Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 5/6] core: allow setrlimit to non-current tasks | Date | Mon, 31 Aug 2009 20:56:13 +0200 |
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Add locking to allow setrlimit accept task parameter other than current.
Namely, lock tasklist_lock for read and check whether the task structure has signal and sighand non-null. Do all the signal processing under that lock still held.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> --- kernel/sys.c | 26 ++++++++++++++++++++------ 1 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/kernel/sys.c b/kernel/sys.c index 919cebe..777a152 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1244,16 +1244,27 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, if (new_rlim->rlim_cur > new_rlim->rlim_max) return -EINVAL; + + /* protect tsk->signal and tsk->sighand from disappearing */ + read_lock_irq(&tasklist_lock); + if (!tsk->signal || !tsk->sighand) { + retval = -ESRCH; + goto unlock; + } old_rlim = tsk->signal->rlim + resource; if ((new_rlim->rlim_max > old_rlim->rlim_max) && - !capable(CAP_SYS_RESOURCE)) - return -EPERM; - if (resource == RLIMIT_NOFILE && new_rlim->rlim_max > sysctl_nr_open) - return -EPERM; + !capable(CAP_SYS_RESOURCE)) { + retval = -EPERM; + goto unlock; + } + if (resource == RLIMIT_NOFILE && new_rlim->rlim_max > sysctl_nr_open) { + retval = -EPERM; + goto unlock; + } retval = security_task_setrlimit(tsk, resource, new_rlim); if (retval) - return retval; + goto unlock; if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { /* @@ -1283,7 +1294,10 @@ int setrlimit(struct task_struct *tsk, unsigned int resource, update_rlimit_cpu(tsk, new_rlim->rlim_cur); out: - return 0; + retval = 0; +unlock: + read_unlock_irq(&tasklist_lock); + return retval; } SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim) -- 1.6.3.3
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