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authorRoland McGrath <roland@redhat.com>2010-09-07 19:37:06 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2010-10-28 21:44:17 -0700
commitb9d023fbff9a18a9cd1aa505dc6658e6501028a7 (patch)
tree4e5f73f6523b93121c89d0789222f1102a0b47bc /fs
parentbd720c923f7febe45934f4e87c4c755e45b13bdc (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>
Diffstat (limited to 'fs')
-rw-r--r--fs/exec.c7
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;