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bail out with ELOOP earlier in do_link loop

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If we'd passed through 32 trailing symlinks already, there's
no sense following the 33rd - we'll bail out anyway.  Better
bugger off earlier.

It *does* change behaviour, after a fashion - if the 33rd happens
to be a procfs-style symlink, original code *would* allow it.
This one will not.  Cry me a river if that hurts you.  Please, do.
And post a video of that, while you are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2009-12-24 02:27:30 -05:00
parent a1e28038df
commit c99658fe97
1 changed files with 1 additions and 6 deletions
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7
fs/namei.c
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@ -1873,7 +1873,7 @@ exit_parent:
do_link:
error = -ELOOP;
if (flag & O_NOFOLLOW)
if ((flag & O_NOFOLLOW) || count++ == 32)
goto exit_dput;
/*
* This is subtle. Instead of calling do_follow_link() we do the
@ -1915,11 +1915,6 @@ do_link:
__putname(nd.last.name);
goto exit;
}
error = -ELOOP;
if (count++==32) {
__putname(nd.last.name);
goto exit;
}
filp = do_last(&nd, &path, open_flag, flag, acc_mode, mode,
pathname, &is_link);
__putname(nd.last.name);