[PATCH 1/6] iconv: Remove alloca use in gconv-modules configuration parsing
Siddhesh Poyarekar
siddhesh@sourceware.org
Thu Jun 10 11:18:48 GMT 2021
The alloca sizes ought to be constrained to PATH_MAX, but replace them
with dynamic allocation to be safe. A static PATH_MAX array would
have worked too but Hurd does not have PATH_MAX and the code path is
not hot enough to micro-optimise this allocation. Revisit if any of
those realities change.
---
iconv/gconv_conf.c | 17 +++++++++--------
iconv/iconvconfig.c | 17 +++++++++++------
2 files changed, 20 insertions(+), 14 deletions(-)
diff --git a/iconv/gconv_conf.c b/iconv/gconv_conf.c
index c8ad8099a4..3f2cef255b 100644
--- a/iconv/gconv_conf.c
+++ b/iconv/gconv_conf.c
@@ -559,15 +559,15 @@ __gconv_read_conf (void)
for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
{
-#define BUF_LEN elem_len + sizeof (gconv_conf_dirname)
-
const char *elem = __gconv_path_elem[cnt].name;
size_t elem_len = __gconv_path_elem[cnt].len;
- char *buf;
/* No slash needs to be inserted between elem and gconv_conf_filename;
elem already ends in a slash. */
- buf = alloca (BUF_LEN);
+ char *buf = malloc (elem_len + sizeof (gconv_conf_dirname));
+ if (buf == NULL)
+ continue;
+
char *cp = __mempcpy (__mempcpy (buf, elem, elem_len),
gconv_conf_filename, sizeof (gconv_conf_filename));
@@ -596,15 +596,16 @@ __gconv_read_conf (void)
if (len > strlen (suffix)
&& strcmp (ent->d_name + len - strlen (suffix), suffix) == 0)
{
- /* LEN <= PATH_MAX so this alloca is not unbounded. */
- char *conf = alloca (BUF_LEN + len + 1);
- cp = stpcpy (conf, buf);
- sprintf (cp, "/%s", ent->d_name);
+ char *conf;
+ if (__asprintf (&conf, "%s/%s", buf, ent->d_name) < 0)
+ continue;
read_conf_file (conf, elem, elem_len, &modules, &nmodules);
+ free (conf);
}
}
__closedir (confdir);
}
+ free (buf);
}
#endif
diff --git a/iconv/iconvconfig.c b/iconv/iconvconfig.c
index b2a868919c..c9607fb645 100644
--- a/iconv/iconvconfig.c
+++ b/iconv/iconvconfig.c
@@ -712,7 +712,6 @@ handle_file (const char *dir, const char *infile)
static int
handle_dir (const char *dir)
{
-#define BUF_LEN prefix_len + dirlen + sizeof "gconv-modules.d"
char *cp;
size_t dirlen = strlen (dir);
bool found = false;
@@ -726,7 +725,10 @@ handle_dir (const char *dir)
}
/* First, look for a gconv-modules file. */
- char buf[BUF_LEN];
+ char *buf = malloc (prefix_len + dirlen + sizeof "gconv-modules.d");
+ if (buf == NULL)
+ goto out;
+
cp = buf;
if (dir[0] == '/')
cp = mempcpy (cp, prefix, prefix_len);
@@ -756,16 +758,19 @@ handle_dir (const char *dir)
if (len > strlen (suffix)
&& strcmp (ent->d_name + len - strlen (suffix), suffix) == 0)
{
- /* LEN <= PATH_MAX so this alloca is not unbounded. */
- char *conf = alloca (BUF_LEN + len + 1);
- cp = stpcpy (conf, buf);
- sprintf (cp, "/%s", ent->d_name);
+ char *conf;
+ if (asprintf (&conf, "%s/%s", buf, ent->d_name) < 0)
+ continue;
found |= handle_file (dir, conf);
+ free (conf);
}
}
closedir (confdir);
}
+ free (buf);
+
+out:
if (!found)
{
error (0, errno, "failed to open gconv configuration files in `%s'",
--
2.31.1
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