From: Casey Schaufler <casey@schaufler-ca.com> To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: casey@schaufler-ca.com, linux-audit@redhat.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org Subject: [PATCH v33 26/29] Audit: Add record for multiple task security contexts Date: Thu, 10 Mar 2022 15:46:29 -0800 [thread overview] Message-ID: <20220310234632.16194-27-casey@schaufler-ca.com> (raw) In-Reply-To: <20220310234632.16194-1-casey@schaufler-ca.com> Create a new audit record AUDIT_MAC_TASK_CONTEXTS. An example of the MAC_TASK_CONTEXTS (1420) record is: type=MAC_TASK_CONTEXTS[1420] msg=audit(1600880931.832:113) subj_apparmor=unconfined subj_smack=_ When an audit event includes a AUDIT_MAC_TASK_CONTEXTS record the "subj=" field in other records in the event will be "subj=?". An AUDIT_MAC_TASK_CONTEXTS record is supplied when the system has multiple security modules that may make access decisions based on a subject security context. Functions are created to manage the skb list in the audit_buffer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- include/uapi/linux/audit.h | 1 + kernel/audit.c | 104 ++++++++++++++++++++++++++++++++----- 2 files changed, 93 insertions(+), 12 deletions(-) diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 8eda133ca4c1..af0aaccfaf57 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -143,6 +143,7 @@ #define AUDIT_MAC_UNLBL_STCDEL 1417 /* NetLabel: del a static label */ #define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */ #define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */ +#define AUDIT_MAC_TASK_CONTEXTS 1420 /* Multiple LSM task contexts */ #define AUDIT_FIRST_KERN_ANOM_MSG 1700 #define AUDIT_LAST_KERN_ANOM_MSG 1799 diff --git a/kernel/audit.c b/kernel/audit.c index 4713e66a12af..ad825af203cf 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -2147,8 +2147,65 @@ void audit_log_key(struct audit_buffer *ab, char *key) audit_log_format(ab, "(null)"); } +/* + * A brief note on aux record management. + * + * Aux records are allocated and added to the skb list of + * the "main" record. The ab->skb is reset to point to the + * aux record on its creation. When the aux record in complete + * ab->skb has to be reset to point to the "main" record. + * This allows the audit_log_ functions to be ignorant of + * which kind of record it is logging to. It also avoids adding + * special data for aux records. + */ + +/** + * audit_buffer_aux_new - Add an aux record buffer to the skb list + * @ab: audit_buffer + * @type: message type + * + * On success ab->skb will point to the new aux record. + * Returns 0 on success, -ENOMEM should allocation fail. + */ +static int audit_buffer_aux_new(struct audit_buffer *ab, int type) +{ + WARN_ON(ab->skb != skb_peek(&ab->skb_list)); + + ab->skb = nlmsg_new(AUDIT_BUFSIZ, ab->gfp_mask); + if (!ab->skb) + goto err; + if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) + goto err; + skb_queue_tail(&ab->skb_list, ab->skb); + + audit_log_format(ab, "audit(%llu.%03lu:%u): ", + (unsigned long long)ab->stamp.ctime.tv_sec, + ab->stamp.ctime.tv_nsec/1000000, + ab->stamp.serial); + + return 0; + +err: + kfree_skb(ab->skb); + ab->skb = skb_peek(&ab->skb_list); + return -ENOMEM; +} + +/** + * audit_buffer_aux_end - Switch back to the "main" record from an aux record + * @ab: audit_buffer + * + * Restores the "main" audit record to ab->skb. + */ +static void audit_buffer_aux_end(struct audit_buffer *ab) +{ + ab->skb = skb_peek(&ab->skb_list); +} + + int audit_log_task_context(struct audit_buffer *ab) { + int i; int error; struct lsmblob blob; struct lsmcontext context; @@ -2157,16 +2214,44 @@ int audit_log_task_context(struct audit_buffer *ab) if (!lsmblob_is_set(&blob)) return 0; - error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST); + if (!lsm_multiple_contexts()) { + error = security_secid_to_secctx(&blob, &context, + LSMBLOB_FIRST); + if (error) { + if (error != -EINVAL) + goto error_path; + return 0; + } - if (error) { - if (error != -EINVAL) + audit_log_format(ab, " subj=%s", context.context); + security_release_secctx(&context); + } else { + /* Multiple LSMs provide contexts. Include an aux record. */ + audit_log_format(ab, " subj=?"); + error = audit_buffer_aux_new(ab, AUDIT_MAC_TASK_CONTEXTS); + if (error) goto error_path; - return 0; + for (i = 0; i < LSMBLOB_ENTRIES; i++) { + if (blob.secid[i] == 0) + continue; + error = security_secid_to_secctx(&blob, &context, i); + if (error) { + if (error != -EINVAL) + audit_panic("error in audit_log_task_context"); + audit_log_format(ab, "%ssubj_%s=?", + i ? " " : "", + lsm_slot_to_name(i)); + } else { + audit_log_format(ab, "%ssubj_%s=%s", + i ? " " : "", + lsm_slot_to_name(i), + context.context); + security_release_secctx(&context); + } + } + audit_buffer_aux_end(ab); } - audit_log_format(ab, " subj=%s", context.context); - security_release_secctx(&context); return 0; error_path: @@ -2382,13 +2467,8 @@ int audit_signal_info(int sig, struct task_struct *t) } /** - * __audit_log_end - end one audit record + * __audit_log_end - send one audit record * @skb: the buffer to send - * - * We can not do a netlink send inside an irq context because it blocks (last - * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a - * queue and a kthread is scheduled to remove them from the queue outside the - * irq context. May be called in any context. */ static void __audit_log_end(struct sk_buff *skb) { -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: Casey Schaufler <casey@schaufler-ca.com> To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: john.johansen@canonical.com, linux-kernel@vger.kernel.org, linux-audit@redhat.com Subject: [PATCH v33 26/29] Audit: Add record for multiple task security contexts Date: Thu, 10 Mar 2022 15:46:29 -0800 [thread overview] Message-ID: <20220310234632.16194-27-casey@schaufler-ca.com> (raw) In-Reply-To: <20220310234632.16194-1-casey@schaufler-ca.com> Create a new audit record AUDIT_MAC_TASK_CONTEXTS. An example of the MAC_TASK_CONTEXTS (1420) record is: type=MAC_TASK_CONTEXTS[1420] msg=audit(1600880931.832:113) subj_apparmor=unconfined subj_smack=_ When an audit event includes a AUDIT_MAC_TASK_CONTEXTS record the "subj=" field in other records in the event will be "subj=?". An AUDIT_MAC_TASK_CONTEXTS record is supplied when the system has multiple security modules that may make access decisions based on a subject security context. Functions are created to manage the skb list in the audit_buffer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- include/uapi/linux/audit.h | 1 + kernel/audit.c | 104 ++++++++++++++++++++++++++++++++----- 2 files changed, 93 insertions(+), 12 deletions(-) diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 8eda133ca4c1..af0aaccfaf57 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -143,6 +143,7 @@ #define AUDIT_MAC_UNLBL_STCDEL 1417 /* NetLabel: del a static label */ #define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */ #define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */ +#define AUDIT_MAC_TASK_CONTEXTS 1420 /* Multiple LSM task contexts */ #define AUDIT_FIRST_KERN_ANOM_MSG 1700 #define AUDIT_LAST_KERN_ANOM_MSG 1799 diff --git a/kernel/audit.c b/kernel/audit.c index 4713e66a12af..ad825af203cf 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -2147,8 +2147,65 @@ void audit_log_key(struct audit_buffer *ab, char *key) audit_log_format(ab, "(null)"); } +/* + * A brief note on aux record management. + * + * Aux records are allocated and added to the skb list of + * the "main" record. The ab->skb is reset to point to the + * aux record on its creation. When the aux record in complete + * ab->skb has to be reset to point to the "main" record. + * This allows the audit_log_ functions to be ignorant of + * which kind of record it is logging to. It also avoids adding + * special data for aux records. + */ + +/** + * audit_buffer_aux_new - Add an aux record buffer to the skb list + * @ab: audit_buffer + * @type: message type + * + * On success ab->skb will point to the new aux record. + * Returns 0 on success, -ENOMEM should allocation fail. + */ +static int audit_buffer_aux_new(struct audit_buffer *ab, int type) +{ + WARN_ON(ab->skb != skb_peek(&ab->skb_list)); + + ab->skb = nlmsg_new(AUDIT_BUFSIZ, ab->gfp_mask); + if (!ab->skb) + goto err; + if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) + goto err; + skb_queue_tail(&ab->skb_list, ab->skb); + + audit_log_format(ab, "audit(%llu.%03lu:%u): ", + (unsigned long long)ab->stamp.ctime.tv_sec, + ab->stamp.ctime.tv_nsec/1000000, + ab->stamp.serial); + + return 0; + +err: + kfree_skb(ab->skb); + ab->skb = skb_peek(&ab->skb_list); + return -ENOMEM; +} + +/** + * audit_buffer_aux_end - Switch back to the "main" record from an aux record + * @ab: audit_buffer + * + * Restores the "main" audit record to ab->skb. + */ +static void audit_buffer_aux_end(struct audit_buffer *ab) +{ + ab->skb = skb_peek(&ab->skb_list); +} + + int audit_log_task_context(struct audit_buffer *ab) { + int i; int error; struct lsmblob blob; struct lsmcontext context; @@ -2157,16 +2214,44 @@ int audit_log_task_context(struct audit_buffer *ab) if (!lsmblob_is_set(&blob)) return 0; - error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST); + if (!lsm_multiple_contexts()) { + error = security_secid_to_secctx(&blob, &context, + LSMBLOB_FIRST); + if (error) { + if (error != -EINVAL) + goto error_path; + return 0; + } - if (error) { - if (error != -EINVAL) + audit_log_format(ab, " subj=%s", context.context); + security_release_secctx(&context); + } else { + /* Multiple LSMs provide contexts. Include an aux record. */ + audit_log_format(ab, " subj=?"); + error = audit_buffer_aux_new(ab, AUDIT_MAC_TASK_CONTEXTS); + if (error) goto error_path; - return 0; + for (i = 0; i < LSMBLOB_ENTRIES; i++) { + if (blob.secid[i] == 0) + continue; + error = security_secid_to_secctx(&blob, &context, i); + if (error) { + if (error != -EINVAL) + audit_panic("error in audit_log_task_context"); + audit_log_format(ab, "%ssubj_%s=?", + i ? " " : "", + lsm_slot_to_name(i)); + } else { + audit_log_format(ab, "%ssubj_%s=%s", + i ? " " : "", + lsm_slot_to_name(i), + context.context); + security_release_secctx(&context); + } + } + audit_buffer_aux_end(ab); } - audit_log_format(ab, " subj=%s", context.context); - security_release_secctx(&context); return 0; error_path: @@ -2382,13 +2467,8 @@ int audit_signal_info(int sig, struct task_struct *t) } /** - * __audit_log_end - end one audit record + * __audit_log_end - send one audit record * @skb: the buffer to send - * - * We can not do a netlink send inside an irq context because it blocks (last - * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a - * queue and a kthread is scheduled to remove them from the queue outside the - * irq context. May be called in any context. */ static void __audit_log_end(struct sk_buff *skb) { -- 2.31.1 -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
next prev parent reply other threads:[~2022-03-10 23:59 UTC|newest] Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <20220310234632.16194-1-casey.ref@schaufler-ca.com> 2022-03-10 23:46 ` [PATCH v33 00/29] LSM: Module stacking for AppArmor Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 01/29] integrity: disassociate ima_filter_rule from security_audit_rule Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-11 10:48 ` kernel test robot 2022-03-11 10:48 ` kernel test robot 2022-03-10 23:46 ` [PATCH v33 02/29] LSM: Infrastructure management of the sock security Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 03/29] LSM: Add the lsmblob data structure Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 04/29] LSM: provide lsm name and id slot mappings Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 05/29] IMA: avoid label collisions with stacked LSMs Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 06/29] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 07/29] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 08/29] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 09/29] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 10/29] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 11/29] LSM: Use lsmblob in security_current_getsecid Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 12/29] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 13/29] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-11 7:52 ` kernel test robot 2022-03-11 7:52 ` kernel test robot 2022-03-11 9:16 ` kernel test robot 2022-03-11 9:16 ` kernel test robot 2022-03-12 4:50 ` kernel test robot 2022-03-12 4:50 ` kernel test robot 2022-03-10 23:46 ` [PATCH v33 14/29] LSM: Specify which LSM to display Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 15/29] LSM: Ensure the correct LSM context releaser Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 16/29] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 17/29] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 18/29] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 19/29] NET: Store LSM netlabel data in a lsmblob Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 20/29] binder: Pass LSM identifier for confirmation Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 21/29] LSM: Extend security_secid_to_secctx to include module selection Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 22/29] Audit: Keep multiple LSM data in audit_names Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 23/29] Audit: Create audit_stamp structure Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 24/29] LSM: Add a function to report multiple LSMs Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 25/29] Audit: Allow multiple records in an audit_buffer Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-15 23:47 ` Paul Moore 2022-03-15 23:47 ` Paul Moore 2022-03-16 0:06 ` Casey Schaufler 2022-03-16 0:06 ` Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler [this message] 2022-03-10 23:46 ` [PATCH v33 26/29] Audit: Add record for multiple task security contexts Casey Schaufler 2022-03-15 23:47 ` Paul Moore 2022-03-15 23:47 ` Paul Moore 2022-03-16 0:17 ` Casey Schaufler 2022-03-16 0:17 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 27/29] Audit: Add record for multiple object " Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-15 23:47 ` Paul Moore 2022-03-15 23:47 ` Paul Moore 2022-03-16 0:23 ` Casey Schaufler 2022-03-16 0:23 ` Casey Schaufler 2022-03-16 1:08 ` Paul Moore 2022-03-16 1:08 ` Paul Moore 2022-03-10 23:46 ` [PATCH v33 28/29] LSM: Add /proc attr entry for full LSM context Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler 2022-03-10 23:46 ` [PATCH v33 29/29] AppArmor: Remove the exclusive flag Casey Schaufler 2022-03-10 23:46 ` Casey Schaufler
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