchown(dir_fd, uid, gid) != 0)
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+        perror_msg_and_die("Can't set owner %u:%u on '%s'", (unsigned int)uid, (unsigned int)gid, dir);
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+
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+    if ((sb.st_mode & 07777) != mode && fchmod(dir_fd, mode) != 0)
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+        perror_msg_and_die("Can't set mode %o on '%s'", mode, dir);
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+
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+    close(dir_fd);
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+}
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+
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+void ensure_writable_dir(const char *dir, mode_t mode, const char *user)
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+{
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+    struct passwd *pw = getpwnam(user);
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+    if (!pw)
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+        perror_msg_and_die("Can't find user '%s'", user);
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+
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+    ensure_writable_dir_uid_gid(dir, mode, pw->pw_uid, pw->pw_gid);
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+}
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+
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+void ensure_writable_dir_group(const char *dir, mode_t mode, const char *user, const char *group)
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+{
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     struct passwd *pw = getpwnam(user);
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     if (!pw)
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         perror_msg_and_die("Can't find user '%s'", user);
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-    if ((sb.st_uid != pw->pw_uid || sb.st_gid != pw->pw_gid) && lchown(dir, pw->pw_uid, pw->pw_gid) != 0)
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-        perror_msg_and_die("Can't set owner %u:%u on '%s'", (unsigned int)pw->pw_uid, (unsigned int)pw->pw_gid, dir);
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-    if ((sb.st_mode & 07777) != mode && chmod(dir, mode) != 0)
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-        perror_msg_and_die("Can't set mode %o on '%s'", mode, dir);
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+    struct group *gr = getgrnam(group);
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+    if (!gr)
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+        perror_msg_and_die("Can't find group '%s'", group);
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+
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+    ensure_writable_dir_uid_gid(dir, mode, pw->pw_uid, gr->gr_gid);
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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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2.6.3
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