binary_sysctl(): fix memory leak

binary_sysctl() calls sysctl_getname() which allocates from names_cache
slab usin __getname()

The matching function to free the name is __putname(), and not putname()
which should be used only to match getname() allocations.

This is because when auditing is enabled, putname() calls audit_putname
*instead* (not in addition) to __putname().  Then, if a syscall is in
progress, audit_putname does not release the name - instead, it expects
the name to get released when the syscall completes, but that will happen
only if audit_getname() was called previously, i.e.  if the name was
allocated with getname() rather than the naked __getname().  So,
__getname() followed by putname() ends up leaking memory.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 6318b511afa10b3044c7bbd1eb49b28f7c490fcc..a650694883a180e93c5ec1d6414e45ba904fcff3 100644 (file)
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1354,7 +1354,7 @@ static ssize_t binary_sysctl(const int *name, int nlen,
 
        fput(file);
 out_putname:
-       putname(pathname);
+       __putname(pathname);
 out:
        return result;
 }