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| author | Chuck Lever <chuck.lever@oracle.com> | 2011-01-21 03:05:38 +0000 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-01-25 15:24:47 -0500 |
| commit | f61f6da0d53842e849bab7f69e1431bd3de1136d (patch) | |
| tree | 8433904f645695338b98d3dc831631ffd6f129e5 /fs/posix_acl.c | |
| parent | 731f3f482ad3b2c58a1af2d0a9a634a82803706a (diff) | |
| download | lwn-f61f6da0d53842e849bab7f69e1431bd3de1136d.tar.gz lwn-f61f6da0d53842e849bab7f69e1431bd3de1136d.zip | |
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.c | 17 |
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; } |