Messages in this thread Patch in this message | | | Date | Tue, 16 Oct 2007 15:35:57 -0400 | Subject | [PATCH] dcache: don't expose uninitialized memory in /proc/<pid>/fd/<fd> | From | "J. Bruce Fields" <> |
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From: J. Bruce Fields <bfields@citi.umich.edu>
Well, it's not especially important that target->d_iname get the contents of dentry->d_iname, but it's important that it get initialized with *something*, otherwise we're just exposing some random piece of memory to anyone who reads the link at /proc/<pid>/fd/<fd> for the deleted file, when it's still held open by someone.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> --- fs/dcache.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
(Am I missing something? I've also run a test program that copies a short (<36 character) name ontop of a long (>=36 character) name and see that the first time I run it, without this patch, I get unpredicatable results out of /proc/<pid>/fd/<fd>.)
diff --git a/fs/dcache.c b/fs/dcache.c index 5663a31..24252fc 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1483,6 +1483,8 @@ static void switch_names(struct dentry *dentry, struct dentry *target) * dentry:internal, target:external. Steal target's * storage and make target internal. */ + memcpy(target->d_iname, dentry->d_name.name, + dentry->d_name.len + 1); dentry->d_name.name = target->d_name.name; target->d_name.name = target->d_iname; } -- 1.5.3.4.208.gc990 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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