lkml.org 
[lkml]   [2013]   [Oct]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/3] audit: call audit_bprm() only once to add AUDIT_EXECVE information
Date
Move the audit_bprm() call from search_binary_handler() to exec_binprm().  This
allows us to get rid of the mm member of struct audit_aux_data_execve since
bprm->mm will equal current->mm.

This also mitigates the issue that ->argc could be modified by the
load_binary() call in search_binary_handler().

audit_bprm() was being called to add an AUDIT_EXECVE record to the audit
context every time search_binary_handler() was recursively called. Only one
reference is necessary. Merge the remaining argc parameter into the union in
audit_context, removing a kmalloc.

Reported-by: Oleg Nesterov <onestero@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
fs/exec.c | 5 +----
include/linux/audit.h | 13 +++++--------
kernel/audit.h | 3 +++
kernel/auditsc.c | 41 ++++++++++-------------------------------
4 files changed, 19 insertions(+), 43 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 8875dd1..47d7edb 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1385,10 +1385,6 @@ int search_binary_handler(struct linux_binprm *bprm)
if (retval)
return retval;

- retval = audit_bprm(bprm);
- if (retval)
- return retval;
-
retval = -ENOENT;
retry:
read_lock(&binfmt_lock);
@@ -1436,6 +1432,7 @@ static int exec_binprm(struct linux_binprm *bprm)

ret = search_binary_handler(bprm);
if (ret >= 0) {
+ audit_bprm(bprm);
trace_sched_process_exec(current, old_pid, bprm);
ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
current->did_exec = 1;
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 729a4d1..a757e6c 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -207,7 +207,7 @@ static inline int audit_get_sessionid(struct task_struct *tsk)

extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp);
extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode);
-extern int __audit_bprm(struct linux_binprm *bprm);
+extern void __audit_bprm(struct linux_binprm *bprm);
extern int __audit_socketcall(int nargs, unsigned long *args);
extern int __audit_sockaddr(int len, void *addr);
extern void __audit_fd_pair(int fd1, int fd2);
@@ -236,11 +236,10 @@ static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid
if (unlikely(!audit_dummy_context()))
__audit_ipc_set_perm(qbytes, uid, gid, mode);
}
-static inline int audit_bprm(struct linux_binprm *bprm)
+static inline void audit_bprm(struct linux_binprm *bprm)
{
if (unlikely(!audit_dummy_context()))
- return __audit_bprm(bprm);
- return 0;
+ __audit_bprm(bprm);
}
static inline int audit_socketcall(int nargs, unsigned long *args)
{
@@ -367,10 +366,8 @@ static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid,
gid_t gid, umode_t mode)
{ }
-static inline int audit_bprm(struct linux_binprm *bprm)
-{
- return 0;
-}
+static inline void audit_bprm(struct linux_binprm *bprm)
+{ }
static inline int audit_socketcall(int nargs, unsigned long *args)
{
return 0;
diff --git a/kernel/audit.h b/kernel/audit.h
index 123c9b7..b779642 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -197,6 +197,9 @@ struct audit_context {
int fd;
int flags;
} mmap;
+ struct {
+ int argc;
+ } execve;
};
int fds[2];

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index c9abaa0..dc1adee 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -95,12 +95,6 @@ struct audit_aux_data {
/* Number of target pids per aux struct. */
#define AUDIT_AUX_PIDS 16

-struct audit_aux_data_execve {
- struct audit_aux_data d;
- int argc;
- struct mm_struct *mm;
-};
-
struct audit_aux_data_pids {
struct audit_aux_data d;
pid_t target_pid[AUDIT_AUX_PIDS];
@@ -1144,20 +1138,16 @@ static int audit_log_single_execve_arg(struct audit_context *context,
}

static void audit_log_execve_info(struct audit_context *context,
- struct audit_buffer **ab,
- struct audit_aux_data_execve *axi)
+ struct audit_buffer **ab)
{
int i, len;
size_t len_sent = 0;
const char __user *p;
char *buf;

- if (axi->mm != current->mm)
- return; /* execve failed, no additional info */
-
- p = (const char __user *)axi->mm->arg_start;
+ p = (const char __user *)current->mm->arg_start;

- audit_log_format(*ab, "argc=%d", axi->argc);
+ audit_log_format(*ab, "argc=%d", context->execve.argc);

/*
* we need some kernel buffer to hold the userspace args. Just
@@ -1171,7 +1161,7 @@ static void audit_log_execve_info(struct audit_context *context,
return;
}

- for (i = 0; i < axi->argc; i++) {
+ for (i = 0; i < context->execve.argc; i++) {
len = audit_log_single_execve_arg(context, ab, i,
&len_sent, p, buf);
if (len <= 0)
@@ -1274,6 +1264,9 @@ static void show_special(struct audit_context *context, int *call_panic)
audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
context->mmap.flags);
break; }
+ case AUDIT_EXECVE: {
+ audit_log_execve_info(context, &ab);
+ break; }
}
audit_log_end(ab);
}
@@ -1320,11 +1313,6 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts

switch (aux->type) {

- case AUDIT_EXECVE: {
- struct audit_aux_data_execve *axi = (void *)aux;
- audit_log_execve_info(context, &ab, axi);
- break; }
-
case AUDIT_BPRM_FCAPS: {
struct audit_aux_data_bprm_fcaps *axs = (void *)aux;
audit_log_format(ab, "fver=%x", axs->fcap_ver);
@@ -2121,21 +2109,12 @@ void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mo
context->ipc.has_perm = 1;
}

-int __audit_bprm(struct linux_binprm *bprm)
+void __audit_bprm(struct linux_binprm *bprm)
{
- struct audit_aux_data_execve *ax;
struct audit_context *context = current->audit_context;

- ax = kmalloc(sizeof(*ax), GFP_KERNEL);
- if (!ax)
- return -ENOMEM;
-
- ax->argc = bprm->argc;
- ax->mm = bprm->mm;
- ax->d.type = AUDIT_EXECVE;
- ax->d.next = context->aux;
- context->aux = (void *)ax;
- return 0;
+ context->type = AUDIT_EXECVE;
+ context->execve.argc = bprm->argc;
}


--
1.7.1


\
 
 \ /
  Last update: 2013-10-31 01:41    [W:0.026 / U:4.000 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site