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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/***
Copyright © 2012 Roberto Sassu - Politecnico di Torino, Italy
TORSEC group — http://security.polito.it
***/
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "ima-setup.h"
#include "log.h"
#define IMA_SECFS_DIR "/sys/kernel/security/ima"
#define IMA_SECFS_POLICY IMA_SECFS_DIR "/policy"
#define IMA_POLICY_PATH "/etc/ima/ima-policy"
int ima_setup(void) {
#if ENABLE_IMA
_cleanup_fclose_ FILE *input = NULL;
_cleanup_close_ int imafd = -1;
unsigned lineno = 0;
int r;
if (access(IMA_SECFS_DIR, F_OK) < 0) {
log_debug_errno(errno, "IMA support is disabled in the kernel, ignoring: %m");
return 0;
}
if (access(IMA_SECFS_POLICY, W_OK) < 0) {
log_warning_errno(errno, "Another IMA custom policy has already been loaded, ignoring: %m");
return 0;
}
if (access(IMA_POLICY_PATH, F_OK) < 0) {
log_debug_errno(errno, "No IMA custom policy file "IMA_POLICY_PATH", ignoring: %m");
return 0;
}
imafd = open(IMA_SECFS_POLICY, O_WRONLY|O_CLOEXEC);
if (imafd < 0) {
log_error_errno(errno, "Failed to open the IMA kernel interface "IMA_SECFS_POLICY", ignoring: %m");
return 0;
}
/* attempt to write the name of the policy file into sysfs file */
if (write(imafd, IMA_POLICY_PATH, STRLEN(IMA_POLICY_PATH)) > 0)
goto done;
/* fall back to copying the policy line-by-line */
input = fopen(IMA_POLICY_PATH, "re");
if (!input) {
log_warning_errno(errno, "Failed to open the IMA custom policy file "IMA_POLICY_PATH", ignoring: %m");
return 0;
}
safe_close(imafd);
imafd = open(IMA_SECFS_POLICY, O_WRONLY|O_CLOEXEC);
if (imafd < 0) {
log_error_errno(errno, "Failed to open the IMA kernel interface "IMA_SECFS_POLICY", ignoring: %m");
return 0;
}
for (;;) {
_cleanup_free_ char *line = NULL;
size_t len;
r = read_line(input, LONG_LINE_MAX, &line);
if (r < 0)
return log_error_errno(r, "Failed to read the IMA custom policy file "IMA_POLICY_PATH": %m");
if (r == 0)
break;
len = strlen(line);
lineno++;
if (len > 0 && write(imafd, line, len) < 0)
return log_error_errno(errno, "Failed to load the IMA custom policy file "IMA_POLICY_PATH"%u: %m",
lineno);
}
done:
log_info("Successfully loaded the IMA custom policy "IMA_POLICY_PATH".");
#endif /* ENABLE_IMA */
return 0;
}
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