checkpath: security fix for -m and -o options

Do not change permissions on the target if it is a file and has multiple
hard links. This is necessary because a hard link can be an attack
vector to gain privilege escalation.

X-Gentoo-Bug: 540006
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=540006
This commit is contained in:
William Hubbs 2015-02-15 14:56:07 -06:00
parent 3100114bc1
commit b17af3c85f

View File

@ -133,6 +133,10 @@ static int do_check(char *path, uid_t uid, gid_t gid, mode_t mode,
} }
if (mode && (st.st_mode & 0777) != mode) { if (mode && (st.st_mode & 0777) != mode) {
if ((type != inode_dir) && (st.st_nlink != 1)) {
eerror("%s: chown: %s %s", applet, "Too many hard links to", path);
return -1;
}
einfo("%s: correcting mode", path); einfo("%s: correcting mode", path);
if (chmod(path, mode)) { if (chmod(path, mode)) {
eerror("%s: chmod: %s", applet, strerror(errno)); eerror("%s: chmod: %s", applet, strerror(errno));
@ -141,6 +145,10 @@ static int do_check(char *path, uid_t uid, gid_t gid, mode_t mode,
} }
if (chowner && (st.st_uid != uid || st.st_gid != gid)) { if (chowner && (st.st_uid != uid || st.st_gid != gid)) {
if ((type != inode_dir) && (st.st_nlink != 1)) {
eerror("%s: chown: %s %s", applet, "Too many hard links to", path);
return -1;
}
einfo("%s: correcting owner", path); einfo("%s: correcting owner", path);
if (chown(path, uid, gid)) { if (chown(path, uid, gid)) {
eerror("%s: chown: %s", applet, strerror(errno)); eerror("%s: chown: %s", applet, strerror(errno));