Re: [PATCH] audit: get comm using lock to avoid race in string printing

From: Stephen Smalley
Date: Tue Mar 18 2014 - 13:56:23 EST


On 03/15/2014 07:29 PM, Richard Guy Briggs wrote:
> ---
> kernel/audit.c | 5 ++---
> kernel/auditsc.c | 9 +++++----
> 2 files changed, 7 insertions(+), 7 deletions(-)

Doesn't this also need to be fixed (twice) in security/lsm_audit.c?

> diff --git a/kernel/audit.c b/kernel/audit.c
> index 9239e5e..5b600c8 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -1883,7 +1883,7 @@ EXPORT_SYMBOL(audit_log_task_context);
> void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> {
> const struct cred *cred;
> - char name[sizeof(tsk->comm)];
> + char comm[sizeof(tsk->comm)];
> struct mm_struct *mm = tsk->mm;
> char *tty;
>
> @@ -1917,9 +1917,8 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> from_kgid(&init_user_ns, cred->fsgid),
> tty, audit_get_sessionid(tsk));
>
> - get_task_comm(name, tsk);
> audit_log_format(ab, " comm=");
> - audit_log_untrustedstring(ab, name);
> + audit_log_untrustedstring(ab, get_task_comm(name, tsk));
>
> if (mm) {
> down_read(&mm->mmap_sem);
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 8fffca8..b789e0c 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -2289,7 +2289,7 @@ void __audit_ptrace(struct task_struct *t)
> context->target_uid = task_uid(t);
> context->target_sessionid = audit_get_sessionid(t);
> security_task_getsecid(t, &context->target_sid);
> - memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
> + get_task_comm(context->target_comm, t);
> }
>
> /**
> @@ -2328,7 +2328,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
> ctx->target_uid = t_uid;
> ctx->target_sessionid = audit_get_sessionid(t);
> security_task_getsecid(t, &ctx->target_sid);
> - memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
> + get_task_comm(ctx->target_comm, t);
> return 0;
> }
>
> @@ -2349,7 +2349,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
> axp->target_uid[axp->pid_count] = t_uid;
> axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
> security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
> - memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
> + get_task_comm(axp->target_comm[axp->pid_count], t);
> axp->pid_count++;
>
> return 0;
> @@ -2435,6 +2435,7 @@ static void audit_log_task(struct audit_buffer *ab)
> kgid_t gid;
> unsigned int sessionid;
> struct mm_struct *mm = current->mm;
> + char comm[sizeof(current->comm)];
>
> auid = audit_get_loginuid(current);
> sessionid = audit_get_sessionid(current);
> @@ -2447,7 +2448,7 @@ static void audit_log_task(struct audit_buffer *ab)
> sessionid);
> audit_log_task_context(ab);
> audit_log_format(ab, " pid=%d comm=", task_pid_nr(current));
> - audit_log_untrustedstring(ab, current->comm);
> + audit_log_untrustedstring(ab, get_task_comm(comm, current);
> if (mm) {
> down_read(&mm->mmap_sem);
> if (mm->exe_file)
>

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