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authorChuck Lever <chuck.lever@oracle.com>2011-01-21 03:05:38 +0000
committerTrond Myklebust <Trond.Myklebust@netapp.com>2011-01-25 15:24:47 -0500
commitf61f6da0d53842e849bab7f69e1431bd3de1136d (patch)
tree8433904f645695338b98d3dc831631ffd6f129e5 /fs/posix_acl.c
parent731f3f482ad3b2c58a1af2d0a9a634a82803706a (diff)
NFS: Prevent memory allocation failure in nfsacl_encode()
nfsacl_encode() allocates memory in certain cases. This of course is not guaranteed to work. Since commit 9f06c719 "SUNRPC: New xdr_streams XDR encoder API", the kernel's XDR encoders can't return a result indicating possibly a failure, so a memory allocation failure in nfsacl_encode() has become fatal (ie, the XDR code Oopses) in some cases. However, the allocated memory is a tiny fixed amount, on the order of 40-50 bytes. We can easily use a stack-allocated buffer for this, with only a wee bit of nose-holding. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/posix_acl.c')
-rw-r--r--fs/posix_acl.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 39df95a0ec25..b1cf6bf4b41d 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -22,6 +22,7 @@
#include <linux/errno.h>
+EXPORT_SYMBOL(posix_acl_init);
EXPORT_SYMBOL(posix_acl_alloc);
EXPORT_SYMBOL(posix_acl_clone);
EXPORT_SYMBOL(posix_acl_valid);
@@ -32,6 +33,16 @@ EXPORT_SYMBOL(posix_acl_chmod_masq);
EXPORT_SYMBOL(posix_acl_permission);
/*
+ * Init a fresh posix_acl
+ */
+void
+posix_acl_init(struct posix_acl *acl, int count)
+{
+ atomic_set(&acl->a_refcount, 1);
+ acl->a_count = count;
+}
+
+/*
* Allocate a new ACL with the specified number of entries.
*/
struct posix_acl *
@@ -40,10 +51,8 @@ posix_acl_alloc(int count, gfp_t flags)
const size_t size = sizeof(struct posix_acl) +
count * sizeof(struct posix_acl_entry);
struct posix_acl *acl = kmalloc(size, flags);
- if (acl) {
- atomic_set(&acl->a_refcount, 1);
- acl->a_count = count;
- }
+ if (acl)
+ posix_acl_init(acl, count);
return acl;
}