52 lines
1.9 KiB
Diff
52 lines
1.9 KiB
Diff
From: Roland McGrath <roland@redhat.com>
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Date: Wed, 8 Sep 2010 02:37:06 +0000 (-0700)
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Subject: execve: make responsive to SIGKILL with large arguments
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X-Git-Tag: v2.6.36-rc4~12
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X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=9aea5a65aa7a1af9a4236dfaeb0088f1624f9919
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execve: make responsive to SIGKILL with large arguments
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An execve with a very large total of argument/environment strings
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can take a really long time in the execve system call. It runs
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uninterruptibly to count and copy all the strings. This change
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makes it abort the exec quickly if sent a SIGKILL.
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Note that this is the conservative change, to interrupt only for
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SIGKILL, by using fatal_signal_pending(). It would be perfectly
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correct semantics to let any signal interrupt the string-copying in
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execve, i.e. use signal_pending() instead of fatal_signal_pending().
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We'll save that change for later, since it could have user-visible
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consequences, such as having a timer set too quickly make it so that
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an execve can never complete, though it always happened to work before.
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Signed-off-by: Roland McGrath <roland@redhat.com>
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Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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diff --git a/fs/exec.c b/fs/exec.c
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index 6f2d777..828dd24 100644
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--- a/fs/exec.c
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+++ b/fs/exec.c
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@@ -376,6 +376,9 @@ static int count(const char __user * const __user * argv, int max)
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argv++;
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if (i++ >= max)
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return -E2BIG;
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+
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+ if (fatal_signal_pending(current))
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+ return -ERESTARTNOHAND;
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cond_resched();
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}
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}
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@@ -419,6 +422,10 @@ static int copy_strings(int argc, const char __user *const __user *argv,
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while (len > 0) {
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int offset, bytes_to_copy;
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+ if (fatal_signal_pending(current)) {
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+ ret = -ERESTARTNOHAND;
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+ goto out;
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+ }
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cond_resched();
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offset = pos % PAGE_SIZE;
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