9:54 a.m.
This includes rewriting make_mapname() with dynamic memory allocation.
Suggested-by: Richard W.M. Jones <rjones(a)redhat.com>
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
options/decrypt.c | 81 +++++++++++++++-----
1 file changed, 63 insertions(+), 18 deletions(-)
diff --git a/options/decrypt.c b/options/decrypt.c
index c5b8f8f566fd..b899a0028620 100644
--- a/options/decrypt.c
+++ b/options/decrypt.c
@@ -30,6 +30,7 @@
#include <libintl.h>
#include <error.h>
#include <assert.h>
+#include <errno.h>
#include "c-ctype.h"
@@ -37,6 +38,23 @@
#include "options.h"
+static void
+append_char (size_t *idx, char *buffer, char c)
+{
+ /* bail out if the size of the string (including the terminating NUL, if any
+ * cannot be expressed as a size_t
+ */
+ if (*idx == (size_t)-1)
+ error (EXIT_FAILURE, 0, _("string size overflow"));
+
+ /* if we're not just counting, then actually write the character */
+ if (buffer != NULL)
+ buffer[*idx] = c;
+
+ /* advance */
+ ++*idx;
+}
+
/**
* Make a LUKS map name from the partition or logical volume name, eg.
* C<"/dev/vda2" =E<gt> "cryptvda2">, or
C<"/dev/vg-ssd/lv-root7" =E<gt>
@@ -44,28 +62,55 @@
* c_isalnum() eliminates the "/" separator from between the VG and the LV, so
* this mapping is not unique; but for our purposes, it will do.
*/
-static void
-make_mapname (const char *device, char *mapname, size_t len)
+static char *
+make_mapname (const char *device)
{
- size_t i = 0;
+ bool strip_iprefix;
+ static const char iprefix[] = "/dev/";
+ char *mapname;
+ enum { COUNT, WRITE, DONE } mode;
- if (len < 6)
- abort ();
- strcpy (mapname, "crypt");
- mapname += 5;
- len -= 5;
+ strip_iprefix = STRPREFIX (device, iprefix);
- if (STRPREFIX (device, "/dev/"))
- i = 5;
+ /* set to NULL in COUNT mode, flipped to non-NULL for WRITE mode */
+ mapname = NULL;
- for (; device[i] != '\0' && len >= 1; ++i) {
- if (c_isalnum (device[i])) {
- *mapname++ = device[i];
- len--;
+ for (mode = COUNT; mode < DONE; ++mode) {
+ size_t ipos;
+ static const size_t iprefixlen = sizeof iprefix - 1;
+ size_t opos;
+ static const char oprefix[] = "crypt";
+ static const size_t oprefixlen = sizeof oprefix - 1;
+ char ichar;
+
+ /* skip the input prefix, if any */
+ ipos = strip_iprefix ? iprefixlen : 0;
+ /* start producing characters after the output prefix */
+ opos = oprefixlen;
+
+ /* filter & copy */
+ while ((ichar = device[ipos]) != '\0') {
+ if (c_isalnum (ichar))
+ append_char (&opos, mapname, ichar);
+ ++ipos;
+ }
+
+ /* terminate */
+ append_char (&opos, mapname, '\0');
+
+ /* allocate the output buffer when flipping from COUNT to WRITE mode */
+ if (mode == COUNT) {
+ assert (opos >= sizeof oprefix);
+ mapname = malloc (opos);
+ if (mapname == NULL)
+ error (EXIT_FAILURE, errno, "malloc");
+
+ /* populate the output prefix -- note: not NUL-terminated yet */
+ memcpy (mapname, oprefix, oprefixlen);
}
}
- *mapname = '\0';
+ return mapname;
}
static bool
@@ -80,7 +125,7 @@ decrypt_mountables (guestfs_h *g, const char * const *mountables,
CLEANUP_FREE char *type = NULL;
CLEANUP_FREE char *uuid = NULL;
CLEANUP_FREE_STRING_LIST char **keys = NULL;
- char mapname[512];
+ CLEANUP_FREE char *mapname = NULL;
const char * const *key_scan;
const char *key;
@@ -104,8 +149,8 @@ decrypt_mountables (guestfs_h *g, const char * const *mountables,
/* Generate a node name for the plaintext (decrypted) device node. */
if (!name_decrypted_by_uuid || uuid == NULL ||
- snprintf (mapname, sizeof mapname, "luks-%s", uuid) < 0)
- make_mapname (mountable, mapname, sizeof mapname);
+ asprintf (&mapname, "luks-%s", uuid) == -1)
+ mapname = make_mapname (mountable);
/* Try each key in turn. */
key_scan = (const char * const *)keys;
--
2.19.1.3.g30247aa5d201