net, sunrpc: convert gss_cl_ctx.count from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Reshetova, Elena
2017-07-04 15:53:13 +03:00
committed by David S. Miller
parent 156be7edc8
commit 0fa104726b
2 changed files with 5 additions and 4 deletions

View File

@@ -13,6 +13,7 @@
#define _LINUX_SUNRPC_AUTH_GSS_H #define _LINUX_SUNRPC_AUTH_GSS_H
#ifdef __KERNEL__ #ifdef __KERNEL__
#include <linux/refcount.h>
#include <linux/sunrpc/auth.h> #include <linux/sunrpc/auth.h>
#include <linux/sunrpc/svc.h> #include <linux/sunrpc/svc.h>
#include <linux/sunrpc/gss_api.h> #include <linux/sunrpc/gss_api.h>
@@ -65,7 +66,7 @@ struct rpc_gss_init_res {
* the wire when communicating with a server. */ * the wire when communicating with a server. */
struct gss_cl_ctx { struct gss_cl_ctx {
atomic_t count; refcount_t count;
enum rpc_gss_proc gc_proc; enum rpc_gss_proc gc_proc;
u32 gc_seq; u32 gc_seq;
spinlock_t gc_seq_lock; spinlock_t gc_seq_lock;

View File

@@ -117,14 +117,14 @@ static const struct rpc_pipe_ops gss_upcall_ops_v1;
static inline struct gss_cl_ctx * static inline struct gss_cl_ctx *
gss_get_ctx(struct gss_cl_ctx *ctx) gss_get_ctx(struct gss_cl_ctx *ctx)
{ {
atomic_inc(&ctx->count); refcount_inc(&ctx->count);
return ctx; return ctx;
} }
static inline void static inline void
gss_put_ctx(struct gss_cl_ctx *ctx) gss_put_ctx(struct gss_cl_ctx *ctx)
{ {
if (atomic_dec_and_test(&ctx->count)) if (refcount_dec_and_test(&ctx->count))
gss_free_ctx(ctx); gss_free_ctx(ctx);
} }
@@ -200,7 +200,7 @@ gss_alloc_context(void)
ctx->gc_proc = RPC_GSS_PROC_DATA; ctx->gc_proc = RPC_GSS_PROC_DATA;
ctx->gc_seq = 1; /* NetApp 6.4R1 doesn't accept seq. no. 0 */ ctx->gc_seq = 1; /* NetApp 6.4R1 doesn't accept seq. no. 0 */
spin_lock_init(&ctx->gc_seq_lock); spin_lock_init(&ctx->gc_seq_lock);
atomic_set(&ctx->count,1); refcount_set(&ctx->count,1);
} }
return ctx; return ctx;
} }