| 1 | |
| 2 | |
| 3 | * Landlock - Credential hooks
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| 4 | *
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| 5 | * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
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| 6 | * Copyright © 2018-2020 ANSSI
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| 7 | * Copyright © 2024-2025 Microsoft Corporation
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| 8 |
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| 9 |
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| 10 | #include <linux/binfmts.h>
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| 11 | #include <linux/cred.h>
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| 12 | #include <linux/lsm_hooks.h>
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| 13 |
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| 14 | #include "common.h"
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| 15 | #include "cred.h"
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| 16 | #include "ruleset.h"
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| 17 | #include "setup.h"
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| 18 |
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| 19 | static void hook_cred_transfer(struct cred *const new,
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| 20 | const struct cred *const old)
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| 21 | {
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| 22 | const struct landlock_cred_security *const old_llcred =
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| 23 | landlock_cred(old);
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| 24 |
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| 25 | landlock_get_domain(old_llcred->domain);
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| 26 | *landlock_cred(new) = *old_llcred;
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| 27 | }
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| 28 |
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| 29 | static int hook_cred_prepare(struct cred *const new,
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| 30 | const struct cred *const old, const gfp_t gfp)
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| 31 | {
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| 32 | hook_cred_transfer(new, old);
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| 33 | return 0;
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| 34 | }
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| 35 |
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| 36 | static void hook_cred_free(struct cred *const cred)
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| 37 | {
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| 38 | struct landlock_domain *const dom = landlock_cred(cred)->domain;
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| 39 |
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| 40 | if (dom)
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| 41 | landlock_put_domain_deferred(dom);
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| 42 | }
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| 43 |
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| 44 | #ifdef CONFIG_SECURITY_LANDLOCK_LOG
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| 45 |
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| 46 | static int hook_bprm_creds_for_exec(struct linux_binprm *const bprm)
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| 47 | {
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| 48 |
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| 49 | landlock_cred(bprm->cred)->domain_exec = 0;
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| 50 | return 0;
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| 51 | }
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| 52 |
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| 53 | #endif
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| 54 |
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| 55 | static struct security_hook_list landlock_hooks[] __ro_after_init = {
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| 56 | LSM_HOOK_INIT(cred_prepare, hook_cred_prepare),
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| 57 | LSM_HOOK_INIT(cred_transfer, hook_cred_transfer),
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| 58 | LSM_HOOK_INIT(cred_free, hook_cred_free),
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| 59 |
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| 60 | #ifdef CONFIG_SECURITY_LANDLOCK_LOG
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| 61 | LSM_HOOK_INIT(bprm_creds_for_exec, hook_bprm_creds_for_exec),
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| 62 | #endif
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| 63 | };
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| 64 |
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| 65 | __init void landlock_add_cred_hooks(void)
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| 66 | {
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| 67 | security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
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| 68 | &landlock_lsmid);
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| 69 | }
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