On 15/01/08, Paul Moore wrote:
> There are several areas in the kernel that create temporary filename
> objects using the following pattern:
>
> int func(const char *name)
> {
> struct filename *file = { .name = name };
> ...
> return 0;
> }
>
> ... which for the most part works okay, but it causes havoc within the
> audit subsystem as the filename object does not persist beyond the
> lifetime of the function. This patch converts all of these temporary
> filename objects into proper filename objects using getname_kernel()
> and putname() which ensure that the filename object persists until the
> audit subsystem is finished with it.
>
> Signed-off-by: Paul Moore <pmoore@xxxxxxxxxx>
Reviewed-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> ---
> fs/exec.c | 11 +++++++++--
> fs/namei.c | 34 ++++++++++++++++++++++++++--------
> fs/open.c | 11 +++++++++--
> 3 files changed, 44 insertions(+), 12 deletions(-)
>
> diff --git a/fs/exec.c b/fs/exec.c
> index a3d33fe..d067771 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -789,8 +789,15 @@ exit:
>
> struct file *open_exec(const char *name)
> {
> - struct filename tmp = { .name = name };
> - return do_open_exec(&tmp);
> + struct file *file;
> + struct filename *tmp;
> +
> + tmp = getname_kernel(name);
> + if (unlikely(IS_ERR(tmp)))
> + return (void *)tmp;
> + file = do_open_exec(tmp);
> + putname(tmp);
> + return file;
> }
> EXPORT_SYMBOL(open_exec);
>
> diff --git a/fs/namei.c b/fs/namei.c
> index eeb3b83..c3d21b7 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2001,9 +2001,15 @@ static int filename_lookup(int dfd, struct filename *name,
> static int do_path_lookup(int dfd, const char *name,
> unsigned int flags, struct nameidata *nd)
> {
> - struct filename filename = { .name = name };
> + int retval;
> + struct filename *filename;
>
> - return filename_lookup(dfd, &filename, flags, nd);
> + filename = getname_kernel(name);
> + if (unlikely(IS_ERR(filename)))
> + return PTR_ERR(filename);
> + retval = filename_lookup(dfd, filename, flags, nd);
> + putname(filename);
> + return retval;
> }
>
> /* does lookup, returns the object with parent locked */
> @@ -2368,8 +2374,15 @@ int
> kern_path_mountpoint(int dfd, const char *name, struct path *path,
> unsigned int flags)
> {
> - struct filename s = {.name = name};
> - return filename_mountpoint(dfd, &s, path, flags);
> + int retval;
> + struct filename *s;
> +
> + s = getname_kernel(name);
> + if (unlikely(IS_ERR(s)))
> + return PTR_ERR(s);
> + retval = filename_mountpoint(dfd, s, path, flags);
> + putname(s);
> + return retval;
> }
> EXPORT_SYMBOL(kern_path_mountpoint);
>
> @@ -3259,7 +3272,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
> {
> struct nameidata nd;
> struct file *file;
> - struct filename filename = { .name = name };
> + struct filename *filename;
> int flags = op->lookup_flags | LOOKUP_ROOT;
>
> nd.root.mnt = mnt;
> @@ -3268,11 +3281,16 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
> if (d_is_symlink(dentry) && op->intent & LOOKUP_OPEN)
> return ERR_PTR(-ELOOP);
>
> - file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_RCU);
> + filename = getname_kernel(name);
> + if (unlikely(IS_ERR(filename)))
> + return (void *)filename;
> +
> + file = path_openat(-1, filename, &nd, op, flags | LOOKUP_RCU);
> if (unlikely(file == ERR_PTR(-ECHILD)))
> - file = path_openat(-1, &filename, &nd, op, flags);
> + file = path_openat(-1, filename, &nd, op, flags);
> if (unlikely(file == ERR_PTR(-ESTALE)))
> - file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_REVAL);
> + file = path_openat(-1, filename, &nd, op, flags | LOOKUP_REVAL);
> + putname(filename);
> return file;
> }
>
> diff --git a/fs/open.c b/fs/open.c
> index d6fd3ac..666982b 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -940,8 +940,15 @@ struct file *file_open_name(struct filename *name, int flags, umode_t mode)
> */
> struct file *filp_open(const char *filename, int flags, umode_t mode)
> {
> - struct filename name = {.name = filename};
> - return file_open_name(&name, flags, mode);
> + struct file *file;
> + struct filename *name;
> +
> + name = getname_kernel(filename);
> + if (unlikely(IS_ERR(name)))
> + return (void *)name;
> + file = file_open_name(name, flags, mode);
> + putname(name);
> + return file;
> }
> EXPORT_SYMBOL(filp_open);
>
>
> --
> Linux-audit mailing list
> Linux-audit@xxxxxxxxxx
> https://www.redhat.com/mailman/listinfo/linux-audit
- RGB
--
Richard Guy Briggs <rbriggs@xxxxxxxxxx>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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