64 lines
2.3 KiB
Diff
64 lines
2.3 KiB
Diff
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This patch is from Slackware, I tried to find the actual
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author to add that attribution. The comment below is the
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best summary, I will not repeat it here.
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Upstream-Status: Backport from slackware
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Signed-off-by: Saul Wold <sgw@linux.intel.com>
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Index: shadow-4.1.4.3/lib/encrypt.c
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===================================================================
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--- shadow-4.1.4.3.orig/lib/encrypt.c
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+++ shadow-4.1.4.3/lib/encrypt.c
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@@ -45,15 +45,40 @@ char *pw_encrypt (const char *clear, con
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static char cipher[128];
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char *cp;
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- cp = crypt (clear, salt);
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- if (!cp) {
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- /*
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- * Single Unix Spec: crypt() may return a null pointer,
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- * and set errno to indicate an error. The caller doesn't
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- * expect us to return NULL, so...
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- */
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- perror ("crypt");
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- exit (EXIT_FAILURE);
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+ cp = crypt (clear, salt);
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+ if (!cp) {
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+ /*
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+ * In glibc-2.17 and newer, crypt() will return NULL if
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+ * it was called using an invalid salt format. Previous
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+ * versions of glibc would go ahead and compute a DES hash
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+ * using the invalid salt. The salt value in this case was
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+ * always '!'. We might arrive at this place if either the
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+ * user does not exist, or if the hash in /etc/shadow doesn't
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+ * have the proper magic for one of the supported hash
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+ * formats (for example, if the account was locked using
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+ * "passwd -l". To handle this situation, we will recompute
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+ * the hash using a hardcoded salt as was previously done
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+ * by glibc. The hash returned by the old glibc function
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+ * always began with "!!", which would ensure that it could
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+ * never match an otherwise valid hash in /etc/shadow that
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+ * was disabled with a "!" at the beginning (since the second
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+ * character would never be "!" as well), so we will also
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+ * prepend the resulting hash with "!!". Finally, in case
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+ * crypt() failed for some other reason we will check to see
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+ * if we still get NULL from crypt even with the valid salt
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+ * and will fail if that's the case.
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+ */
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+
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+ /* Recalculate hash using a hardcoded, valid SHA512 salt: */
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+ cp = crypt (clear, "$6$8IIcy/1EPOk/");
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+
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+ if (!cp) {
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+ perror ("crypt");
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+ exit (EXIT_FAILURE);
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+ } else {
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+ sprintf (cipher, "!!%s", cp);
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+ return cipher;
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+ }
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}
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/* The GNU crypt does not return NULL if the algorithm is not
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