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authorRoland McGrath <roland@redhat.com>2010-09-07 19:37:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-09-10 08:10:26 -0700
commit9aea5a65aa7a1af9a4236dfaeb0088f1624f9919 (patch)
parent7993bc1f4663c0db67bb8f0d98e6678145b387cd (diff)
execve: make responsive to SIGKILL with large arguments
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> 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 6f2d777431a8..828dd2461d6b 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -376,6 +376,9 @@ static int count(const char __user * const __user * argv, int max)
if (i++ >= max)
return -E2BIG;
+ if (fatal_signal_pending(current))
@@ -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)) {
+ goto out;
+ }
offset = pos % PAGE_SIZE;