On Mon, 2024-06-24 at 18:47 +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > The patch below does not apply to the 6.6-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <stable@xxxxxxxxxxxxxxx>. > > To reproduce the conflict and resubmit, you may use the following commands: > > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y > git checkout FETCH_HEAD > git cherry-pick -x 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 > # <resolve conflicts, build, test, etc.> > git commit -s > git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2024062438-shaft-herbicide-4e7d@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. > > Possible dependencies: > > 9a95c5bfbf02 ("ima: Avoid blocking in RCU read-side critical section") > 260017f31a8c ("lsm: use default hook return value in call_int_hook()") > 923831117611 ("evm: Move to LSM infrastructure") > 84594c9ecdca ("ima: Move IMA-Appraisal to LSM infrastructure") > cd3cec0a02c7 ("ima: Move to LSM infrastructure") > 06cca5110774 ("integrity: Move integrity_kernel_module_request() to IMA") > b8d997032a46 ("security: Introduce key_post_create_or_update hook") > 2d705d802414 ("security: Introduce inode_post_remove_acl hook") > 8b9d0b825c65 ("security: Introduce inode_post_set_acl hook") > a7811e34d100 ("security: Introduce inode_post_create_tmpfile hook") > f09068b5a114 ("security: Introduce file_release hook") > 8f46ff5767b0 ("security: Introduce file_post_open hook") > dae52cbf5887 ("security: Introduce inode_post_removexattr hook") > 77fa6f314f03 ("security: Introduce inode_post_setattr hook") > 314a8dc728d0 ("security: Align inode_setattr hook definition with EVM") > 779cb1947e27 ("evm: Align evm_inode_post_setxattr() definition with LSM infrastructure") > 2b6a4054f8c2 ("evm: Align evm_inode_setxattr() definition with LSM infrastructure") > 784111d0093e ("evm: Align evm_inode_post_setattr() definition with LSM infrastructure") > fec5f85e468d ("ima: Align ima_post_read_file() definition with LSM infrastructure") > 526864dd2f60 ("ima: Align ima_inode_removexattr() definition with LSM infrastructure") The patch doesn't apply cleanly due to the '0' in security_audit_rule_init(): return call_int_hook(audit_rule_init, 0, field, op, rulestr, lsmrule); Commit 260017f31a8c ("lsm: use default hook return value in call_int_hook()") removed it. Instead of backporting commit 260017f31a8c, adding the '0' would be simpler. This seems to be the only change needed for linux-6.8.y to 6.4.y. For linux-6.3.y to linux-6.2.y, commit b14faf9c94a6 ("lsm: move the audit hook comments to security/security.c") also needs to be applied. Paul, how do you normally handle backports? > thanks, > > greg k-h > > ------------------ original commit in Linus's tree ------------------ > > From 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 Mon Sep 17 00:00:00 2001 > From: GUO Zihua <guozihua@xxxxxxxxxx> > Date: Tue, 7 May 2024 01:25:41 +0000 > Subject: [PATCH] ima: Avoid blocking in RCU read-side critical section > > A panic happens in ima_match_policy: > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 > PGD 42f873067 P4D 0 > Oops: 0000 [#1] SMP NOPTI > CPU: 5 PID: 1286325 Comm: kubeletmonit.sh > Kdump: loaded Tainted: P > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), > BIOS 0.0.0 02/06/2015 > RIP: 0010:ima_match_policy+0x84/0x450 > Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39 > 7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d > f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea > 44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f > RSP: 0018:ff71570009e07a80 EFLAGS: 00010207 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200 > RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000 > RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739 > R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970 > R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001 > FS: 00007f5195b51740(0000) > GS:ff3e278b12d40000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > ima_get_action+0x22/0x30 > process_measurement+0xb0/0x830 > ? page_add_file_rmap+0x15/0x170 > ? alloc_set_pte+0x269/0x4c0 > ? prep_new_page+0x81/0x140 > ? simple_xattr_get+0x75/0xa0 > ? selinux_file_open+0x9d/0xf0 > ima_file_check+0x64/0x90 > path_openat+0x571/0x1720 > do_filp_open+0x9b/0x110 > ? page_counter_try_charge+0x57/0xc0 > ? files_cgroup_alloc_fd+0x38/0x60 > ? __alloc_fd+0xd4/0x250 > ? do_sys_open+0x1bd/0x250 > do_sys_open+0x1bd/0x250 > do_syscall_64+0x5d/0x1d0 > entry_SYSCALL_64_after_hwframe+0x65/0xca > > Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by > ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a > RCU read-side critical section which contains kmalloc with GFP_KERNEL. > This implies a possible sleep and violates limitations of RCU read-side > critical sections on non-PREEMPT systems. > > Sleeping within RCU read-side critical section might cause > synchronize_rcu() returning early and break RCU protection, allowing a > UAF to happen. > > The root cause of this issue could be described as follows: > > Thread A | Thread B | > > |ima_match_policy | > > | rcu_read_lock | > > ima_lsm_update_rule | | > > synchronize_rcu | | > > | kmalloc(GFP_KERNEL)| > > | sleep | > ==> synchronize_rcu returns early > > kfree(entry) | | > > | entry = entry->next| > ==> UAF happens and entry now becomes NULL (or could be anything). > > | entry->action | > ==> Accessing entry might cause panic. > > To fix this issue, we are converting all kmalloc that is called within > RCU read-side critical section to use GFP_ATOMIC. > > Fixes: c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()") > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: GUO Zihua <guozihua@xxxxxxxxxx> > Acked-by: John Johansen <john.johansen@xxxxxxxxxxxxx> > Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx> > Reviewed-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx> > [PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case] > Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx> > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index f804b76cde44..44488b1ab9a9 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -413,7 +413,7 @@ LSM_HOOK(void, LSM_RET_VOID, key_post_create_or_update, struct key *keyring, > > #ifdef CONFIG_AUDIT > LSM_HOOK(int, 0, audit_rule_init, u32 field, u32 op, char *rulestr, > - void **lsmrule) > + void **lsmrule, gfp_t gfp) > LSM_HOOK(int, 0, audit_rule_known, struct audit_krule *krule) > LSM_HOOK(int, 0, audit_rule_match, u32 secid, u32 field, u32 op, void *lsmrule) > LSM_HOOK(void, LSM_RET_VOID, audit_rule_free, void *lsmrule) > diff --git a/include/linux/security.h b/include/linux/security.h > index 21cf70346b33..de3af33e6ff5 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -2048,7 +2048,8 @@ static inline void security_key_post_create_or_update(struct key *keyring, > > #ifdef CONFIG_AUDIT > #ifdef CONFIG_SECURITY > -int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule); > +int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule, > + gfp_t gfp); > int security_audit_rule_known(struct audit_krule *krule); > int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule); > void security_audit_rule_free(void *lsmrule); > @@ -2056,7 +2057,7 @@ void security_audit_rule_free(void *lsmrule); > #else > > static inline int security_audit_rule_init(u32 field, u32 op, char *rulestr, > - void **lsmrule) > + void **lsmrule, gfp_t gfp) > { > return 0; > } > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c > index be8c680121e4..d6ef4f4f9cba 100644 > --- a/kernel/auditfilter.c > +++ b/kernel/auditfilter.c > @@ -529,7 +529,8 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, > entry->rule.buflen += f_val; > f->lsm_str = str; > err = security_audit_rule_init(f->type, f->op, str, > - (void **)&f->lsm_rule); > + (void **)&f->lsm_rule, > + GFP_KERNEL); > /* Keep currently invalid fields around in case they > * become valid after a policy reload. */ > if (err == -EINVAL) { > @@ -799,7 +800,7 @@ static inline int audit_dupe_lsm_field(struct audit_field *df, > > /* our own (refreshed) copy of lsm_rule */ > ret = security_audit_rule_init(df->type, df->op, df->lsm_str, > - (void **)&df->lsm_rule); > + (void **)&df->lsm_rule, GFP_KERNEL); > /* Keep currently invalid fields around in case they > * become valid after a policy reload. */ > if (ret == -EINVAL) { > diff --git a/security/apparmor/audit.c b/security/apparmor/audit.c > index 45beb1c5f747..6b5181c668b5 100644 > --- a/security/apparmor/audit.c > +++ b/security/apparmor/audit.c > @@ -217,7 +217,7 @@ void aa_audit_rule_free(void *vrule) > } > } > > -int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) > +int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule, gfp_t gfp) > { > struct aa_audit_rule *rule; > > @@ -230,14 +230,14 @@ int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) > return -EINVAL; > } > > - rule = kzalloc(sizeof(struct aa_audit_rule), GFP_KERNEL); > + rule = kzalloc(sizeof(struct aa_audit_rule), gfp); > > if (!rule) > return -ENOMEM; > > /* Currently rules are treated as coming from the root ns */ > rule->label = aa_label_parse(&root_ns->unconfined->label, rulestr, > - GFP_KERNEL, true, false); > + gfp, true, false); > if (IS_ERR(rule->label)) { > int err = PTR_ERR(rule->label); > aa_audit_rule_free(rule); > diff --git a/security/apparmor/include/audit.h b/security/apparmor/include/audit.h > index acbb03b9bd25..0c8cc86b417b 100644 > --- a/security/apparmor/include/audit.h > +++ b/security/apparmor/include/audit.h > @@ -200,7 +200,7 @@ static inline int complain_error(int error) > } > > void aa_audit_rule_free(void *vrule); > -int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule); > +int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule, gfp_t gfp); > int aa_audit_rule_known(struct audit_krule *rule); > int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule); > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index 3e568126cd48..c51e24d24d1e 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -546,7 +546,7 @@ static inline void ima_free_modsig(struct modsig *modsig) > #else > > static inline int ima_filter_rule_init(u32 field, u32 op, char *rulestr, > - void **lsmrule) > + void **lsmrule, gfp_t gfp) > { > return -EINVAL; > } > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c > index c0556907c2e6..09da8e639239 100644 > --- a/security/integrity/ima/ima_policy.c > +++ b/security/integrity/ima/ima_policy.c > @@ -401,7 +401,8 @@ static void ima_free_rule(struct ima_rule_entry *entry) > kfree(entry); > } > > -static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry) > +static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry, > + gfp_t gfp) > { > struct ima_rule_entry *nentry; > int i; > @@ -410,7 +411,7 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry) > * Immutable elements are copied over as pointers and data; only > * lsm rules can change > */ > - nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL); > + nentry = kmemdup(entry, sizeof(*nentry), gfp); > if (!nentry) > return NULL; > > @@ -425,7 +426,8 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry) > > ima_filter_rule_init(nentry->lsm[i].type, Audit_equal, > nentry->lsm[i].args_p, > - &nentry->lsm[i].rule); > + &nentry->lsm[i].rule, > + gfp); > if (!nentry->lsm[i].rule) > pr_warn("rule for LSM \'%s\' is undefined\n", > nentry->lsm[i].args_p); > @@ -438,7 +440,7 @@ static int ima_lsm_update_rule(struct ima_rule_entry *entry) > int i; > struct ima_rule_entry *nentry; > > - nentry = ima_lsm_copy_rule(entry); > + nentry = ima_lsm_copy_rule(entry, GFP_KERNEL); > if (!nentry) > return -ENOMEM; > > @@ -664,7 +666,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, > } > > if (rc == -ESTALE && !rule_reinitialized) { > - lsm_rule = ima_lsm_copy_rule(rule); > + lsm_rule = ima_lsm_copy_rule(rule, GFP_ATOMIC); > if (lsm_rule) { > rule_reinitialized = true; > goto retry; > @@ -1140,7 +1142,8 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry, > entry->lsm[lsm_rule].type = audit_type; > result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal, > entry->lsm[lsm_rule].args_p, > - &entry->lsm[lsm_rule].rule); > + &entry->lsm[lsm_rule].rule, > + GFP_KERNEL); > if (!entry->lsm[lsm_rule].rule) { > pr_warn("rule for LSM \'%s\' is undefined\n", > entry->lsm[lsm_rule].args_p); > diff --git a/security/security.c b/security/security.c > index e5da848c50b9..e5ca08789f74 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -5332,15 +5332,17 @@ void security_key_post_create_or_update(struct key *keyring, struct key *key, > * @op: rule operator > * @rulestr: rule context > * @lsmrule: receive buffer for audit rule struct > + * @gfp: GFP flag used for kmalloc > * > * Allocate and initialize an LSM audit rule structure. > * > * Return: Return 0 if @lsmrule has been successfully set, -EINVAL in case of > * an invalid rule. > */ > -int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule) > +int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule, > + gfp_t gfp) > { > - return call_int_hook(audit_rule_init, field, op, rulestr, lsmrule); > + return call_int_hook(audit_rule_init, field, op, rulestr, lsmrule, gfp); > } > > /** > diff --git a/security/selinux/include/audit.h b/security/selinux/include/audit.h > index 52aca71210b4..29c7d4c86f6d 100644 > --- a/security/selinux/include/audit.h > +++ b/security/selinux/include/audit.h > @@ -21,12 +21,14 @@ > * @op: the operator the rule uses > * @rulestr: the text "target" of the rule > * @rule: pointer to the new rule structure returned via this > + * @gfp: GFP flag used for kmalloc > * > * Returns 0 if successful, -errno if not. On success, the rule structure > * will be allocated internally. The caller must free this structure with > * selinux_audit_rule_free() after use. > */ > -int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **rule); > +int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **rule, > + gfp_t gfp); > > /** > * selinux_audit_rule_free - free an selinux audit rule structure. > diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c > index f20e1968b7f7..e33e55384b75 100644 > --- a/security/selinux/ss/services.c > +++ b/security/selinux/ss/services.c > @@ -3507,7 +3507,8 @@ void selinux_audit_rule_free(void *vrule) > } > } > > -int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) > +int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule, > + gfp_t gfp) > { > struct selinux_state *state = &selinux_state; > struct selinux_policy *policy; > @@ -3548,7 +3549,7 @@ int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) > return -EINVAL; > } > > - tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL); > + tmprule = kzalloc(sizeof(struct selinux_audit_rule), gfp); > if (!tmprule) > return -ENOMEM; > context_init(&tmprule->au_ctxt); > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 70ba2841e181..f5cbec1e6a92 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -4693,11 +4693,13 @@ static int smack_post_notification(const struct cred *w_cred, > * @op: required testing operator (=, !=, >, <, ...) > * @rulestr: smack label to be audited > * @vrule: pointer to save our own audit rule representation > + * @gfp: type of the memory for the allocation > * > * Prepare to audit cases where (@field @op @rulestr) is true. > * The label to be audited is created if necessay. > */ > -static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) > +static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule, > + gfp_t gfp) > { > struct smack_known *skp; > char **rule = (char **)vrule; >
