Using the random() function to obtain pseudo-random bytes
for generating salt strings is considered to be dangerous.
See CWE-327.
We really should use a more reliable source for obtaining
pseudo-random bytes like /dev/urandom.
Fixes#376.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
In the previous commit we refactored the functions converting the
rounds number into a string for use with the crypt() function, to
not require any static buffer anymore.
Add some clarifying comments about how the minimum required buffer
length is computed inside of these functions.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
* Move all pre-processor defines to the top of the file.
* Unify the gensalt() function to be useable for all supported
hash methods.
* Drop the gensalt_{b,yes}crypt() functions in favor of the
previous change.
* Refactor the functions converting the rounds number into
a string for use with the crypt() function, to not require
any static buffer anymore.
* Clarify the comment about how crypt_make_salt() chooses the used
hash method from the settings in the login.defs file.
* Use memset() to fill static buffers with zero before using them.
* Use a fixed amount of 16 random base64-chars for the
sha{256,512}crypt hash methods, which is effectively still less
than the recommendation from NIST (>= 128 bits), but the maximum
those methods can effectively use (approx. 90 bits).
* Rename ROUNDS_{MIN,MAX} to SHA_ROUNDS_{MIN,MAX}.
* Bugfixes in the logic of setting rounds in BCRYPT_salt_rounds().
* Likewise for YESCRYPT_salt_cost().
* Fix formatting and white-space errors.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
The corresponding functions for the other hash methods all take
a pointer to an integer value as the only paramater, so this
particular function should do so as well.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
Error: RESOURCE_LEAK (CWE-772): [#def28]
shadow-4.8.1/src/useradd.c:1905: 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/useradd.c:1905: var_assign: Assigning: "fd" = handle returned from "open("/var/log/faillog", 2)".
shadow-4.8.1/src/useradd.c:1906: noescape: Resource "fd" is not freed or pointed-to in "lseek".
shadow-4.8.1/src/useradd.c:1917: leaked_handle: Handle variable "fd" going out of scope leaks the handle.
1915| /* continue */
1916| }
1917|-> }
1918|
1919| static void lastlog_reset (uid_t uid)
Error: RESOURCE_LEAK (CWE-772): [#def29]
shadow-4.8.1/src/useradd.c:1938: 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/useradd.c:1938: var_assign: Assigning: "fd" = handle returned from "open("/var/log/lastlog", 2)".
shadow-4.8.1/src/useradd.c:1939: noescape: Resource "fd" is not freed or pointed-to in "lseek".
shadow-4.8.1/src/useradd.c:1950: leaked_handle: Handle variable "fd" going out of scope leaks the handle.
1948| /* continue */
1949| }
1950|-> }
1951|
1952| static void tallylog_reset (const char *user_name)
Error: RESOURCE_LEAK (CWE-772): [#def30]
shadow-4.8.1/src/useradd.c:2109: alloc_fn: Storage is returned from allocation function "strdup".
shadow-4.8.1/src/useradd.c:2109: var_assign: Assigning: "bhome" = storage returned from "strdup(prefix_user_home)".
shadow-4.8.1/src/useradd.c:2131: noescape: Resource "bhome" is not freed or pointed-to in "strtok".
shadow-4.8.1/src/useradd.c:2207: leaked_storage: Variable "bhome" going out of scope leaks the storage it points to.
2205| }
2206| #endif
2207|-> }
2208| }
2209|
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>
