Following the discussion https://github.com/shadow-maint/shadow/pull/345
I have changed the documentation to clarify the behaviour of subid
delegation when any subid source except files is configured.
Error: RESOURCE_LEAK (CWE-772): [#def31]
shadow-4.8.1/src/usermod.c:813: alloc_fn: Storage is returned from allocation function "__gr_dup".
shadow-4.8.1/src/usermod.c:813: var_assign: Assigning: "ngrp" = storage returned from "__gr_dup(grp)".
shadow-4.8.1/src/usermod.c:892: leaked_storage: Variable "ngrp" going out of scope leaks the storage it points to.
890| }
891| }
892|-> }
893|
894| #ifdef SHADOWGRP
Error: RESOURCE_LEAK (CWE-772): [#def32]
shadow-4.8.1/src/usermod.c:933: alloc_fn: Storage is returned from allocation function "__sgr_dup".
shadow-4.8.1/src/usermod.c:933: var_assign: Assigning: "nsgrp" = storage returned from "__sgr_dup(sgrp)".
shadow-4.8.1/src/usermod.c:1031: leaked_storage: Variable "nsgrp" going out of scope leaks the storage it points to.
1029| }
1030| }
1031|-> }
1032| #endif /* SHADOWGRP */
1033|
Error: RESOURCE_LEAK (CWE-772): [#def34]
shadow-4.8.1/src/usermod.c:1161: alloc_fn: Storage is returned from allocation function "getgr_nam_gid".
shadow-4.8.1/src/usermod.c:1161: var_assign: Assigning: "grp" = storage returned from "getgr_nam_gid(optarg)".
shadow-4.8.1/src/usermod.c:1495: leaked_storage: Variable "grp" going out of scope leaks the storage it points to.
1493| }
1494| #endif /* ENABLE_SUBIDS */
1495|-> }
1496|
1497| /*
Error: RESOURCE_LEAK (CWE-772): [#def35]
shadow-4.8.1/src/usermod.c:1991: open_fn: Returning handle opened by "open". [Note: The source code implementation of the function has been overridden by a user model.]
shadow-4.8.1/src/usermod.c:1991: var_assign: Assigning: "fd" = handle returned from "open("/var/log/lastlog", 2)".
shadow-4.8.1/src/usermod.c:2000: noescape: Resource "fd" is not freed or pointed-to in "lseek".
shadow-4.8.1/src/usermod.c:2000: noescape: Resource "fd" is not freed or pointed-to in "read". [Note: The source code implementation of the function has been overridden by a builtin model.]
shadow-4.8.1/src/usermod.c:2003: noescape: Resource "fd" is not freed or pointed-to in "lseek".
shadow-4.8.1/src/usermod.c:2032: leaked_handle: Handle variable "fd" going out of scope leaks the handle.
2030| }
2031| }
2032|-> }
2033|
2034| /*
Error: RESOURCE_LEAK (CWE-772): [#def36]
shadow-4.8.1/src/usermod.c:2052: open_fn: Returning handle opened by "open". [Note: The source code implementation of the function has been overridden by a user model.]
shadow-4.8.1/src/usermod.c:2052: var_assign: Assigning: "fd" = handle returned from "open("/var/log/faillog", 2)".
shadow-4.8.1/src/usermod.c:2061: noescape: Resource "fd" is not freed or pointed-to in "lseek".
shadow-4.8.1/src/usermod.c:2061: noescape: Resource "fd" is not freed or pointed-to in "read". [Note: The source code implementation of the function has been overridden by a builtin model.]
shadow-4.8.1/src/usermod.c:2064: noescape: Resource "fd" is not freed or pointed-to in "lseek".
shadow-4.8.1/src/usermod.c:2092: leaked_handle: Handle variable "fd" going out of scope leaks the handle.
2090| }
2091| }
2092|-> }
2093|
2094| #ifndef NO_MOVE_MAILBOX
Clarify that the subid delegation can only come from one source.
Moreover, add an example of what might happen if the subid source is NSS
and useradd is executed.
Related: https://github.com/shadow-maint/shadow/issues/331
Closes#331
1. drop 'has_any_range' nss method as it is not useful
2. do not try to create a subid range in newusers when using nss for
subids, since that's not possible.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
(cherry picked from commit 88a434adbdcf4a8640793fd58bcd2ba77598349d)
Following alexey-tikhonov's suggestion.
Since we've dropped the 'owner' field in the data returned for
get_subid_ranges, we can just return a single allocated array of
simple structs. This means we can return a ** instead of ***, and
we can get rid of the subid_free_ranges() helper, since the caller
can just free() the returned data.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
The rest of the run isn't likely to get much better, is it?
Thanks to Alexey for pointing this out.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Cc: Alexey Tikhonov <atikhono@redhat.com>
Closes: 339
struct subordinate_range is pretty closely tied to the existing
subid code and /etc/subuid format, so it includes an owner. Dropping
that or even renaming it is more painful than I'd first thought.
So introduce a 'struct subid_range' which is only the start and
count, leaving 'struct subordinate_range' as the owner, start and
count.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Closes#325
Add a new subid_init() function which can be used to specify the
stream on which error messages should be printed. (If you want to
get fancy you can redirect that to memory :) If subid_init() is
not called, use stderr. If NULL is passed, then /dev/null will
be used.
This patch also fixes up the 'Prog', which previously had to be
defined by any program linking against libsubid. Now, by default
in libsubid it will show (subid). Once subid_init() is called,
it will use the first variable passed to subid_init().
Signed-off-by: Serge Hallyn <serge@hallyn.com>
When uid 0 maps host uid 0 into the child userns newer kernels require
CAP_SETFCAP be retained as this allows the caller to create fscaps that
are valid in the ancestor userns. This was a security issue (in very
rare circumstances). So whenever host uid 0 is mapped, retain
CAP_SETFCAP if the caller had it.
Userspace won't need to set CAP_SETFCAP on newuidmap as this is really
only a scenario that real root should be doing which always has
CAP_SETFCAP. And if they don't then they are in a locked-down userns.
(LXC sometimes maps host uid 0 during chown operations in a helper
userns but will not rely on newuidmap for that. But we don't want to
risk regressing callers that want to rely on this behavior.)
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Include the new HMAC_CRYPTO_ALGO key that is needed by pam_timestamp to
select the algorithm that is going to be used to calculate the message
authentication code.
pam_timestamp is currently using an embedded algorithm to calculate the
HMAC message, but the idea is to improve this behaviour by relying on
openssl's implementation. On top of that, the ability to change the
algorithm with a simple configuration change allows to simplify the
process of removing unsecure algorithms.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1947294
Once opened, keep the selabel database open for further lookups.
Register an exit handler to close the database.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
Search the SELinux selabel database for the file type to be created.
Not specifying the file mode can cause an incorrect file context to be
returned.
Also prepare contexts in commonio_close() for the generic database
filename, not with the backup suffix appended, to ensure the desired
file context after the final rename.
Closes: #322
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
matchpathcon(3) is deprecated in favor of selabel_lookup(3).
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
Return 0 on setfscreatecon(3) failure, like set_selinux_file_context().
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
These retrieved contexts are just passed to libselinux functions and not
printed or otherwise made available to the outside, so a context
translation to human readable MCS/MLS labels is not needed.
(see man:setrans.conf(5))
The typedef security_context_t is deprecated, see
9eb9c93275
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
This retrieved context is just passed to libselinux functions and not
printed or otherwise made available to the outside, so a context
translation to human readable MCS/MLS labels is not needed.
(see man:setrans.conf(5))
The typedef security_context_t is deprecated, see
9eb9c93275
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
The typedef security_context_t is deprecated, see
9eb9c93275
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
Currently, supplying a relative path via the --prefix flag to the
useradd command triggers a bug in the creation of home directories. The
code seems to unintentionally prepend a leading "/" to all paths,
quietly transforming a relative prefixed home path into an absolute
path. This can be seen in the following strace logs from running
"useradd --create-home --prefix tmp/root squat":
```
access("tmp/root//home/squat", F_OK) = -1 ENOENT (No such file or directory)
access("/mp", F_OK) = 0
access("/mp/root", F_OK) = 0
access("/mp/root/home", F_OK) = 0
access("/mp/root/home/squat", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/mp/root/home/squat", 000) = 0
chown("/mp/root/home/squat", 0, 0) = 0
chmod("/mp/root/home/squat", 0755) = 0
chown("tmp/root//home/squat", 1000, 1000) = -1 ENOENT (No such file or directory)
chmod("tmp/root//home/squat", 0700) = -1 ENOENT (No such file or directory)
```
Note that the relative path is correctly probed in the beginning and it
is only during the recursive creation that the path is turned into an
absolute path. This invocation results in the creation of a "/mp"
hierarchy in the root of the filesystem.
Similar problems occur when using `--prefix ./tmp/root`.
This commit fixes the handling of relative paths by not assuming that
the given path is anchored with a "/".
Signed-off-by: Lucas Servén Marín <lserven@gmail.com>
Otherwise our su -p uses bash if that is what root was
configured to use, and then fails to read /root/ for
.bash_profile. This caused an unexpected error message
in /tmp/err, failing the test.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Closes#154
When starting any operation to do with subuid delegation, check
nsswitch for a module to use. If none is specified, then use
the traditional /etc/subuid and /etc/subgid files.
Currently only one module is supported, and there is no fallback
to the files on errors. Several possibilities could be considered:
1. in case of connection error, fall back to files
2. in case of unknown user, also fall back to files
etc...
When non-files nss module is used, functions to edit the range
are not supported. It may make sense to support it, but it also
may make sense to require another tool to be used.
libsubordinateio also uses the nss_ helpers. This is how for instance
lxc could easily be converted to supporting nsswitch.
Add a set of test cases, including a dummy libsubid_zzz module. This
hardcodes values such that:
'ubuntu' gets 200000 - 300000
'user1' gets 100000 - 165536
'error' emulates an nss module error
'unknown' emulates a user unknown to the nss module
'conn' emulates a connection error ot the nss module
Changes to libsubid:
Change the list_owner_ranges api: return a count instead of making the array
null terminated.
This is a breaking change, so bump the libsubid abi major number.
Rename free_subuid_range and free_subgid_range to ungrant_subuid_range,
because otherwise it's confusing with free_subid_ranges which frees
memory.
Run libsubid tests in jenkins
Switch argument order in find_subid_owners
Move the db locking into subordinateio.c
Signed-off-by: Serge Hallyn <serge@hallyn.com>
