From 55dfc5da1a9b7e623b6f35620c74280555df0288 Mon Sep 17 00:00:00 2001 From: José Bollo Date: Wed, 8 Jan 2014 15:53:05 +0100 Subject: Minor improvement of 'smack_sb_kern_mount' MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix a possible memory access fault when transmute is true and isp is NULL. Signed-off-by: José Bollo --- security/smack/smack_lsm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index d814e35987be..efa42991235e 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -413,9 +413,11 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data) * Initialize the root inode. */ isp = inode->i_security; - if (inode->i_security == NULL) { - inode->i_security = new_inode_smack(sp->smk_root); - isp = inode->i_security; + if (isp == NULL) { + isp = new_inode_smack(sp->smk_root); + if (isp == NULL) + return -ENOMEM; + inode->i_security = isp; } else isp->smk_inode = sp->smk_root; -- cgit v1.2.3 From 959e6c7f1eee42f14d31755b1134f5615db1d9bc Mon Sep 17 00:00:00 2001 From: Lukasz Pawelczyk Date: Tue, 11 Mar 2014 17:07:04 +0100 Subject: Smack: fix the subject/object order in smack_ptrace_traceme() The order of subject/object is currently reversed in smack_ptrace_traceme(). It is currently checked if the tracee has a capability to trace tracer and according to this rule a decision is made whether the tracer will be allowed to trace tracee. Signed-off-by: Lukasz Pawelczyk Signed-off-by: Rafal Krypa --- security/smack/smack.h | 1 + security/smack/smack_access.c | 33 ++++++++++++++++++++++++++------- security/smack/smack_lsm.c | 4 ++-- 3 files changed, 29 insertions(+), 9 deletions(-) (limited to 'security') diff --git a/security/smack/smack.h b/security/smack/smack.h index d072fd32212d..b9dfc4e1d3e0 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -225,6 +225,7 @@ struct inode_smack *new_inode_smack(char *); */ int smk_access_entry(char *, char *, struct list_head *); int smk_access(struct smack_known *, char *, int, struct smk_audit_info *); +int smk_tskacc(struct task_smack *, char *, u32, struct smk_audit_info *); int smk_curacc(char *, u32, struct smk_audit_info *); struct smack_known *smack_from_secid(const u32); char *smk_parse_smack(const char *string, int len); diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index 14293cd9b1e5..f161debed02b 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -192,20 +192,21 @@ out_audit: } /** - * smk_curacc - determine if current has a specific access to an object + * smk_tskacc - determine if a task has a specific access to an object + * @tsp: a pointer to the subject task * @obj_label: a pointer to the object's Smack label * @mode: the access requested, in "MAY" format * @a : common audit data * - * This function checks the current subject label/object label pair + * This function checks the subject task's label/object label pair * in the access rule list and returns 0 if the access is permitted, - * non zero otherwise. It allows that current may have the capability + * non zero otherwise. It allows that the task may have the capability * to override the rules. */ -int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) +int smk_tskacc(struct task_smack *subject, char *obj_label, + u32 mode, struct smk_audit_info *a) { - struct task_smack *tsp = current_security(); - struct smack_known *skp = smk_of_task(tsp); + struct smack_known *skp = smk_of_task(subject); int may; int rc; @@ -219,7 +220,7 @@ int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) * it can further restrict access. */ may = smk_access_entry(skp->smk_known, obj_label, - &tsp->smk_rules); + &subject->smk_rules); if (may < 0) goto out_audit; if ((mode & may) == mode) @@ -241,6 +242,24 @@ out_audit: return rc; } +/** + * smk_curacc - determine if current has a specific access to an object + * @obj_label: a pointer to the object's Smack label + * @mode: the access requested, in "MAY" format + * @a : common audit data + * + * This function checks the current subject label/object label pair + * in the access rule list and returns 0 if the access is permitted, + * non zero otherwise. It allows that current may have the capability + * to override the rules. + */ +int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) +{ + struct task_smack *tsp = current_security(); + + return smk_tskacc(tsp, obj_label, mode, a); +} + #ifdef CONFIG_AUDIT /** * smack_str_from_perm : helper to transalate an int to a diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index efa42991235e..b23fbdd4cdad 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -207,11 +207,11 @@ static int smack_ptrace_traceme(struct task_struct *ptp) if (rc != 0) return rc; - skp = smk_of_task(task_security(ptp)); + skp = smk_of_task(current_security()); smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); smk_ad_setfield_u_tsk(&ad, ptp); - rc = smk_curacc(skp->smk_known, MAY_READWRITE, &ad); + rc = smk_tskacc(ptp, skp->smk_known, MAY_READWRITE, &ad); return rc; } -- cgit v1.2.3 From 5663884caab166f87ab8c68ec7c62b1cce85a400 Mon Sep 17 00:00:00 2001 From: Lukasz Pawelczyk Date: Tue, 11 Mar 2014 17:07:05 +0100 Subject: Smack: unify all ptrace accesses in the smack The decision whether we can trace a process is made in the following functions: smack_ptrace_traceme() smack_ptrace_access_check() smack_bprm_set_creds() (in case the proces is traced) This patch unifies all those decisions by introducing one function that checks whether ptrace is allowed: smk_ptrace_rule_check(). This makes possible to actually trace with TRACEME where first the TRACEME itself must be allowed and then exec() on a traced process. Additional bugs fixed: - The decision is made according to the mode parameter that is now correctly translated from PTRACE_MODE_* to MAY_* instead of being treated 1:1. PTRACE_MODE_READ requires MAY_READ. PTRACE_MODE_ATTACH requires MAY_READWRITE. - Add a smack audit log in case of exec() refused by bprm_set_creds(). - Honor the PTRACE_MODE_NOAUDIT flag and don't put smack audit info in case this flag is set. Signed-off-by: Lukasz Pawelczyk Signed-off-by: Rafal Krypa --- security/smack/smack_lsm.c | 84 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 71 insertions(+), 13 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index b23fbdd4cdad..4d6f37644baa 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -157,6 +157,54 @@ static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead, return rc; } +/** + * smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_* + * @mode - input mode in form of PTRACE_MODE_* + * + * Returns a converted MAY_* mode usable by smack rules + */ +static inline unsigned int smk_ptrace_mode(unsigned int mode) +{ + switch (mode) { + case PTRACE_MODE_READ: + return MAY_READ; + case PTRACE_MODE_ATTACH: + return MAY_READWRITE; + } + + return 0; +} + +/** + * smk_ptrace_rule_check - helper for ptrace access + * @tracer: tracer process + * @tracee_label: label of the process that's about to be traced + * @mode: ptrace attachment mode (PTRACE_MODE_*) + * @func: name of the function that called us, used for audit + * + * Returns 0 on access granted, -error on error + */ +static int smk_ptrace_rule_check(struct task_struct *tracer, char *tracee_label, + unsigned int mode, const char *func) +{ + int rc; + struct smk_audit_info ad, *saip = NULL; + struct task_smack *tsp; + struct smack_known *skp; + + if ((mode & PTRACE_MODE_NOAUDIT) == 0) { + smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK); + smk_ad_setfield_u_tsk(&ad, tracer); + saip = &ad; + } + + tsp = task_security(tracer); + skp = smk_of_task(tsp); + + rc = smk_tskacc(tsp, tracee_label, smk_ptrace_mode(mode), saip); + return rc; +} + /* * LSM hooks. * We he, that is fun! @@ -165,16 +213,15 @@ static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead, /** * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH * @ctp: child task pointer - * @mode: ptrace attachment mode + * @mode: ptrace attachment mode (PTRACE_MODE_*) * * Returns 0 if access is OK, an error code otherwise * - * Do the capability checks, and require read and write. + * Do the capability checks. */ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) { int rc; - struct smk_audit_info ad; struct smack_known *skp; rc = cap_ptrace_access_check(ctp, mode); @@ -182,10 +229,8 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) return rc; skp = smk_of_task(task_security(ctp)); - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); - smk_ad_setfield_u_tsk(&ad, ctp); - rc = smk_curacc(skp->smk_known, mode, &ad); + rc = smk_ptrace_rule_check(current, skp->smk_known, mode, __func__); return rc; } @@ -195,12 +240,11 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) * * Returns 0 if access is OK, an error code otherwise * - * Do the capability checks, and require read and write. + * Do the capability checks, and require PTRACE_MODE_ATTACH. */ static int smack_ptrace_traceme(struct task_struct *ptp) { int rc; - struct smk_audit_info ad; struct smack_known *skp; rc = cap_ptrace_traceme(ptp); @@ -208,10 +252,9 @@ static int smack_ptrace_traceme(struct task_struct *ptp) return rc; skp = smk_of_task(current_security()); - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); - smk_ad_setfield_u_tsk(&ad, ptp); - rc = smk_tskacc(ptp, skp->smk_known, MAY_READWRITE, &ad); + rc = smk_ptrace_rule_check(ptp, skp->smk_known, + PTRACE_MODE_ATTACH, __func__); return rc; } @@ -455,7 +498,7 @@ static int smack_sb_statfs(struct dentry *dentry) * smack_bprm_set_creds - set creds for exec * @bprm: the exec information * - * Returns 0 if it gets a blob, -ENOMEM otherwise + * Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise */ static int smack_bprm_set_creds(struct linux_binprm *bprm) { @@ -475,7 +518,22 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task) return 0; - if (bprm->unsafe) + if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { + struct task_struct *tracer; + rc = 0; + + rcu_read_lock(); + tracer = ptrace_parent(current); + if (likely(tracer != NULL)) + rc = smk_ptrace_rule_check(tracer, + isp->smk_task->smk_known, + PTRACE_MODE_ATTACH, + __func__); + rcu_read_unlock(); + + if (rc != 0) + return rc; + } else if (bprm->unsafe) return -EPERM; bsp->smk_task = isp->smk_task; -- cgit v1.2.3 From 668678185247303450e60df14569f94cf5775fea Mon Sep 17 00:00:00 2001 From: Lukasz Pawelczyk Date: Tue, 11 Mar 2014 17:07:06 +0100 Subject: Smack: adds smackfs/ptrace interface This allows to limit ptrace beyond the regular smack access rules. It adds a smackfs/ptrace interface that allows smack to be configured to require equal smack labels for PTRACE_MODE_ATTACH access. See the changes in Documentation/security/Smack.txt below for details. Signed-off-by: Lukasz Pawelczyk Signed-off-by: Rafal Krypa --- Documentation/security/Smack.txt | 10 ++++++ security/smack/smack.h | 9 +++++ security/smack/smack_access.c | 5 ++- security/smack/smack_lsm.c | 22 +++++++++++- security/smack/smackfs.c | 74 ++++++++++++++++++++++++++++++++++++++++ 5 files changed, 118 insertions(+), 2 deletions(-) (limited to 'security') diff --git a/Documentation/security/Smack.txt b/Documentation/security/Smack.txt index 7a2d30c132e3..5597917703e0 100644 --- a/Documentation/security/Smack.txt +++ b/Documentation/security/Smack.txt @@ -204,6 +204,16 @@ onlycap these capabilities are effective at for processes with any label. The value is set by writing the desired label to the file or cleared by writing "-" to the file. +ptrace + This is used to define the current ptrace policy + 0 - default: this is the policy that relies on smack access rules. + For the PTRACE_READ a subject needs to have a read access on + object. For the PTRACE_ATTACH a read-write access is required. + 1 - exact: this is the policy that limits PTRACE_ATTACH. Attach is + only allowed when subject's and object's labels are equal. + PTRACE_READ is not affected. Can be overriden with CAP_SYS_PTRACE. + 2 - draconian: this policy behaves like the 'exact' above with an + exception that it can't be overriden with CAP_SYS_PTRACE. revoke-subject Writing a Smack label here sets the access to '-' for all access rules with that subject label. diff --git a/security/smack/smack.h b/security/smack/smack.h index b9dfc4e1d3e0..fade085b1128 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -176,6 +176,14 @@ struct smk_port_label { */ #define SMACK_CIPSO_MAXCATNUM 184 /* 23 * 8 */ +/* + * Ptrace rules + */ +#define SMACK_PTRACE_DEFAULT 0 +#define SMACK_PTRACE_EXACT 1 +#define SMACK_PTRACE_DRACONIAN 2 +#define SMACK_PTRACE_MAX SMACK_PTRACE_DRACONIAN + /* * Flags for untraditional access modes. * It shouldn't be necessary to avoid conflicts with definitions @@ -245,6 +253,7 @@ extern struct smack_known *smack_net_ambient; extern struct smack_known *smack_onlycap; extern struct smack_known *smack_syslog_label; extern const char *smack_cipso_option; +extern int smack_ptrace_rule; extern struct smack_known smack_known_floor; extern struct smack_known smack_known_hat; diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index f161debed02b..c062e9467b62 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -304,7 +304,10 @@ static void smack_log_callback(struct audit_buffer *ab, void *a) audit_log_untrustedstring(ab, sad->subject); audit_log_format(ab, " object="); audit_log_untrustedstring(ab, sad->object); - audit_log_format(ab, " requested=%s", sad->request); + if (sad->request[0] == '\0') + audit_log_format(ab, " labels_differ"); + else + audit_log_format(ab, " requested=%s", sad->request); } /** diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 4d6f37644baa..787dcf12f15c 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -178,7 +178,8 @@ static inline unsigned int smk_ptrace_mode(unsigned int mode) /** * smk_ptrace_rule_check - helper for ptrace access * @tracer: tracer process - * @tracee_label: label of the process that's about to be traced + * @tracee_label: label of the process that's about to be traced, + * the pointer must originate from smack structures * @mode: ptrace attachment mode (PTRACE_MODE_*) * @func: name of the function that called us, used for audit * @@ -201,6 +202,25 @@ static int smk_ptrace_rule_check(struct task_struct *tracer, char *tracee_label, tsp = task_security(tracer); skp = smk_of_task(tsp); + if ((mode & PTRACE_MODE_ATTACH) && + (smack_ptrace_rule == SMACK_PTRACE_EXACT || + smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) { + if (skp->smk_known == tracee_label) + rc = 0; + else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN) + rc = -EACCES; + else if (capable(CAP_SYS_PTRACE)) + rc = 0; + else + rc = -EACCES; + + if (saip) + smack_log(skp->smk_known, tracee_label, 0, rc, saip); + + return rc; + } + + /* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */ rc = smk_tskacc(tsp, tracee_label, smk_ptrace_mode(mode), saip); return rc; } diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 3198cfe1dcc6..177d87875394 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -53,6 +53,7 @@ enum smk_inos { SMK_REVOKE_SUBJ = 18, /* set rules with subject label to '-' */ SMK_CHANGE_RULE = 19, /* change or add rules (long labels) */ SMK_SYSLOG = 20, /* change syslog label) */ + SMK_PTRACE = 21, /* set ptrace rule */ }; /* @@ -100,6 +101,15 @@ struct smack_known *smack_onlycap; */ struct smack_known *smack_syslog_label; +/* + * Ptrace current rule + * SMACK_PTRACE_DEFAULT regular smack ptrace rules (/proc based) + * SMACK_PTRACE_EXACT labels must match, but can be overriden with + * CAP_SYS_PTRACE + * SMACK_PTRACE_DRACONIAN lables must match, CAP_SYS_PTRACE has no effect + */ +int smack_ptrace_rule = SMACK_PTRACE_DEFAULT; + /* * Certain IP addresses may be designated as single label hosts. * Packets are sent there unlabeled, but only from tasks that @@ -2243,6 +2253,68 @@ static const struct file_operations smk_syslog_ops = { }; +/** + * smk_read_ptrace - read() for /smack/ptrace + * @filp: file pointer, not actually used + * @buf: where to put the result + * @count: maximum to send along + * @ppos: where to start + * + * Returns number of bytes read or error code, as appropriate + */ +static ssize_t smk_read_ptrace(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + char temp[32]; + ssize_t rc; + + if (*ppos != 0) + return 0; + + sprintf(temp, "%d\n", smack_ptrace_rule); + rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp)); + return rc; +} + +/** + * smk_write_ptrace - write() for /smack/ptrace + * @file: file pointer + * @buf: data from user space + * @count: bytes sent + * @ppos: where to start - must be 0 + */ +static ssize_t smk_write_ptrace(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + char temp[32]; + int i; + + if (!smack_privileged(CAP_MAC_ADMIN)) + return -EPERM; + + if (*ppos != 0 || count >= sizeof(temp) || count == 0) + return -EINVAL; + + if (copy_from_user(temp, buf, count) != 0) + return -EFAULT; + + temp[count] = '\0'; + + if (sscanf(temp, "%d", &i) != 1) + return -EINVAL; + if (i < SMACK_PTRACE_DEFAULT || i > SMACK_PTRACE_MAX) + return -EINVAL; + smack_ptrace_rule = i; + + return count; +} + +static const struct file_operations smk_ptrace_ops = { + .write = smk_write_ptrace, + .read = smk_read_ptrace, + .llseek = default_llseek, +}; + /** * smk_fill_super - fill the smackfs superblock * @sb: the empty superblock @@ -2296,6 +2368,8 @@ static int smk_fill_super(struct super_block *sb, void *data, int silent) "change-rule", &smk_change_rule_ops, S_IRUGO|S_IWUSR}, [SMK_SYSLOG] = { "syslog", &smk_syslog_ops, S_IRUGO|S_IWUSR}, + [SMK_PTRACE] = { + "ptrace", &smk_ptrace_ops, S_IRUGO|S_IWUSR}, /* last one */ {""} }; -- cgit v1.2.3 From 5e9ab593c2da3064136ffa1d7f712d0e957e1958 Mon Sep 17 00:00:00 2001 From: Pankaj Kumar Date: Fri, 13 Dec 2013 15:12:22 +0530 Subject: bugfix patch for SMACK 1. In order to remove any SMACK extended attribute from a file, a user should have CAP_MAC_ADMIN capability. But user without having this capability is able to remove SMACK64MMAP security attribute. 2. While validating size and value of smack extended attribute in smack_inode_setsecurity hook, wrong error code is returned. Signed-off-by: Pankaj Kumar Signed-off-by: Himanshu Shukla --- 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 787dcf12f15c..9a99f3c485cb 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1018,7 +1018,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 || - strcmp(name, XATTR_NAME_SMACKMMAP)) { + strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { if (!smack_privileged(CAP_MAC_ADMIN)) rc = -EPERM; } else @@ -2156,7 +2156,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name, int rc = 0; if (value == NULL || size > SMK_LONGLABEL || size == 0) - return -EACCES; + return -EINVAL; skp = smk_import_entry(value, size); if (skp == NULL) -- cgit v1.2.3 From 9598f4c9e7069aee8639be1e04e8af26b5a77fa2 Mon Sep 17 00:00:00 2001 From: José Bollo Date: Thu, 3 Apr 2014 13:48:41 +0200 Subject: SMACK: Fix handling value==NULL in post setxattr MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The function `smack_inode_post_setxattr` is called each time that a setxattr is done, for any value of name. The kernel allow to put value==NULL when size==0 to set an empty attribute value. The systematic call to smk_import_entry was causing the dereference of a NULL pointer hence a KERNEL PANIC! The problem can be produced easily by issuing the command `setfattr -n user.data file` under bash prompt when SMACK is active. Moving the call to smk_import_entry as proposed by this patch is correcting the behaviour because the function smack_inode_post_setxattr is called for the SMACK's attributes only if the function smack_inode_setxattr validated the value and its size (what will not be the case when size==0). It also has a benefical effect to not fill the smack hash with garbage values coming from any extended attribute write. Change-Id: Iaf0039c2be9bccb6cee11c24a3b44d209101fe47 Signed-off-by: José Bollo --- security/smack/smack_lsm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 9a99f3c485cb..a5d86ffbf9a0 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -960,18 +960,20 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, return; } - skp = smk_import_entry(value, size); if (strcmp(name, XATTR_NAME_SMACK) == 0) { + skp = smk_import_entry(value, size); if (skp != NULL) isp->smk_inode = skp->smk_known; else isp->smk_inode = smack_known_invalid.smk_known; } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) { + skp = smk_import_entry(value, size); if (skp != NULL) 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 (skp != NULL) isp->smk_mmap = skp; else -- cgit v1.2.3 From f59bdfba3e2b0ba5182f23d96101d106f18132ca Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Thu, 10 Apr 2014 16:35:36 -0700 Subject: Smack: Correctly remove SMACK64TRANSMUTE attribute Sam Henderson points out that removing the SMACK64TRANSMUTE attribute from a directory does not result in the directory transmuting. This is because the inode flag indicating that the directory is transmuting isn't cleared. The fix is a tad less than trivial because smk_task and smk_mmap should have been broken out, too. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index a5d86ffbf9a0..3d1c9086d0d6 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1026,18 +1026,31 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) } else rc = cap_inode_removexattr(dentry, name); + if (rc != 0) + return rc; + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); smk_ad_setfield_u_fs_path_dentry(&ad, dentry); - if (rc == 0) - rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); - if (rc == 0) { - isp = dentry->d_inode->i_security; + rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); + if (rc != 0) + return rc; + + isp = dentry->d_inode->i_security; + /* + * Don't do anything special for these. + * XATTR_NAME_SMACKIPIN + * XATTR_NAME_SMACKIPOUT + * XATTR_NAME_SMACKEXEC + */ + if (strcmp(name, XATTR_NAME_SMACK) == 0) isp->smk_task = NULL; + else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) isp->smk_mmap = NULL; - } + else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) + isp->smk_flags &= ~SMK_INODE_TRANSMUTE; - return rc; + return 0; } /** -- cgit v1.2.3 From 54e70ec5eb090193b03e69d551fa6771a5a217c4 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Thu, 10 Apr 2014 16:37:08 -0700 Subject: Smack: bidirectional UDS connect check Smack IPC policy requires that the sender have write access to the receiver. UDS streams don't do per-packet checks. The only check is done at connect time. The existing code checks if the connecting process can write to the other, but not the other way around. This change adds a check that the other end can write to the connecting process. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schuafler --- security/smack/smack.h | 6 +++--- security/smack/smack_lsm.c | 44 ++++++++++++++++++++++++-------------------- 2 files changed, 27 insertions(+), 23 deletions(-) (limited to 'security') diff --git a/security/smack/smack.h b/security/smack/smack.h index fade085b1128..020307ef0972 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -80,8 +80,8 @@ struct superblock_smack { struct socket_smack { struct smack_known *smk_out; /* outbound label */ - char *smk_in; /* inbound label */ - char *smk_packet; /* TCP peer label */ + struct smack_known *smk_in; /* inbound label */ + struct smack_known *smk_packet; /* TCP peer label */ }; /* @@ -133,7 +133,7 @@ struct smk_port_label { struct list_head list; struct sock *smk_sock; /* socket initialized on */ unsigned short smk_port; /* the port number */ - char *smk_in; /* incoming label */ + struct smack_known *smk_in; /* inbound label */ struct smack_known *smk_out; /* outgoing label */ }; diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 3d1c9086d0d6..3410e3abd19b 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1095,7 +1095,7 @@ static int smack_inode_getsecurity(const struct inode *inode, ssp = sock->sk->sk_security; if (strcmp(name, XATTR_SMACK_IPIN) == 0) - isp = ssp->smk_in; + isp = ssp->smk_in->smk_known; else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) isp = ssp->smk_out->smk_known; else @@ -1859,7 +1859,7 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) if (ssp == NULL) return -ENOMEM; - ssp->smk_in = skp->smk_known; + ssp->smk_in = skp; ssp->smk_out = skp; ssp->smk_packet = NULL; @@ -2099,7 +2099,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address, if (act == SMK_RECEIVING) { skp = smack_net_ambient; - object = ssp->smk_in; + object = ssp->smk_in->smk_known; } else { skp = ssp->smk_out; object = smack_net_ambient->smk_known; @@ -2129,9 +2129,9 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address, list_for_each_entry(spp, &smk_ipv6_port_list, list) { if (spp->smk_port != port) continue; - object = spp->smk_in; + object = spp->smk_in->smk_known; if (act == SMK_CONNECTING) - ssp->smk_packet = spp->smk_out->smk_known; + ssp->smk_packet = spp->smk_out; break; } @@ -2195,7 +2195,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name, ssp = sock->sk->sk_security; if (strcmp(name, XATTR_SMACK_IPIN) == 0) - ssp->smk_in = skp->smk_known; + ssp->smk_in = skp; else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) { ssp->smk_out = skp; if (sock->sk->sk_family == PF_INET) { @@ -3054,30 +3054,34 @@ static int smack_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk) { struct smack_known *skp; + struct smack_known *okp; struct socket_smack *ssp = sock->sk_security; struct socket_smack *osp = other->sk_security; struct socket_smack *nsp = newsk->sk_security; struct smk_audit_info ad; int rc = 0; - #ifdef CONFIG_AUDIT struct lsm_network_audit net; - - smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); - smk_ad_setfield_u_net_sk(&ad, other); #endif if (!smack_privileged(CAP_MAC_OVERRIDE)) { skp = ssp->smk_out; - rc = smk_access(skp, osp->smk_in, MAY_WRITE, &ad); + okp = osp->smk_out; +#ifdef CONFIG_AUDIT + smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); + smk_ad_setfield_u_net_sk(&ad, other); +#endif + rc = smk_access(skp, okp->smk_known, MAY_WRITE, &ad); + if (rc == 0) + rc = smk_access(okp, okp->smk_known, MAY_WRITE, NULL); } /* * Cross reference the peer labels for SO_PEERSEC. */ if (rc == 0) { - nsp->smk_packet = ssp->smk_out->smk_known; - ssp->smk_packet = osp->smk_out->smk_known; + nsp->smk_packet = ssp->smk_out; + ssp->smk_packet = osp->smk_out; } return rc; @@ -3109,7 +3113,7 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other) return 0; skp = ssp->smk_out; - return smk_access(skp, osp->smk_in, MAY_WRITE, &ad); + return smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad); } /** @@ -3204,7 +3208,7 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap, if (found) return skp; - if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known) + if (ssp != NULL && ssp->smk_in == &smack_known_star) return &smack_known_web; return &smack_known_star; } @@ -3323,7 +3327,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) * This is the simplist possible security model * for networking. */ - rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad); + rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad); if (rc != 0) netlbl_skbuff_err(skb, rc, 0); break; @@ -3358,7 +3362,7 @@ static int smack_socket_getpeersec_stream(struct socket *sock, ssp = sock->sk->sk_security; if (ssp->smk_packet != NULL) { - rcp = ssp->smk_packet; + rcp = ssp->smk_packet->smk_known; slen = strlen(rcp) + 1; } @@ -3443,7 +3447,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent) return; ssp = sk->sk_security; - ssp->smk_in = skp->smk_known; + ssp->smk_in = skp; ssp->smk_out = skp; /* cssp->smk_packet is already set in smack_inet_csk_clone() */ } @@ -3503,7 +3507,7 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb, * Receiving a packet requires that the other end be able to write * here. Read access is not required. */ - rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad); + rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad); if (rc != 0) return rc; @@ -3547,7 +3551,7 @@ static void smack_inet_csk_clone(struct sock *sk, if (req->peer_secid != 0) { skp = smack_from_secid(req->peer_secid); - ssp->smk_packet = skp->smk_known; + ssp->smk_packet = skp; } else ssp->smk_packet = NULL; } -- cgit v1.2.3 From a6834c0b9114c06106efee8e9f2a11fbbb104567 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Mon, 21 Apr 2014 11:10:26 -0700 Subject: Smack: Verify read access on file open - v3 Smack believes that many of the operatons that can be performed on an open file descriptor are read operations. The fstat and lseek system calls are examples. An implication of this is that files shouldn't be open if the task doesn't have read access even if it has write access and the file is being opened write only. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 3410e3abd19b..7bcf9edf768d 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1462,19 +1462,32 @@ static int smack_file_receive(struct file *file) /** * smack_file_open - Smack dentry open processing * @file: the object - * @cred: unused + * @cred: task credential * * Set the security blob in the file structure. + * Allow the open only if the task has read access. There are + * many read operations (e.g. fstat) that you can do with an + * fd even if you have the file open write-only. * * Returns 0 */ static int smack_file_open(struct file *file, const struct cred *cred) { + struct task_smack *tsp = cred->security; struct inode_smack *isp = file_inode(file)->i_security; + struct smk_audit_info ad; + int rc; - file->f_security = isp->smk_inode; + if (smack_privileged(CAP_MAC_OVERRIDE)) + return 0; - return 0; + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); + smk_ad_setfield_u_fs_path(&ad, file->f_path); + rc = smk_access(tsp->smk_task, isp->smk_inode, MAY_READ, &ad); + if (rc == 0) + file->f_security = isp->smk_inode; + + return rc; } /* -- cgit v1.2.3 From 36ea735b522d09826ae0dac0e540f294436c52f3 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Mon, 28 Apr 2014 15:23:01 -0700 Subject: Smack: Label cgroup files for systemd The cgroup filesystem isn't ready for an LSM to properly use extented attributes. This patch makes files created in the cgroup filesystem usable by a system running Smack and systemd. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 7bcf9edf768d..9cb7559d60b2 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2821,6 +2821,15 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) * of the superblock. */ if (opt_dentry->d_parent == opt_dentry) { + if (sbp->s_magic == CGROUP_SUPER_MAGIC) { + /* + * The cgroup filesystem is never mounted, + * so there's no opportunity to set the mount + * options. + */ + sbsp->smk_root = smack_known_star.smk_known; + sbsp->smk_default = smack_known_star.smk_known; + } isp->smk_inode = sbsp->smk_root; isp->smk_flags |= SMK_INODE_INSTANT; goto unlockandout; @@ -2834,16 +2843,20 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) */ switch (sbp->s_magic) { case SMACK_MAGIC: + case PIPEFS_MAGIC: + case SOCKFS_MAGIC: + case CGROUP_SUPER_MAGIC: /* * Casey says that it's a little embarrassing * that the smack file system doesn't do * extended attributes. - */ - final = smack_known_star.smk_known; - break; - case PIPEFS_MAGIC: - /* + * * Casey says pipes are easy (?) + * + * Socket access is controlled by the socket + * structures associated with the task involved. + * + * Cgroupfs is special */ final = smack_known_star.smk_known; break; @@ -2855,13 +2868,6 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) */ final = ckp->smk_known; break; - case SOCKFS_MAGIC: - /* - * Socket access is controlled by the socket - * structures associated with the task involved. - */ - final = smack_known_star.smk_known; - break; case PROC_SUPER_MAGIC: /* * Casey says procfs appears not to care. -- cgit v1.2.3 From ec554fa75ec94dcf47e52db9551755679c10235b Mon Sep 17 00:00:00 2001 From: Toralf Förster Date: Sun, 27 Apr 2014 19:33:34 +0200 Subject: Warning in scanf string typing MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This fixes a warning about the mismatch of types between the declared unsigned and integer. Signed-off-by: Toralf Förster --- security/smack/smackfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security') diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 177d87875394..32b248820840 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -1193,7 +1193,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, data[count] = '\0'; - rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd/%d %s", + rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd/%u %s", &host[0], &host[1], &host[2], &host[3], &m, smack); if (rc != 6) { rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd %s", -- cgit v1.2.3