[PATCH] dcache: don't expose uninitialized memory in /proc/<pid>/fd/<fd>

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: J. Bruce Fields <[email protected]>

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 <[email protected]>
---
 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 [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux