On 11/8/21 2:04 PM, Stephen Frost wrote:
* David Steele (da...@pgmasters.net) wrote:
I looked at trying to make this code common between the server and client
but due to the differences in error reporting it seemed like more trouble
than it was worth.
Maybe we should at least have the comments refer to each other though,
to hopefully encourage future hackers in this area to maintain
consistency between the two and avoid what happened before..?
Done.
+
+ /*
+ * Refuse to load key files owned by users other than us or root.
+ *
+ * XXX surely we can check this on Windows somehow, too.
+ */
Not really sure if there's actually much point in having this marked in
this way as it's not apparently something we're going to actually fix in
the near term. Maybe instead something like "Would be nice to find a
way to do this on Windows somehow, too, but it isn't clear today how
to."
Done.
+ /*
+ * Require no public access to key file. If the file is owned by
us,
+ * require mode 0600 or less. If owned by root, require 0640 or
less to
+ * allow read access through our gid, or a supplementary gid
that allows
+ * to read system-wide certificates.
+ *
+ * XXX temporarily suppress check when on Windows, because there
may not
+ * be proper support for Unix-y file permissions. Need to think
of a
+ * reasonable check to apply on Windows.
+ */
On the server-side, we also include a reference to postmaster.c. Not
sure if we need to do that or not but just figured I'd mention it.
Looks like this moved to miscinit.c so probably this comment deserves an
update. That might be better as a separate commit.
In the patch I referenced the function name instead since that will come
up in searches when the original function gets renamed/moved.
#ifndef WIN32
- if (!S_ISREG(buf.st_mode) || buf.st_mode & (S_IRWXG | S_IRWXO))
+ if ((buf.st_uid == geteuid() && buf.st_mode & (S_IRWXG |
S_IRWXO)) ||
+ (buf.st_uid == 0 && buf.st_mode & (S_IWGRP | S_IXGRP |
S_IRWXO)))
{
appendPQExpBuffer(&conn->errorMessage,
- libpq_gettext("private key file
\"%s\" has group or world access; permissions should be u=rw (0600) or less\n"),
+ libpq_gettext("private key file
\"%s\" has group or world access; file must have permissions u=rw (0600) or less if owned
by the current user, or permissions u=rw,g=r (0640) or less if owned by root.\n"),
fnbuf);
return -1;
}
Do we really want to remove the S_ISREG() check? We have that check
(although a bit earlier) on the server side and we've had it for a very
long time, so I don't think that we want to drop it, certainly not
without some additional discussion as to why we should (and why it would
make sense to have that be different between the client side and the
server side).
Oof. Definitely a copy-paste error.
A new version is attached with these changes, plus I consolidated the
checks under one comment block to reduce comment and #ifdef duplication.
We may want to do the same on the server side to make the code blocks
look more similar.
Also, on the server side the S_ISREG() check gets its own error and that
might be a good idea on the client side as well. As it is, the error
message on the client is going to be pretty confusing in this case.
Regards,
--
-David
da...@pgmasters.net
diff --git a/src/backend/libpq/be-secure-common.c
b/src/backend/libpq/be-secure-common.c
index a212308666..c6e4329653 100644
--- a/src/backend/libpq/be-secure-common.c
+++ b/src/backend/libpq/be-secure-common.c
@@ -155,6 +155,9 @@ check_ssl_key_file_permissions(const char *ssl_key_file,
bool isServerStart)
/*
* Refuse to load key files owned by users other than us or root.
*
+ * Note that a similar check is performed in initialize_SSL() so any
changes
+ * here may need to be made there as well.
+ *
* XXX surely we can check this on Windows somehow, too.
*/
#if !defined(WIN32) && !defined(__CYGWIN__)
@@ -174,6 +177,9 @@ check_ssl_key_file_permissions(const char *ssl_key_file,
bool isServerStart)
* allow read access through our gid, or a supplementary gid that allows
* to read system-wide certificates.
*
+ * Note that a similar check is performed in initialize_SSL() so any
changes
+ * here may need to be made there as well.
+ *
* XXX temporarily suppress check when on Windows, because there may not
* be proper support for Unix-y file permissions. Need to think of a
* reasonable check to apply on Windows. (See also the data directory
diff --git a/src/interfaces/libpq/fe-secure-openssl.c
b/src/interfaces/libpq/fe-secure-openssl.c
index a90d891c6c..d581ff6ca5 100644
--- a/src/interfaces/libpq/fe-secure-openssl.c
+++ b/src/interfaces/libpq/fe-secure-openssl.c
@@ -1240,11 +1240,37 @@ initialize_SSL(PGconn *conn)
fnbuf);
return -1;
}
+
+ /*
+ * Refuse to load key files owned by users other than us or root
and
+ * require no public access to the key file. If the file is
owned by us,
+ * require mode 0600 or less. If owned by root, require 0640 or
less to
+ * allow read access through our gid, or a supplementary gid
that allows
+ * us to read system-wide certificates.
+ *
+ * Note that similar checks are performed in
+ * check_ssl_key_file_permissions() so any changes here may need
to be
+ * made there as well.
+ *
+ * Ideally we would do similar checks on Windows but it is not
clear how
+ * that would work since unix-style permissions may not be
available. See
+ * also the data directory permissions checks in checkDataDir().
+ */
#ifndef WIN32
- if (!S_ISREG(buf.st_mode) || buf.st_mode & (S_IRWXG | S_IRWXO))
+ if (buf.st_uid != geteuid() && buf.st_uid != 0)
+ {
+ appendPQExpBuffer(&conn->errorMessage,
+
libpq_gettext("private key file \"%s\" must be owned by the current user or
root\n"),
+ fnbuf);
+ return -1;
+ }
+
+ if (!S_ISREG(buf.st_mode) ||
+ (buf.st_uid == geteuid() && buf.st_mode & (S_IRWXG |
S_IRWXO)) ||
+ (buf.st_uid == 0 && buf.st_mode & (S_IWGRP | S_IXGRP |
S_IRWXO)))
{
appendPQExpBuffer(&conn->errorMessage,
-
libpq_gettext("private key file \"%s\" has group or world access; permissions
should be u=rw (0600) or less\n"),
+
libpq_gettext("private key file \"%s\" has group or world access; file must
have permissions u=rw (0600) or less if owned by the current user, or
permissions u=rw,g=r (0640) or less if owned by root.\n"),
fnbuf);
return -1;
}
