posix_acl: fix reference leaks in posix_acl_create

Commit Message

Omar Sandoval Feb. 2, 2015, 7:55 a.m. UTC

On Wed, Jan 28, 2015 at 06:09:52PM +0100, Christoph Hellwig wrote:
> On Mon, Jan 26, 2015 at 10:16:53PM -0800, Omar Sandoval wrote:
> > get_acl gets a reference which we must release in the error cases.
> > 
> > Signed-off-by: Omar Sandoval <[e-mail]>
> 
> Looks good, but at this point goto-based unwinding might be in order.

Hi, Christoph,

There are already a couple of return paths in posix_acl_create, and
there are only these two error cases, so I think gotos might actually
make the code more confusing. In any case, here's an idea:

posix_acl: fix reference leaks in posix_acl_create

get_acl gets a reference which we must release in the error cases.

Signed-off-by: Omar Sandoval <[e-mail]>

Comments

Christoph Hellwig Feb. 2, 2015, 2:19 p.m. UTC | #1

On Sun, Feb 01, 2015 at 11:55:02PM -0800, Omar Sandoval wrote:
> There are already a couple of return paths in posix_acl_create, and
> there are only these two error cases, so I think gotos might actually
> make the code more confusing. In any case, here's an idea:
> 
> posix_acl: fix reference leaks in posix_acl_create
> 
> get_acl gets a reference which we must release in the error cases.
> 
> Signed-off-by: Omar Sandoval <[e-mail]>

Thanks, this one looks good to me.

Reviewed-by: Christoph Hellwig <[e-mail]>
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Patch

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 0855f77..515d315 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -564,13 +564,11 @@  posix_acl_create(struct inode *dir, umode_t *mode,

        *acl = posix_acl_clone(p, GFP_NOFS);
        if (!*acl)
-               return -ENOMEM;
+               goto no_mem;

        ret = posix_acl_create_masq(*acl, mode);
-       if (ret < 0) {
-               posix_acl_release(*acl);
-               return -ENOMEM;
-       }
+       if (ret < 0)
+               goto no_mem_clone;

        if (ret == 0) {
                posix_acl_release(*acl);
@@ -591,6 +589,12 @@  no_acl:
        *default_acl = NULL;
        *acl = NULL;
        return 0;
+
+no_mem_clone:
+       posix_acl_release(*acl);
+no_mem:
+       posix_acl_release(p);
+       return -ENOMEM;
 }
 EXPORT_SYMBOL_GPL(posix_acl_create);