diff options
| author | Roland McGrath <roland@redhat.com> | 2010-09-07 19:37:06 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-10-28 21:44:17 -0700 |
| commit | b9d023fbff9a18a9cd1aa505dc6658e6501028a7 (patch) | |
| tree | 4e5f73f6523b93121c89d0789222f1102a0b47bc | |
| parent | bd720c923f7febe45934f4e87c4c755e45b13bdc (diff) | |
execve: make responsive to SIGKILL with large arguments
commit 9aea5a65aa7a1af9a4236dfaeb0088f1624f9919 upstream.
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>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/exec.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c index 775f054f34c7..a0410eb44dfa 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -376,6 +376,9 @@ static int count(char __user * __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, char __user * __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; |