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Diffstat (limited to 'src/libbasic/smack-util.c')
| -rw-r--r-- | src/libbasic/smack-util.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/libbasic/smack-util.c b/src/libbasic/smack-util.c new file mode 100644 index 0000000000..3a3df987df --- /dev/null +++ b/src/libbasic/smack-util.c @@ -0,0 +1,241 @@ +/*** + This file is part of systemd. + + Copyright 2013 Intel Corporation + + Author: Auke Kok <auke-jan.h.kok@intel.com> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/xattr.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "fileio.h" +#include "log.h" +#include "macro.h" +#include "path-util.h" +#include "process-util.h" +#include "smack-util.h" +#include "string-table.h" +#include "xattr-util.h" + +#ifdef HAVE_SMACK +bool mac_smack_use(void) { + static int cached_use = -1; + + if (cached_use < 0) + cached_use = access("/sys/fs/smackfs/", F_OK) >= 0; + + return cached_use; +} + +static const char* const smack_attr_table[_SMACK_ATTR_MAX] = { + [SMACK_ATTR_ACCESS] = "security.SMACK64", + [SMACK_ATTR_EXEC] = "security.SMACK64EXEC", + [SMACK_ATTR_MMAP] = "security.SMACK64MMAP", + [SMACK_ATTR_TRANSMUTE] = "security.SMACK64TRANSMUTE", + [SMACK_ATTR_IPIN] = "security.SMACK64IPIN", + [SMACK_ATTR_IPOUT] = "security.SMACK64IPOUT", +}; + +DEFINE_STRING_TABLE_LOOKUP(smack_attr, SmackAttr); + +int mac_smack_read(const char *path, SmackAttr attr, char **label) { + assert(path); + assert(attr >= 0 && attr < _SMACK_ATTR_MAX); + assert(label); + + if (!mac_smack_use()) + return 0; + + return getxattr_malloc(path, smack_attr_to_string(attr), label, true); +} + +int mac_smack_read_fd(int fd, SmackAttr attr, char **label) { + assert(fd >= 0); + assert(attr >= 0 && attr < _SMACK_ATTR_MAX); + assert(label); + + if (!mac_smack_use()) + return 0; + + return fgetxattr_malloc(fd, smack_attr_to_string(attr), label); +} + +int mac_smack_apply(const char *path, SmackAttr attr, const char *label) { + int r; + + assert(path); + assert(attr >= 0 && attr < _SMACK_ATTR_MAX); + + if (!mac_smack_use()) + return 0; + + if (label) + r = lsetxattr(path, smack_attr_to_string(attr), label, strlen(label), 0); + else + r = lremovexattr(path, smack_attr_to_string(attr)); + if (r < 0) + return -errno; + + return 0; +} + +int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) { + int r; + + assert(fd >= 0); + assert(attr >= 0 && attr < _SMACK_ATTR_MAX); + + if (!mac_smack_use()) + return 0; + + if (label) + r = fsetxattr(fd, smack_attr_to_string(attr), label, strlen(label), 0); + else + r = fremovexattr(fd, smack_attr_to_string(attr)); + if (r < 0) + return -errno; + + return 0; +} + +int mac_smack_apply_pid(pid_t pid, const char *label) { + const char *p; + int r = 0; + + assert(label); + + if (!mac_smack_use()) + return 0; + + p = procfs_file_alloca(pid, "attr/current"); + r = write_string_file(p, label, 0); + if (r < 0) + return r; + + return r; +} + +int mac_smack_fix(const char *path, bool ignore_enoent, bool ignore_erofs) { + struct stat st; + int r = 0; + + assert(path); + + if (!mac_smack_use()) + return 0; + + /* + * Path must be in /dev and must exist + */ + if (!path_startswith(path, "/dev")) + return 0; + + r = lstat(path, &st); + if (r >= 0) { + const char *label; + + /* + * Label directories and character devices "*". + * Label symlinks "_". + * Don't change anything else. + */ + + if (S_ISDIR(st.st_mode)) + label = SMACK_STAR_LABEL; + else if (S_ISLNK(st.st_mode)) + label = SMACK_FLOOR_LABEL; + else if (S_ISCHR(st.st_mode)) + label = SMACK_STAR_LABEL; + else + return 0; + + r = lsetxattr(path, "security.SMACK64", label, strlen(label), 0); + + /* If the FS doesn't support labels, then exit without warning */ + if (r < 0 && errno == EOPNOTSUPP) + return 0; + } + + if (r < 0) { + /* Ignore ENOENT in some cases */ + if (ignore_enoent && errno == ENOENT) + return 0; + + if (ignore_erofs && errno == EROFS) + return 0; + + r = log_debug_errno(errno, "Unable to fix SMACK label of %s: %m", path); + } + + return r; +} + +int mac_smack_copy(const char *dest, const char *src) { + int r = 0; + _cleanup_free_ char *label = NULL; + + assert(dest); + assert(src); + + r = mac_smack_read(src, SMACK_ATTR_ACCESS, &label); + if (r < 0) + return r; + + r = mac_smack_apply(dest, SMACK_ATTR_ACCESS, label); + if (r < 0) + return r; + + return r; +} + +#else +bool mac_smack_use(void) { + return false; +} + +int mac_smack_read(const char *path, SmackAttr attr, char **label) { + return -EOPNOTSUPP; +} + +int mac_smack_read_fd(int fd, SmackAttr attr, char **label) { + return -EOPNOTSUPP; +} + +int mac_smack_apply(const char *path, SmackAttr attr, const char *label) { + return 0; +} + +int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) { + return 0; +} + +int mac_smack_apply_pid(pid_t pid, const char *label) { + return 0; +} + +int mac_smack_fix(const char *path, bool ignore_enoent, bool ignore_erofs) { + return 0; +} + +int mac_smack_copy(const char *dest, const char *src) { + return 0; +} +#endif |