oss-sec mailing list archives
[PATCH 3/3] execve: make responsive to SIGKILL with large arguments
From: Roland McGrath <roland () redhat com>
Date: Tue, 7 Sep 2010 19:37:06 -0700 (PDT)
An execve with a very large total of argument/environment strings can take a really long time in the execve system call. It runs uninterruptibly to count and copy all the strings. This change makes it abort the exec quickly if sent a SIGKILL. Note that this is the conservative change, to interrupt only for SIGKILL, by using fatal_signal_pending(). It would be perfectly correct semantics to let any signal interrupt the string-copying in execve, i.e. use signal_pending() instead of fatal_signal_pending(). We'll save that change for later, since it could have user-visible consequences, such as having a timer set too quickly make it so that an execve can never complete, though it always happened to work before. Signed-off-by: Roland McGrath <roland () redhat com> --- fs/exec.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 6f2d777..828dd24 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -376,6 +376,9 @@ static int count(const char __user * const __user * argv, int max) argv++; if (i++ >= max) return -E2BIG; + + if (fatal_signal_pending(current)) + return -ERESTARTNOHAND; cond_resched(); } } @@ -419,6 +422,10 @@ static int copy_strings(int argc, const char __user *const __user *argv, while (len > 0) { int offset, bytes_to_copy; + if (fatal_signal_pending(current)) { + ret = -ERESTARTNOHAND; + goto out; + } cond_resched(); offset = pos % PAGE_SIZE;
Current thread:
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size, (continued)
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size Roland McGrath (Sep 14)
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size pageexec (Sep 14)
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size Roland McGrath (Sep 14)
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size pageexec (Sep 15)
- Message not available
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size Roland McGrath (Sep 10)
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size pageexec (Sep 11)
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size Roland McGrath (Sep 14)
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size pageexec (Sep 14)
- Message not available
- Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size Roland McGrath (Sep 10)
- [PATCH 2/3] execve: improve interactivity with large arguments Roland McGrath (Sep 07)
- [PATCH 3/3] execve: make responsive to SIGKILL with large arguments Roland McGrath (Sep 07)
- Re: [PATCH 0/3] execve argument-copying fixes KOSAKI Motohiro (Sep 07)
- [PATCH 0/2] execve memory exhaust of argument-copying fixes KOSAKI Motohiro (Sep 09)
- [PATCH 1/2] oom: don't ignore rss in nascent mm KOSAKI Motohiro (Sep 09)
- Message not available
- Re: [PATCH 1/2] oom: don't ignore rss in nascent mm Roland McGrath (Sep 10)
- Message not available
- [PATCH] move cred_guard_mutex from task_struct to signal_struct KOSAKI Motohiro (Sep 10)
- Re: [PATCH] move cred_guard_mutex from task_struct to signal_struct Oleg Nesterov (Sep 10)
- Re: [PATCH] move cred_guard_mutex from task_struct to signal_struct KOSAKI Motohiro (Sep 15)
- [PATCH 2/2] execve: check the VM has enough memory at first KOSAKI Motohiro (Sep 09)
- Re: [PATCH 2/2] execve: check the VM has enough memory at first Linus Torvalds (Sep 10)
- Re: [PATCH 2/2] execve: check the VM has enough memory at first KOSAKI Motohiro (Sep 13)