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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 21:04:19 -0700
commit358b1c7959f05070c270c00bf2b1bcba8eb4b6b5 (patch)
parent7a6c02774aa7ff340d3b69c941ccd2ec2b3bbd73 (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>
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c
index b89ac31d53d5..fc30de0d1215 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -393,6 +393,9 @@ static int count(char __user * __user * argv, int max)
if(++i > max)
return -E2BIG;
+ if (fatal_signal_pending(current))
@@ -436,6 +439,10 @@ static int copy_strings(int argc, char __user * __user * argv,
while (len > 0) {
int offset, bytes_to_copy;
+ if (fatal_signal_pending(current)) {
+ goto out;
+ }
offset = pos % PAGE_SIZE;