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author | Eric W. Biederman <ebiederm@xmission.com> | 2013-04-09 02:22:10 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-19 11:38:47 -0700 |
commit | 60106c06452e7db66d13ce8286d89b9cce13664d (patch) | |
tree | ad60ff737f7636f9f45fff84f8826369d09f5923 | |
parent | 3e717373db383369e5887708c3cde25f396f648e (diff) | |
download | lwn-60106c06452e7db66d13ce8286d89b9cce13664d.tar.gz lwn-60106c06452e7db66d13ce8286d89b9cce13664d.zip |
audit: Make testing for a valid loginuid explicit.
commit 780a7654cee8d61819512385e778e4827db4bfbc upstream.
audit rule additions containing "-F auid!=4294967295" were failing
with EINVAL because of a regression caused by e1760bd.
Apparently some userland audit rule sets want to know if loginuid uid
has been set and are using a test for auid != 4294967295 to determine
that.
In practice that is a horrible way to ask if a value has been set,
because it relies on subtle implementation details and will break
every time the uid implementation in the kernel changes.
So add a clean way to test if the audit loginuid has been set, and
silently convert the old idiom to the cleaner and more comprehensible
new idiom.
RGB notes: In upstream, audit_rule_to_entry has been refactored out.
This is patch is already upstream in functionally the same form in
commit 780a7654cee8d61819512385e778e4827db4bfbc . The decimal constant
was cast to unsigned to quiet GCC 4.6 32-bit architecture warnings.
Reported-By: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Backported-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | include/linux/audit.h | 5 | ||||
-rw-r--r-- | include/uapi/linux/audit.h | 1 | ||||
-rw-r--r-- | kernel/auditfilter.c | 31 | ||||
-rw-r--r-- | kernel/auditsc.c | 5 |
4 files changed, 40 insertions, 2 deletions
diff --git a/include/linux/audit.h b/include/linux/audit.h index 37464c592c92..b4086cf9b7e5 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -390,6 +390,11 @@ static inline void audit_ptrace(struct task_struct *t) #define audit_signals 0 #endif /* CONFIG_AUDITSYSCALL */ +static inline bool audit_loginuid_set(struct task_struct *tsk) +{ + return uid_valid(audit_get_loginuid(tsk)); +} + #ifdef CONFIG_AUDIT /* These are defined in audit.c */ /* Public API */ diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 9f096f1c0907..9554a19d3414 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -246,6 +246,7 @@ #define AUDIT_OBJ_TYPE 21 #define AUDIT_OBJ_LEV_LOW 22 #define AUDIT_OBJ_LEV_HIGH 23 +#define AUDIT_LOGINUID_SET 24 /* These are ONLY useful when checking * at syscall exit time (AUDIT_AT_EXIT). */ diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index f9fc54bbe06f..2bf508dfec15 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -345,6 +345,12 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) f->uid = INVALID_UID; f->gid = INVALID_GID; + /* Support legacy tests for a valid loginuid */ + if ((f->type == AUDIT_LOGINUID) && (f->val == 4294967295U)) { + f->type = AUDIT_LOGINUID_SET; + f->val = 0; + } + err = -EINVAL; if (f->op == Audit_bad) goto exit_free; @@ -352,6 +358,12 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) switch(f->type) { default: goto exit_free; + case AUDIT_LOGINUID_SET: + if ((f->val != 0) && (f->val != 1)) + goto exit_free; + if (f->op != Audit_not_equal && f->op != Audit_equal) + goto exit_free; + break; case AUDIT_UID: case AUDIT_EUID: case AUDIT_SUID: @@ -459,7 +471,20 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, f->gid = INVALID_GID; f->lsm_str = NULL; f->lsm_rule = NULL; - switch(f->type) { + + /* Support legacy tests for a valid loginuid */ + if ((f->type == AUDIT_LOGINUID) && (f->val == 4294967295U)) { + f->type = AUDIT_LOGINUID_SET; + f->val = 0; + } + + switch (f->type) { + case AUDIT_LOGINUID_SET: + if ((f->val != 0) && (f->val != 1)) + goto exit_free; + if (f->op != Audit_not_equal && f->op != Audit_equal) + goto exit_free; + break; case AUDIT_UID: case AUDIT_EUID: case AUDIT_SUID: @@ -1378,6 +1403,10 @@ static int audit_filter_user_rules(struct audit_krule *rule, result = audit_uid_comparator(audit_get_loginuid(current), f->op, f->uid); break; + case AUDIT_LOGINUID_SET: + result = audit_comparator(audit_loginuid_set(current), + f->op, f->val); + break; case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: diff --git a/kernel/auditsc.c b/kernel/auditsc.c index a371f857a0a9..c4b72b0e07cb 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -742,6 +742,9 @@ static int audit_filter_rules(struct task_struct *tsk, if (ctx) result = audit_uid_comparator(tsk->loginuid, f->op, f->uid); break; + case AUDIT_LOGINUID_SET: + result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val); + break; case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: @@ -2309,7 +2312,7 @@ int audit_set_loginuid(kuid_t loginuid) unsigned int sessionid; #ifdef CONFIG_AUDIT_LOGINUID_IMMUTABLE - if (uid_valid(task->loginuid)) + if (audit_loginuid_set(task)) return -EPERM; #else /* CONFIG_AUDIT_LOGINUID_IMMUTABLE */ if (!capable(CAP_AUDIT_CONTROL)) |