23769fb371
Let's do some rearrangements, so that we can later on use this to automatically search for a key file.
111 lines
3.9 KiB
C
111 lines
3.9 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <unistd.h>
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#include "cryptsetup-util.h"
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#include "fd-util.h"
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#include "format-util.h"
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#include "memory-util.h"
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#include "path-util.h"
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#include "stat-util.h"
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#include "strv.h"
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#define KEY_FILE_SIZE_MAX (16U*1024U*1024U) /* 16 MiB */
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int load_key_file(
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const char *key_file,
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char **search_path,
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size_t key_file_size,
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uint64_t key_file_offset,
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void **ret_key,
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size_t *ret_key_size) {
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_cleanup_(erase_and_freep) char *buffer = NULL;
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_cleanup_free_ char *discovered_path = NULL;
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_cleanup_close_ int fd = -1;
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ssize_t n;
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int r;
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assert(key_file);
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assert(ret_key);
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assert(ret_key_size);
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if (strv_isempty(search_path) || path_is_absolute(key_file)) {
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fd = open(key_file, O_RDONLY|O_CLOEXEC);
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if (fd < 0)
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return log_error_errno(errno, "Failed to load key file '%s': %m", key_file);
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} else {
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char **i;
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STRV_FOREACH(i, search_path) {
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_cleanup_free_ char *joined;
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joined = path_join(*i, key_file);
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if (!joined)
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return log_oom();
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fd = open(joined, O_RDONLY|O_CLOEXEC);
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if (fd >= 0) {
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discovered_path = TAKE_PTR(joined);
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break;
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}
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if (errno != ENOENT)
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return log_error_errno(errno, "Failed to load key file '%s': %m", joined);
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}
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if (!discovered_path) {
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/* Search path supplied, but file not found, report by returning NULL, but not failing */
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*ret_key = NULL;
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*ret_key_size = 0;
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return 0;
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}
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assert(fd >= 0);
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key_file = discovered_path;
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}
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if (key_file_size == 0) {
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struct stat st;
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if (fstat(fd, &st) < 0)
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return log_error_errno(errno, "Failed to stat key file '%s': %m", key_file);
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r = stat_verify_regular(&st);
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if (r < 0)
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return log_error_errno(r, "Key file is not a regular file: %m");
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if (st.st_size == 0)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Key file is empty, refusing.");
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if ((uint64_t) st.st_size > KEY_FILE_SIZE_MAX) {
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char buf1[FORMAT_BYTES_MAX], buf2[FORMAT_BYTES_MAX];
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return log_error_errno(SYNTHETIC_ERRNO(ERANGE),
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"Key file larger (%s) than allowed maximum size (%s), refusing.",
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format_bytes(buf1, sizeof(buf1), st.st_size),
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format_bytes(buf2, sizeof(buf2), KEY_FILE_SIZE_MAX));
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}
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if (key_file_offset >= (uint64_t) st.st_size)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Key file offset too large for file, refusing.");
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key_file_size = st.st_size - key_file_offset;
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}
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buffer = malloc(key_file_size);
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if (!buffer)
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return log_oom();
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if (key_file_offset > 0)
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n = pread(fd, buffer, key_file_size, key_file_offset);
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else
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n = read(fd, buffer, key_file_size);
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if (n < 0)
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return log_error_errno(errno, "Failed to read key file '%s': %m", key_file);
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if (n == 0)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Empty encrypted key found, refusing.");
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*ret_key = TAKE_PTR(buffer);
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*ret_key_size = (size_t) n;
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return 1;
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}
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