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tmpfile-util: truncate original filename if the result filename is too long

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This also verify that the extra string does not contain '/'.
This commit is contained in:
Yu Watanabe
2022-09-03 09:47:31 +09:00
parent d8d2039c0a
commit 8ba24727c5
2 changed files with 213 additions and 73 deletions
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src/basic/tmpfile-util.c
+74 -73
View File
@@ -86,12 +86,76 @@ int fmkostemp_safe(char *pattern, const char *mode, FILE **ret_f) {
return 0;
}
int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
_cleanup_free_ char *d = NULL, *fn = NULL, *nf = NULL;
static int tempfn_build(const char *p, const char *pre, const char *post, bool child, char **ret) {
_cleanup_free_ char *d = NULL, *fn = NULL, *nf = NULL, *result = NULL;
size_t len_pre, len_post, len_add;
int r;
assert(p);
assert(ret);
/*
* Turns this:
* /foo/bar/waldo
*
* Into this :
* /foo/bar/waldo/.#<pre><post> (child == true)
* /foo/bar/.#<pre>waldo<post> (child == false)
*/
if (pre && strchr(pre, '/'))
return -EINVAL;
if (post && strchr(post, '/'))
return -EINVAL;
len_pre = strlen_ptr(pre);
len_post = strlen_ptr(post);
/* NAME_MAX is counted *without* the trailing NUL byte. */
if (len_pre > NAME_MAX - STRLEN(".#") ||
len_post > NAME_MAX - STRLEN(".#") - len_pre)
return -EINVAL;
len_add = len_pre + len_post + STRLEN(".#");
if (child) {
d = strdup(p);
if (!d)
return -ENOMEM;
} else {
r = path_extract_directory(p, &d);
if (r < 0 && r != -EDESTADDRREQ) /* EDESTADDRREQ → No directory specified, just a filename */
return r;
r = path_extract_filename(p, &fn);
if (r < 0)
return r;
if (strlen(fn) > NAME_MAX - len_add)
/* We cannot simply prepend and append strings to the filename. Let's truncate the filename. */
fn[NAME_MAX - len_add] = '\0';
}
nf = strjoin(".#", strempty(pre), strempty(fn), strempty(post));
if (!nf)
return -ENOMEM;
if (d) {
if (!path_extend(&d, nf))
return -ENOMEM;
result = path_simplify(TAKE_PTR(d));
} else
result = TAKE_PTR(nf);
if (!path_is_valid(result)) /* New path is not valid? (Maybe because too long?) Refuse. */
return -EINVAL;
*ret = TAKE_PTR(result);
return 0;
}
int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
/*
* Turns this:
* /foo/bar/waldo
@@ -100,36 +164,13 @@ int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
* /foo/bar/.#<extra>waldoXXXXXX
*/
r = path_extract_directory(p, &d);
if (r < 0 && r != -EDESTADDRREQ) /* EDESTADDRREQ → No directory specified, just a filename */
return r;
r = path_extract_filename(p, &fn);
if (r < 0)
return r;
nf = strjoin(".#", strempty(extra), fn, "XXXXXX");
if (!nf)
return -ENOMEM;
if (!filename_is_valid(nf)) /* New name is not valid? (Maybe because too long?) Refuse. */
return -EINVAL;
if (d) {
if (!path_extend(&d, nf))
return -ENOMEM;
*ret = path_simplify(TAKE_PTR(d));
} else
*ret = TAKE_PTR(nf);
return 0;
return tempfn_build(p, extra, "XXXXXX", /* child = */ false, ret);
}
int tempfn_random(const char *p, const char *extra, char **ret) {
_cleanup_free_ char *d = NULL, *fn = NULL, *nf = NULL;
int r;
_cleanup_free_ char *s = NULL;
assert(p);
assert(ret);
/*
@@ -140,37 +181,14 @@ int tempfn_random(const char *p, const char *extra, char **ret) {
* /foo/bar/.#<extra>waldobaa2a261115984a9
*/
r = path_extract_directory(p, &d);
if (r < 0 && r != -EDESTADDRREQ) /* EDESTADDRREQ → No directory specified, just a filename */
return r;
r = path_extract_filename(p, &fn);
if (r < 0)
return r;
if (asprintf(&nf, ".#%s%s%016" PRIx64,
strempty(extra),
fn,
random_u64()) < 0)
if (asprintf(&s, "%016" PRIx64, random_u64()) < 0)
return -ENOMEM;
if (!filename_is_valid(nf)) /* Not valid? (maybe because too long now?) — refuse early */
return -EINVAL;
if (d) {
if (!path_extend(&d, nf))
return -ENOMEM;
*ret = path_simplify(TAKE_PTR(d));
} else
*ret = TAKE_PTR(nf);
return 0;
return tempfn_build(p, extra, s, /* child = */ false, ret);
}
int tempfn_random_child(const char *p, const char *extra, char **ret) {
char *t, *x;
uint64_t u;
_cleanup_free_ char *s = NULL;
int r;
assert(ret);
@@ -187,27 +205,10 @@ int tempfn_random_child(const char *p, const char *extra, char **ret) {
return r;
}
extra = strempty(extra);
t = new(char, strlen(p) + 3 + strlen(extra) + 16 + 1);
if (!t)
if (asprintf(&s, "%016" PRIx64, random_u64()) < 0)
return -ENOMEM;
if (isempty(p))
x = stpcpy(stpcpy(t, ".#"), extra);
else
x = stpcpy(stpcpy(stpcpy(t, p), "/.#"), extra);
u = random_u64();
for (unsigned i = 0; i < 16; i++) {
*(x++) = hexchar(u & 0xF);
u >>= 4;
}
*x = 0;
*ret = path_simplify(t);
return 0;
return tempfn_build(p, extra, s, /* child = */ true, ret);
}
int open_tmpfile_unlinkable(const char *directory, int flags) {