From 08382c9f6efe08b8bb30645c2744480cbd8f161a Mon Sep 17 00:00:00 2001 From: jooseong lee Date: Thu, 3 Nov 2016 11:54:39 +0100 Subject: Smack: Assign smack_known_web label for kernel thread's Assign smack_known_web label for kernel thread's socket Creating struct sock by sk_alloc function in various kernel subsystems like bluetooth doesn't call smack_socket_post_create(). In such case, received sock label is the floor('_') label and makes access deny. Signed-off-by: jooseong lee Acked-by: Casey Schaufler --- security/smack/smack_lsm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 1cb060293505..e73460d5acc6 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2337,8 +2337,16 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) if (ssp == NULL) return -ENOMEM; - ssp->smk_in = skp; - ssp->smk_out = skp; + /* + * Sockets created by kernel threads receive web label. + */ + if (unlikely(current->flags & PF_KTHREAD)) { + ssp->smk_in = &smack_known_web; + ssp->smk_out = &smack_known_web; + } else { + ssp->smk_in = skp; + ssp->smk_out = skp; + } ssp->smk_packet = NULL; sk->sk_security = ssp; -- cgit v1.2.1 From 2097f59920ea81516d7783396683cad22c26d140 Mon Sep 17 00:00:00 2001 From: Himanshu Shukla Date: Thu, 10 Nov 2016 16:19:52 +0530 Subject: smack: parse mnt opts after privileges check In smack_set_mnt_opts()first the SMACK mount options are being parsed and later it is being checked whether the user calling mount has CAP_MAC_ADMIN capability. This sequence of operationis will allow unauthorized user to add SMACK labels in label list and may cause denial of security attack by adding many labels by allocating kernel memory by unauthorized user. Superblock smack flag is also being set as initialized though function may return with EPERM error. First check the capability of calling user then set the SMACK attributes and smk_flags. Signed-off-by: Himanshu Shukla Acked-by: Casey Schaufler --- security/smack/smack_lsm.c | 50 +++++++++++++++++++++++----------------------- 1 file changed, 25 insertions(+), 25 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index e73460d5acc6..788a5faf3774 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -769,6 +769,31 @@ static int smack_set_mnt_opts(struct super_block *sb, if (sp->smk_flags & SMK_SB_INITIALIZED) return 0; + if (!smack_privileged(CAP_MAC_ADMIN)) { + /* + * Unprivileged mounts don't get to specify Smack values. + */ + if (num_opts) + return -EPERM; + /* + * Unprivileged mounts get root and default from the caller. + */ + skp = smk_of_current(); + sp->smk_root = skp; + sp->smk_default = skp; + /* + * For a handful of fs types with no user-controlled + * backing store it's okay to trust security labels + * in the filesystem. The rest are untrusted. + */ + if (sb->s_user_ns != &init_user_ns && + sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC && + sb->s_magic != RAMFS_MAGIC) { + transmute = 1; + sp->smk_flags |= SMK_SB_UNTRUSTED; + } + } + sp->smk_flags |= SMK_SB_INITIALIZED; for (i = 0; i < num_opts; i++) { @@ -809,31 +834,6 @@ static int smack_set_mnt_opts(struct super_block *sb, } } - if (!smack_privileged(CAP_MAC_ADMIN)) { - /* - * Unprivileged mounts don't get to specify Smack values. - */ - if (num_opts) - return -EPERM; - /* - * Unprivileged mounts get root and default from the caller. - */ - skp = smk_of_current(); - sp->smk_root = skp; - sp->smk_default = skp; - /* - * For a handful of fs types with no user-controlled - * backing store it's okay to trust security labels - * in the filesystem. The rest are untrusted. - */ - if (sb->s_user_ns != &init_user_ns && - sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC && - sb->s_magic != RAMFS_MAGIC) { - transmute = 1; - sp->smk_flags |= SMK_SB_UNTRUSTED; - } - } - /* * Initialize the root inode. */ -- cgit v1.2.1 From 7128ea159d60a91b3f0a7d10a1ea7d62b53cda93 Mon Sep 17 00:00:00 2001 From: Himanshu Shukla Date: Thu, 10 Nov 2016 16:17:49 +0530 Subject: SMACK: Do not apply star label in smack_setprocattr hook Smack prohibits processes from using the star ("*") and web ("@") labels. Checks have been added in other functions. In smack_setprocattr() hook, only check for web ("@") label has been added and restricted from applying web ("@") label. Check for star ("*") label should also be added in smack_setprocattr() hook. Return error should be "-EINVAL" not "-EPERM" as permission is there for setting label but not the label value as star ("*") or web ("@"). Signed-off-by: Himanshu Shukla Acked-by: Casey Schaufler --- security/smack/smack_lsm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 788a5faf3774..3a5684b47354 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3669,10 +3669,11 @@ static int smack_setprocattr(struct task_struct *p, char *name, return PTR_ERR(skp); /* - * No process is ever allowed the web ("@") label. + * No process is ever allowed the web ("@") label + * and the star ("*") label. */ - if (skp == &smack_known_web) - return -EPERM; + if (skp == &smack_known_web || skp == &smack_known_star) + return -EINVAL; if (!smack_privileged(CAP_MAC_ADMIN)) { rc = -EPERM; -- cgit v1.2.1 From b437aba85b5c4689543409d8407c016749231aae Mon Sep 17 00:00:00 2001 From: Himanshu Shukla Date: Thu, 10 Nov 2016 16:17:02 +0530 Subject: SMACK: Fix the memory leak in smack_cred_prepare() hook Memory leak in smack_cred_prepare()function. smack_cred_prepare() hook returns error if there is error in allocating memory in smk_copy_rules() or smk_copy_relabel() function. If smack_cred_prepare() function returns error then the calling function should call smack_cred_free() function for cleanup. In smack_cred_free() function first credential is extracted and then all rules are deleted. In smack_cred_prepare() function security field is assigned in the end when all function return success. But this function may return before and memory will not be freed. Signed-off-by: Himanshu Shukla Acked-by: Casey Schaufler --- security/smack/smack_lsm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 3a5684b47354..f7ee77c3db55 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2023,6 +2023,8 @@ static int smack_cred_prepare(struct cred *new, const struct cred *old, if (new_tsp == NULL) return -ENOMEM; + new->security = new_tsp; + rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp); if (rc != 0) return rc; @@ -2032,7 +2034,6 @@ static int smack_cred_prepare(struct cred *new, const struct cred *old, if (rc != 0) return rc; - new->security = new_tsp; return 0; } -- cgit v1.2.1 From 2e4939f7026f938a1dc81533d020801198562804 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Mon, 7 Nov 2016 19:01:09 -0800 Subject: Smack: ipv6 label match fix The check for a deleted entry in the list of IPv6 host addresses was being performed in the wrong place, leading to most peculiar results in some cases. This puts the check into the right place. Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index f7ee77c3db55..b2c839f735c0 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2443,18 +2443,18 @@ static struct smack_known *smack_ipv6host_label(struct sockaddr_in6 *sip) return NULL; list_for_each_entry_rcu(snp, &smk_net6addr_list, list) { + /* + * If the label is NULL the entry has + * been renounced. Ignore it. + */ + if (snp->smk_label == NULL) + continue; /* * we break after finding the first match because * the list is sorted from longest to shortest mask * so we have found the most specific match */ for (found = 1, i = 0; i < 8; i++) { - /* - * If the label is NULL the entry has - * been renounced. Ignore it. - */ - if (snp->smk_label == NULL) - continue; if ((sap->s6_addr16[i] & snp->smk_mask.s6_addr16[i]) != snp->smk_host.s6_addr16[i]) { found = 0; -- cgit v1.2.1 From 8c15d66e429afd099b66f05393527c23f85ca41c Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Mon, 14 Nov 2016 20:12:55 +0900 Subject: Smack: Use GFP_KERNEL for smack_parse_opts_str(). Since smack_parse_opts_str() is calling match_strdup() which uses GFP_KERNEL, it is safe to use GFP_KERNEL from kcalloc() which is called by smack_parse_opts_str(). Signed-off-by: Tetsuo Handa Acked-by: Casey Schaufler --- security/smack/smack_lsm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index b2c839f735c0..46d8be434466 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -692,12 +692,12 @@ static int smack_parse_opts_str(char *options, } } - opts->mnt_opts = kcalloc(NUM_SMK_MNT_OPTS, sizeof(char *), GFP_ATOMIC); + opts->mnt_opts = kcalloc(NUM_SMK_MNT_OPTS, sizeof(char *), GFP_KERNEL); if (!opts->mnt_opts) goto out_err; opts->mnt_opts_flags = kcalloc(NUM_SMK_MNT_OPTS, sizeof(int), - GFP_ATOMIC); + GFP_KERNEL); if (!opts->mnt_opts_flags) { kfree(opts->mnt_opts); goto out_err; -- cgit v1.2.1 From 152f91d4d11a30106b9cc0b27b47e0e80b633ee8 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Mon, 14 Nov 2016 09:38:15 -0800 Subject: Smack: Remove unnecessary smack_known_invalid The invalid Smack label ("") and the Huh ("?") Smack label serve the same purpose and having both is unnecessary. While pulling out the invalid label it became clear that the use of smack_from_secid() was inconsistent, so that is repaired. The setting of inode labels to the invalid label could never happen in a functional system, has never been observed in the wild and is not what you'd really want for a failure behavior in any case. That is removed. Signed-off-by: Casey Schaufler --- security/smack/smack.h | 1 - security/smack/smack_access.c | 7 +------ security/smack/smack_lsm.c | 29 +++-------------------------- security/smack/smackfs.c | 3 --- 4 files changed, 4 insertions(+), 36 deletions(-) (limited to 'security') diff --git a/security/smack/smack.h b/security/smack/smack.h index 51fd30192c08..77abe2efacae 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -336,7 +336,6 @@ extern int smack_ptrace_rule; extern struct smack_known smack_known_floor; extern struct smack_known smack_known_hat; extern struct smack_known smack_known_huh; -extern struct smack_known smack_known_invalid; extern struct smack_known smack_known_star; extern struct smack_known smack_known_web; diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index 23e5808a0970..356e3764cad9 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -36,11 +36,6 @@ struct smack_known smack_known_floor = { .smk_secid = 5, }; -struct smack_known smack_known_invalid = { - .smk_known = "", - .smk_secid = 6, -}; - struct smack_known smack_known_web = { .smk_known = "@", .smk_secid = 7, @@ -615,7 +610,7 @@ struct smack_known *smack_from_secid(const u32 secid) * of a secid that is not on the list. */ rcu_read_unlock(); - return &smack_known_invalid; + return &smack_known_huh; } /* diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 46d8be434466..4d90257d03ad 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1384,20 +1384,14 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, skp = smk_import_entry(value, size); if (!IS_ERR(skp)) isp->smk_inode = skp; - else - isp->smk_inode = &smack_known_invalid; } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) { skp = smk_import_entry(value, size); if (!IS_ERR(skp)) isp->smk_task = skp; - else - isp->smk_task = &smack_known_invalid; } else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { skp = smk_import_entry(value, size); if (!IS_ERR(skp)) isp->smk_mmap = skp; - else - isp->smk_mmap = &smack_known_invalid; } return; @@ -2068,12 +2062,8 @@ static void smack_cred_transfer(struct cred *new, const struct cred *old) static int smack_kernel_act_as(struct cred *new, u32 secid) { struct task_smack *new_tsp = new->security; - struct smack_known *skp = smack_from_secid(secid); - - if (skp == NULL) - return -EINVAL; - new_tsp->smk_task = skp; + new_tsp->smk_task = smack_from_secid(secid); return 0; } @@ -3894,21 +3884,11 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap, return &smack_known_web; return &smack_known_star; } - if ((sap->flags & NETLBL_SECATTR_SECID) != 0) { + if ((sap->flags & NETLBL_SECATTR_SECID) != 0) /* * Looks like a fallback, which gives us a secid. */ - skp = smack_from_secid(sap->attr.secid); - /* - * This has got to be a bug because it is - * impossible to specify a fallback without - * specifying the label, which will ensure - * it has a secid, and the only way to get a - * secid is from a fallback. - */ - BUG_ON(skp == NULL); - return skp; - } + return smack_from_secid(sap->attr.secid); /* * Without guidance regarding the smack value * for the packet fall back on the network @@ -4771,7 +4751,6 @@ static __init void init_smack_known_list(void) mutex_init(&smack_known_hat.smk_rules_lock); mutex_init(&smack_known_floor.smk_rules_lock); mutex_init(&smack_known_star.smk_rules_lock); - mutex_init(&smack_known_invalid.smk_rules_lock); mutex_init(&smack_known_web.smk_rules_lock); /* * Initialize rule lists @@ -4780,7 +4759,6 @@ static __init void init_smack_known_list(void) INIT_LIST_HEAD(&smack_known_hat.smk_rules); INIT_LIST_HEAD(&smack_known_star.smk_rules); INIT_LIST_HEAD(&smack_known_floor.smk_rules); - INIT_LIST_HEAD(&smack_known_invalid.smk_rules); INIT_LIST_HEAD(&smack_known_web.smk_rules); /* * Create the known labels list @@ -4789,7 +4767,6 @@ static __init void init_smack_known_list(void) smk_insert_entry(&smack_known_hat); smk_insert_entry(&smack_known_star); smk_insert_entry(&smack_known_floor); - smk_insert_entry(&smack_known_invalid); smk_insert_entry(&smack_known_web); } diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 6492fe96cae4..13743a01b35b 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -2996,9 +2996,6 @@ static int __init init_smk_fs(void) if (err == 0 && rc < 0) err = rc; rc = smk_preset_netlabel(&smack_known_huh); - if (err == 0 && rc < 0) - err = rc; - rc = smk_preset_netlabel(&smack_known_invalid); if (err == 0 && rc < 0) err = rc; rc = smk_preset_netlabel(&smack_known_star); -- cgit v1.2.1