X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fshared%2Flabel.c;h=b6af38d82d39a0940c6133c4ca886d7384c59cdb;hp=2d7d42a40e7338a7f2ceb83266ab1399a5b5d34a;hb=493d521d9ffe706741665a88ea14929913ea2eaf;hpb=9eb977db5b89b44f254ab40c1876a76b7d7ea2d0

diff --git a/src/shared/label.c b/src/shared/label.c
index 2d7d42a40..b6af38d82 100644
--- a/src/shared/label.c
+++ b/src/shared/label.c
@@ -20,38 +20,78 @@
 ***/
 
 #include <errno.h>
-#include <sys/stat.h>
 #include <unistd.h>
 #include <malloc.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/xattr.h>
+#ifdef HAVE_SELINUX
+#include <selinux/selinux.h>
+#include <selinux/label.h>
+#include <selinux/context.h>
+#endif
 
 #include "label.h"
+#include "strv.h"
 #include "util.h"
 #include "path-util.h"
+#include "selinux-util.h"
+#include "smack-util.h"
 
 #ifdef HAVE_SELINUX
-#include <selinux/selinux.h>
-#include <selinux/label.h>
+DEFINE_TRIVIAL_CLEANUP_FUNC(security_context_t, freecon);
+DEFINE_TRIVIAL_CLEANUP_FUNC(context_t, context_free);
 
-static struct selabel_handle *label_hnd = NULL;
+#define _cleanup_security_context_free_ _cleanup_(freeconp)
+#define _cleanup_context_free_ _cleanup_(context_freep)
 
-static int use_selinux_cached = -1;
+static struct selabel_handle *label_hnd = NULL;
+#endif
 
-static inline bool use_selinux(void) {
+static int smack_relabel_in_dev(const char *path) {
+        int r = 0;
 
-        if (use_selinux_cached < 0)
-                use_selinux_cached = is_selinux_enabled() > 0;
+#ifdef HAVE_SMACK
+        struct stat sb;
+        const char *label;
 
-        return use_selinux_cached;
-}
+        /*
+         * Path must be in /dev and must exist
+         */
+        if (!path_startswith(path, "/dev"))
+                return 0;
 
-void label_retest_selinux(void) {
-        use_selinux_cached = -1;
-}
+        r = lstat(path, &sb);
+        if (r < 0)
+                return -errno;
+
+        /*
+         * Label directories and character devices "*".
+         * Label symlinks "_".
+         * Don't change anything else.
+         */
+        if (S_ISDIR(sb.st_mode))
+                label = SMACK_STAR_LABEL;
+        else if (S_ISLNK(sb.st_mode))
+                label = SMACK_FLOOR_LABEL;
+        else if (S_ISCHR(sb.st_mode))
+                label = SMACK_STAR_LABEL;
+        else
+                return 0;
 
+        r = setxattr(path, "security.SMACK64", label, strlen(label), 0);
+        if (r < 0) {
+                log_error("Smack relabeling \"%s\" %m", path);
+                return -errno;
+        }
 #endif
 
+        return r;
+}
+
 int label_init(const char *prefix) {
         int r = 0;
 
@@ -90,23 +130,23 @@ int label_init(const char *prefix) {
 
                 l = after_mallinfo.uordblks > before_mallinfo.uordblks ? after_mallinfo.uordblks - before_mallinfo.uordblks : 0;
 
-                log_info("Successfully loaded SELinux database in %s, size on heap is %iK.",
-                         format_timespan(timespan, sizeof(timespan), after_timestamp - before_timestamp),
-                         (l+1023)/1024);
+                log_debug("Successfully loaded SELinux database in %s, size on heap is %iK.",
+                          format_timespan(timespan, sizeof(timespan), after_timestamp - before_timestamp, 0),
+                          (l+1023)/1024);
         }
 #endif
 
         return r;
 }
 
-int label_fix(const char *path, bool ignore_enoent) {
+static int label_fix_selinux(const char *path, bool ignore_enoent, bool ignore_erofs) {
         int r = 0;
 
 #ifdef HAVE_SELINUX
         struct stat st;
         security_context_t fcon;
 
-        if (!use_selinux() || !label_hnd)
+        if (!label_hnd)
                 return 0;
 
         r = lstat(path, &st);
@@ -132,6 +172,9 @@ int label_fix(const char *path, bool ignore_enoent) {
                 if (ignore_enoent && errno == ENOENT)
                         return 0;
 
+                if (ignore_erofs && errno == EROFS)
+                        return 0;
+
                 log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
                          "Unable to fix label of %s: %m", path);
                 r = security_getenforce() == 1 ? -errno : 0;
@@ -141,10 +184,31 @@ int label_fix(const char *path, bool ignore_enoent) {
         return r;
 }
 
+int label_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
+        int r = 0;
+
+        if (use_selinux()) {
+                r = label_fix_selinux(path, ignore_enoent, ignore_erofs);
+                if (r < 0)
+                        return r;
+        }
+
+        if (use_smack()) {
+                r = smack_relabel_in_dev(path);
+                if (r < 0)
+                        return r;
+        }
+
+        return r;
+}
+
 void label_finish(void) {
 
 #ifdef HAVE_SELINUX
-        if (use_selinux() && label_hnd)
+        if (!use_selinux())
+                return;
+
+        if (label_hnd)
                 selabel_close(label_hnd);
 #endif
 }
@@ -186,6 +250,113 @@ fail:
         return r;
 }
 
+int label_get_our_label(char **label) {
+        int r = -EOPNOTSUPP;
+
+#ifdef HAVE_SELINUX
+        char *l = NULL;
+
+        r = getcon(&l);
+        if (r < 0)
+                return r;
+
+        *label = l;
+#endif
+
+        return r;
+}
+
+int label_get_child_mls_label(int socket_fd, const char *exe, char **label) {
+        int r = -EOPNOTSUPP;
+
+#ifdef HAVE_SELINUX
+
+        _cleanup_security_context_free_ security_context_t mycon = NULL, peercon = NULL, fcon = NULL, ret = NULL;
+        _cleanup_context_free_ context_t pcon = NULL, bcon = NULL;
+        security_class_t sclass;
+
+        const char *range = NULL;
+
+        assert(socket_fd >= 0);
+        assert(exe);
+        assert(label);
+
+        r = getcon(&mycon);
+        if (r < 0) {
+                r = -EINVAL;
+                goto out;
+        }
+
+        r = getpeercon(socket_fd, &peercon);
+        if (r < 0) {
+                r = -EINVAL;
+                goto out;
+        }
+
+        r = getexeccon(&fcon);
+        if (r < 0) {
+                r = -EINVAL;
+                goto out;
+        }
+
+        if (!fcon) {
+                /* If there is no context set for next exec let's use context
+                   of target executable */
+                r = getfilecon(exe, &fcon);
+                if (r < 0) {
+                        r = -errno;
+                        goto out;
+                }
+        }
+
+        bcon = context_new(mycon);
+        if (!bcon) {
+                r = -ENOMEM;
+                goto out;
+        }
+
+        pcon = context_new(peercon);
+        if (!pcon) {
+                r = -ENOMEM;
+                goto out;
+        }
+
+        range = context_range_get(pcon);
+        if (!range) {
+                r = -errno;
+                goto out;
+        }
+
+        r = context_range_set(bcon, range);
+        if (r) {
+                r = -errno;
+                goto out;
+        }
+
+        freecon(mycon);
+        mycon = context_str(bcon);
+        if (!mycon) {
+                r = -errno;
+                goto out;
+        }
+
+        sclass = string_to_security_class("process");
+        r = security_compute_create(mycon, fcon, sclass, &ret);
+        if (r < 0) {
+                r = -EINVAL;
+                goto out;
+        }
+
+        *label = ret;
+        r = 0;
+
+out:
+        if (r < 0 && security_getenforce() == 1)
+                return r;
+#endif
+        return r;
+}
+
 int label_context_set(const char *path, mode_t mode) {
         int r = 0;
 
@@ -196,7 +367,7 @@ int label_context_set(const char *path, mode_t mode) {
                 return 0;
 
         r = selabel_lookup_raw(label_hnd, &filecon, path, mode);
-        if (r < 0)
+        if (r < 0 && errno != ENOENT)
                 r = -errno;
         else if (r == 0) {
                 r = setfscreatecon(filecon);
@@ -236,6 +407,8 @@ int label_socket_set(const char *label) {
 void label_context_clear(void) {
 
 #ifdef HAVE_SELINUX
+        PROTECT_ERRNO;
+
         if (!use_selinux())
                 return;
 
@@ -246,6 +419,8 @@ void label_context_clear(void) {
 void label_socket_clear(void) {
 
 #ifdef HAVE_SELINUX
+        PROTECT_ERRNO;
+
         if (!use_selinux())
                 return;
 
@@ -263,28 +438,26 @@ void label_free(const char *label) {
 #endif
 }
 
-int label_mkdir(const char *path, mode_t mode) {
-
-        /* Creates a directory and labels it according to the SELinux policy */
+static int label_mkdir_selinux(const char *path, mode_t mode) {
+        int r = 0;
 
 #ifdef HAVE_SELINUX
-        int r;
+        /* Creates a directory and labels it according to the SELinux policy */
         security_context_t fcon = NULL;
 
-        if (!use_selinux() || !label_hnd)
-                goto skipped;
+        if (!label_hnd)
+                return 0;
 
         if (path_is_absolute(path))
                 r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFDIR);
         else {
-                char *newpath;
+                _cleanup_free_ char *newpath;
 
                 newpath = path_make_absolute_cwd(path);
                 if (!newpath)
                         return -ENOMEM;
 
                 r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFDIR);
-                free(newpath);
         }
 
         if (r == 0)
@@ -306,12 +479,35 @@ int label_mkdir(const char *path, mode_t mode) {
 finish:
         setfscreatecon(NULL);
         freecon(fcon);
+#endif
 
         return r;
+}
 
-skipped:
-#endif
-        return mkdir(path, mode) < 0 ? -errno : 0;
+int label_mkdir(const char *path, mode_t mode) {
+        int r;
+
+        if (use_selinux()) {
+                r = label_mkdir_selinux(path, mode);
+                if (r < 0)
+                        return r;
+        }
+
+        if (use_smack()) {
+                r = mkdir(path, mode);
+                if (r < 0 && errno != EEXIST)
+                        return -errno;
+
+                r = smack_relabel_in_dev(path);
+                if (r < 0)
+                        return r;
+        }
+
+        r = mkdir(path, mode);
+        if (r < 0 && errno != EEXIST)
+                return -errno;
+
+        return 0;
 }
 
 int label_bind(int fd, const struct sockaddr *addr, socklen_t addrlen) {
@@ -319,10 +515,10 @@ int label_bind(int fd, const struct sockaddr *addr, socklen_t addrlen) {
         /* Binds a socket and label its file system object according to the SELinux policy */
 
 #ifdef HAVE_SELINUX
-        int r;
         security_context_t fcon = NULL;
         const struct sockaddr_un *un;
-        char *path = NULL;
+        char *path;
+        int r;
 
         assert(fd >= 0);
         assert(addr);
@@ -344,24 +540,18 @@ int label_bind(int fd, const struct sockaddr *addr, socklen_t addrlen) {
         if (un->sun_path[0] == 0)
                 goto skipped;
 
-        path = strndup(un->sun_path, addrlen - offsetof(struct sockaddr_un, sun_path));
-        if (!path)
-                return -ENOMEM;
+        path = strndupa(un->sun_path, addrlen - offsetof(struct sockaddr_un, sun_path));
 
         if (path_is_absolute(path))
                 r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFSOCK);
         else {
-                char *newpath;
+                _cleanup_free_ char *newpath;
 
                 newpath = path_make_absolute_cwd(path);
-
-                if (!newpath) {
-                        free(path);
+                if (!newpath)
                         return -ENOMEM;
-                }
 
                 r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFSOCK);
-                free(newpath);
         }
 
         if (r == 0)
@@ -383,7 +573,6 @@ int label_bind(int fd, const struct sockaddr *addr, socklen_t addrlen) {
 finish:
         setfscreatecon(NULL);
         freecon(fcon);
-        free(path);
 
         return r;
 
@@ -391,3 +580,15 @@ skipped:
 #endif
         return bind(fd, addr, addrlen) < 0 ? -errno : 0;
 }
+
+int label_apply(const char *path, const char *label) {
+        int r = 0;
+
+#ifdef HAVE_SELINUX
+        if (!use_selinux())
+                return 0;
+
+        r = setfilecon(path, (char *)label);
+#endif
+        return r;
+}