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util: introduce READ_FULL_FILE_SECURE flag for reading secure data

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This commit is contained in:
Yu Watanabe 2019-04-08 02:22:40 +09:00
parent 2432d09c7a
commit 15f8f026cf
2 changed files with 59 additions and 24 deletions
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63
src/basic/fileio.c
View File

@ -264,26 +264,27 @@ int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
return 1;
}
int read_full_stream(
int read_full_stream_full(
FILE *f,
ReadFullFileFlags flags,
char **ret_contents,
size_t *ret_size) {
_cleanup_free_ char *buf = NULL;
struct stat st;
size_t n, l;
int fd;
size_t n, n_next, l;
int fd, r;
assert(f);
assert(ret_contents);
n = LINE_MAX; /* Start size */
n_next = LINE_MAX; /* Start size */
fd = fileno(f);
if (fd >= 0) { /* If the FILE* object is backed by an fd (as opposed to memory or such, see fmemopen(), let's
* optimize our buffering) */
if (fstat(fileno(f), &st) < 0)
if (fstat(fd, &st) < 0)
return -errno;
if (S_ISREG(st.st_mode)) {
@ -296,27 +297,41 @@ int read_full_stream(
* size of 0. Note that we increase the size to read here by one, so that the first read attempt
* already makes us notice the EOF. */
if (st.st_size > 0)
n = st.st_size + 1;
n_next = st.st_size + 1;
}
}
l = 0;
n = l = 0;
for (;;) {
char *t;
size_t k;
t = realloc(buf, n + 1);
if (flags & READ_FULL_FILE_SECURE) {
t = malloc(n_next + 1);
if (!t) {
r = -ENOMEM;
goto finalize;
}
memcpy_safe(t, buf, n);
explicit_bzero_safe(buf, n);
} else {
t = realloc(buf, n_next + 1);
if (!t)
return -ENOMEM;
}
buf = t;
n = n_next;
errno = 0;
k = fread(buf + l, 1, n - l, f);
if (k > 0)
l += k;
if (ferror(f))
return errno > 0 ? -errno : -EIO;
if (ferror(f)) {
r = errno > 0 ? -errno : -EIO;
goto finalize;
}
if (feof(f))
break;
@ -327,10 +342,12 @@ int read_full_stream(
assert(l == n);
/* Safety check */
if (n >= READ_FULL_BYTES_MAX)
return -E2BIG;
if (n >= READ_FULL_BYTES_MAX) {
r = -E2BIG;
goto finalize;
}
n = MIN(n * 2, READ_FULL_BYTES_MAX);
n_next = MIN(n * 2, READ_FULL_BYTES_MAX);
}
if (!ret_size) {
@ -338,8 +355,10 @@ int read_full_stream(
* trailing NUL byte. But if there's an embedded NUL byte, then we should refuse operation as otherwise
* there'd be ambiguity about what we just read. */
if (memchr(buf, 0, l))
return -EBADMSG;
if (memchr(buf, 0, l)) {
r = -EBADMSG;
goto finalize;
}
}
buf[l] = 0;
@ -349,21 +368,27 @@ int read_full_stream(
*ret_size = l;
return 0;
finalize:
if (flags & READ_FULL_FILE_SECURE)
explicit_bzero_safe(buf, n);
return r;
}
int read_full_file(const char *fn, char **contents, size_t *size) {
int read_full_file_full(const char *filename, ReadFullFileFlags flags, char **contents, size_t *size) {
_cleanup_fclose_ FILE *f = NULL;
assert(fn);
assert(filename);
assert(contents);
f = fopen(fn, "re");
f = fopen(filename, "re");
if (!f)
return -errno;
(void) __fsetlocking(f, FSETLOCKING_BYCALLER);
return read_full_stream(f, contents, size);
return read_full_stream_full(f, flags, contents, size);
}
int executable_is_script(const char *path, char **interpreter) {

16
src/basic/fileio.h
View File

@ -27,6 +27,10 @@ typedef enum {
} WriteStringFileFlags;
typedef enum {
READ_FULL_FILE_SECURE = 1 << 0,
} ReadFullFileFlags;
int write_string_stream_ts(FILE *f, const char *line, WriteStringFileFlags flags, struct timespec *ts);
static inline int write_string_stream(FILE *f, const char *line, WriteStringFileFlags flags) {
return write_string_stream_ts(f, line, flags, NULL);
@ -38,9 +42,15 @@ static inline int write_string_file(const char *fn, const char *line, WriteStrin
int write_string_filef(const char *fn, WriteStringFileFlags flags, const char *format, ...) _printf_(3, 4);
int read_one_line_file(const char *fn, char **line);
int read_full_file(const char *fn, char **contents, size_t *size);
int read_full_stream(FILE *f, char **contents, size_t *size);
int read_one_line_file(const char *filename, char **line);
int read_full_file_full(const char *filename, ReadFullFileFlags flags, char **contents, size_t *size);
static inline int read_full_file(const char *filename, char **contents, size_t *size) {
return read_full_file_full(filename, 0, contents, size);
}
int read_full_stream_full(FILE *f, ReadFullFileFlags flags, char **contents, size_t *size);
static inline int read_full_stream(FILE *f, char **contents, size_t *size) {
return read_full_stream_full(f, 0, contents, size);
}
int verify_file(const char *fn, const char *blob, bool accept_extra_nl);