From 60106c06452e7db66d13ce8286d89b9cce13664d Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 9 Apr 2013 02:22:10 -0700 Subject: 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 Signed-off-by: "Eric W. Biederman" Tested-by: Richard Guy Briggs Signed-off-by: Eric Paris Backported-by: Richard Guy Briggs Signed-off-by: Greg Kroah-Hartman --- include/linux/audit.h | 5 +++++ include/uapi/linux/audit.h | 1 + kernel/auditfilter.c | 31 ++++++++++++++++++++++++++++++- 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)) -- cgit v1.2.3