user/sven/linux.git/security, branch v5.7.10

apparmor: ensure that dfa state tables have entries

2020-07-22T07:34:12Z

commit c27c6bd2c4d6b6bb779f9b722d5607993e1d5e5c upstream. Currently it is possible to specify a state machine table with 0 length, this is not valid as optional tables are specified by not defining the table as present. Further this allows by-passing the base tables range check against the next/check tables. Fixes: d901d6a298dc ("apparmor: dfa split verification of table headers") Reported-by: Mike Salvatore Signed-off-by: John Johansen Signed-off-by: Greg Kroah-Hartman

security: Fix hook iteration and default value for inode_copy_up_xattr

2020-07-09T07:39:33Z

[ Upstream commit 23e390cdbe6f85827a43d38f9288dcd3066fa376 ] inode_copy_up_xattr returns 0 to indicate the acceptance of the xattr and 1 to reject it. If the LSM does not know about the xattr, it's expected to return -EOPNOTSUPP, which is the correct default value for this hook. BPF LSM, currently, uses 0 as the default value and thereby falsely allows all overlay fs xattributes to be copied up. The iteration logic is also updated from the "bail-on-fail" call_int_hook to continue on the non-decisive -EOPNOTSUPP and bail out on other values. Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Signed-off-by: KP Singh Signed-off-by: James Morris Signed-off-by: Sasha Levin

selinux: fix undefined return of cond_evaluate_expr

2020-06-24T15:49:19Z

commit 8231b0b9c322c894594fb42eb0eb9f93544a6acc upstream. clang static analysis reports an undefined return security/selinux/ss/conditional.c:79:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn] return s[0]; ^~~~~~~~~~~ static int cond_evaluate_expr( ... { u32 i; int s[COND_EXPR_MAXDEPTH]; for (i = 0; i < expr->len; i++) ... return s[0]; When expr->len is 0, the loop which sets s[0] never runs. So return -1 if the loop never runs. Cc: stable@vger.kernel.org Signed-off-by: Tom Rix Acked-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

selinux: fix a double free in cond_read_node()/cond_read_list()

2020-06-24T15:49:19Z

commit aa449a7965a6172a89d48844c313708962216f1f upstream. Clang static analysis reports this double free error security/selinux/ss/conditional.c:139:2: warning: Attempt to free released memory [unix.Malloc] kfree(node->expr.nodes); ^~~~~~~~~~~~~~~~~~~~~~~ When cond_read_node fails, it calls cond_node_destroy which frees the node but does not poison the entry in the node list. So when it returns to its caller cond_read_list, cond_read_list deletes the partial list. The latest entry in the list will be deleted twice. So instead of freeing the node in cond_read_node, let list freeing in code_read_list handle the freeing the problem node along with all of the earlier nodes. Because cond_read_node no longer does any error handling, the goto's the error case are redundant. Instead just return the error code. Cc: stable@vger.kernel.org Fixes: 60abd3181db2 ("selinux: convert cond_list to array") Signed-off-by: Tom Rix Reviewed-by: Ondrej Mosnacek [PM: subject line tweaks] Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

selinux: fix double free

2020-06-24T15:49:19Z

commit 65de50969a77509452ae590e9449b70a22b923bb upstream. Clang's static analysis tool reports these double free memory errors. security/selinux/ss/services.c:2987:4: warning: Attempt to free released memory [unix.Malloc] kfree(bnames[i]); ^~~~~~~~~~~~~~~~ security/selinux/ss/services.c:2990:2: warning: Attempt to free released memory [unix.Malloc] kfree(bvalues); ^~~~~~~~~~~~~~ So improve the security_get_bools error handling by freeing these variables and setting their return pointers to NULL and the return len to 0 Cc: stable@vger.kernel.org Signed-off-by: Tom Rix Acked-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

apparmor: fix nnp subset test for unconfined

2020-06-24T15:48:32Z

[ Upstream commit 3ed4aaa94fc07db3cd0c91be95e3e1b9782a2710 ] The subset test is not taking into account the unconfined exception which will cause profile transitions in the stacked confinement case to fail when no_new_privs is applied. This fixes a regression introduced in the fix for https://bugs.launchpad.net/bugs/1839037 BugLink: https://bugs.launchpad.net/bugs/1844186 Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: check/put label on apparmor_sk_clone_security()

2020-06-24T15:48:31Z

[ Upstream commit 3b646abc5bc6c0df649daea4c2c976bd4d47e4c8 ] Currently apparmor_sk_clone_security() does not check for existing label/peer in the 'new' struct sock; it just overwrites it, if any (with another reference to the label of the source sock.) static void apparmor_sk_clone_security(const struct sock *sk, struct sock *newsk) { struct aa_sk_ctx *ctx = SK_CTX(sk); struct aa_sk_ctx *new = SK_CTX(newsk); new->label = aa_get_label(ctx->label); new->peer = aa_get_label(ctx->peer); } This might leak label references, which might overflow under load. Thus, check for and put labels, to prevent such errors. Note this is similarly done on: static int apparmor_socket_post_create(struct socket *sock, ...) ... if (sock->sk) { struct aa_sk_ctx *ctx = SK_CTX(sock->sk); aa_put_label(ctx->label); ctx->label = aa_get_label(label); } ... Context: ------- The label reference count leak is observed if apparmor_sock_graft() is called previously: this sets the 'ctx->label' field by getting a reference to the current label (later overwritten, without put.) static void apparmor_sock_graft(struct sock *sk, ...) { struct aa_sk_ctx *ctx = SK_CTX(sk); if (!ctx->label) ctx->label = aa_get_current_label(); } And that is the case on crypto/af_alg.c:af_alg_accept(): int af_alg_accept(struct sock *sk, struct socket *newsock, ...) ... struct sock *sk2; ... sk2 = sk_alloc(...); ... security_sock_graft(sk2, newsock); security_sk_clone(sk, sk2); ... Apparently both calls are done on their own right, especially for other LSMs, being introduced in 2010/2014, before apparmor socket mediation in 2017 (see commits [1,2,3,4]). So, it looks OK there! Let's fix the reference leak in apparmor. Test-case: --------- Exercise that code path enough to overflow label reference count. $ cat aa-refcnt-af_alg.c #include #include #include #include #include int main() { int sockfd; struct sockaddr_alg sa; /* Setup the crypto API socket */ sockfd = socket(AF_ALG, SOCK_SEQPACKET, 0); if (sockfd < 0) { perror("socket"); return 1; } memset(&sa, 0, sizeof(sa)); sa.salg_family = AF_ALG; strcpy((char *) sa.salg_type, "rng"); strcpy((char *) sa.salg_name, "stdrng"); if (bind(sockfd, (struct sockaddr *) &sa, sizeof(sa)) < 0) { perror("bind"); return 1; } /* Accept a "connection" and close it; repeat. */ while (!close(accept(sockfd, NULL, 0))); return 0; } $ gcc -o aa-refcnt-af_alg aa-refcnt-af_alg.c $ ./aa-refcnt-af_alg [ 9928.475953] refcount_t overflow at apparmor_sk_clone_security+0x37/0x70 in aa-refcnt-af_alg[1322], uid/euid: 1000/1000 ... [ 9928.507443] RIP: 0010:apparmor_sk_clone_security+0x37/0x70 ... [ 9928.514286] security_sk_clone+0x33/0x50 [ 9928.514807] af_alg_accept+0x81/0x1c0 [af_alg] [ 9928.516091] alg_accept+0x15/0x20 [af_alg] [ 9928.516682] SYSC_accept4+0xff/0x210 [ 9928.519609] SyS_accept+0x10/0x20 [ 9928.520190] do_syscall_64+0x73/0x130 [ 9928.520808] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Note that other messages may be seen, not just overflow, depending on the value being incremented by kref_get(); on another run: [ 7273.182666] refcount_t: saturated; leaking memory. ... [ 7273.185789] refcount_t: underflow; use-after-free. Kprobes: ------- Using kprobe events to monitor sk -> sk_security -> label -> count (kref): Original v5.7 (one reference leak every iteration) ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd2 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd4 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd3 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd5 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd4 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd6 Patched v5.7 (zero reference leak per iteration) ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594 Commits: ------- [1] commit 507cad355fc9 ("crypto: af_alg - Make sure sk_security is initialized on accept()ed sockets") [2] commit 4c63f83c2c2e ("crypto: af_alg - properly label AF_ALG socket") [3] commit 2acce6aa9f65 ("Networking") a.k.a ("crypto: af_alg - Avoid sock_graft call warning) [4] commit 56974a6fcfef ("apparmor: add base infastructure for socket mediation") Fixes: 56974a6fcfef ("apparmor: add base infastructure for socket mediation") Reported-by: Brian Moyles Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: fix introspection of of task mode for unconfined tasks

2020-06-24T15:48:30Z

[ Upstream commit dd2569fbb053719f7df7ef8fdbb45cf47156a701 ] Fix two issues with introspecting the task mode. 1. If a task is attached to a unconfined profile that is not the ns->unconfined profile then. Mode the mode is always reported as - $ ps -Z LABEL PID TTY TIME CMD unconfined 1287 pts/0 00:00:01 bash test (-) 1892 pts/0 00:00:00 ps instead of the correct value of (unconfined) as shown below $ ps -Z LABEL PID TTY TIME CMD unconfined 2483 pts/0 00:00:01 bash test (unconfined) 3591 pts/0 00:00:00 ps 2. if a task is confined by a stack of profiles that are unconfined the output of label mode is again the incorrect value of (-) like above, instead of (unconfined). This is because the visibile profile count increment is skipped by the special casing of unconfined. Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels") Signed-off-by: John Johansen Signed-off-by: Sasha Levin

ima: Set again build_ima_appraise variable

2020-06-22T07:33:00Z

[ Upstream commit b59fda449cf07f2db3be3a67142e6c000f5e8d79 ] After adding the new add_rule() function in commit c52657d93b05 ("ima: refactor ima_init_policy()"), all appraisal flags are added to the temp_ima_appraise variable. Revert to the previous behavior instead of removing build_ima_appraise, to benefit from the protection offered by __ro_after_init. The mentioned commit introduced a bug, as it makes all the flags modifiable, while build_ima_appraise flags can be protected with __ro_after_init. Cc: stable@vger.kernel.org # 5.0.x Fixes: c52657d93b05 ("ima: refactor ima_init_policy()") Co-developed-by: Roberto Sassu Signed-off-by: Roberto Sassu Signed-off-by: Krzysztof Struczynski Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin

ima: Remove redundant policy rule set in add_rules()

2020-06-22T07:32:59Z

[ Upstream commit 6ee28442a465ab4c4be45e3b15015af24b1ba906 ] Function ima_appraise_flag() returns the flag to be set in temp_ima_appraise depending on the hook identifier passed as an argument. It is not necessary to set the flag again for the POLICY_CHECK hook. Signed-off-by: Krzysztof Struczynski Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin