From patchwork Thu May 31 17:00:59 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [2/2, CVE-2012-2375, PRECISE] Avoid beyond bounds copy while caching ACL Date: Thu, 31 May 2012 07:00:59 -0000 From: Brad Figg X-Patchwork-Id: 162189 Message-Id: <1338483659-5583-3-git-send-email-brad.figg@canonical.com> To: kernel-team@lists.ubuntu.com From: Sachin Prabhu CVE-2012-2375 When attempting to cache ACLs returned from the server, if the bitmap size + the ACL size is greater than a PAGE_SIZE but the ACL size itself is smaller than a PAGE_SIZE, we can read past the buffer page boundary. Signed-off-by: Sachin Prabhu Reported-by: Jian Li Signed-off-by: Trond Myklebust (backported from commit 5794d21ef4639f0e33440927bb903f9598c21e92 upstream) Signed-off-by: Brad Figg --- fs/nfs/nfs4proc.c | 12 +++++------- fs/nfs/nfs4xdr.c | 2 +- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 1e2a661..4fbb771 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3525,16 +3525,16 @@ out: return ret; } -static void nfs4_write_cached_acl(struct inode *inode, const char *buf, size_t acl_len) +static void nfs4_write_cached_acl(struct inode *inode, struct page **pages, size_t pgbase, size_t acl_len) { struct nfs4_cached_acl *acl; - if (buf && acl_len <= PAGE_SIZE) { + if (pages && acl_len <= PAGE_SIZE) { acl = kmalloc(sizeof(*acl) + acl_len, GFP_KERNEL); if (acl == NULL) goto out; acl->cached = 1; - memcpy(acl->data, buf, acl_len); + _copy_from_pages(acl->data, pages, pgbase, acl_len); } else { acl = kmalloc(sizeof(*acl), GFP_KERNEL); if (acl == NULL) @@ -3567,7 +3567,6 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu struct nfs_getaclres res = { .acl_len = buflen, }; - void *resp_buf; struct rpc_message msg = { .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETACL], .rpc_argp = &args, @@ -3602,7 +3601,6 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu * the page we send as a guess */ if (buf == NULL) res.acl_flags |= NFS4_ACL_LEN_REQUEST; - resp_buf = page_address(pages[0]); dprintk("%s buf %p buflen %ld npages %d args.acl_len %ld\n", __func__, buf, buflen, npages, args.acl_len); @@ -3613,9 +3611,9 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu acl_len = res.acl_len - res.acl_data_offset; if (acl_len > args.acl_len) - nfs4_write_cached_acl(inode, NULL, acl_len); + nfs4_write_cached_acl(inode, NULL, 0, acl_len); else - nfs4_write_cached_acl(inode, resp_buf + res.acl_data_offset, + nfs4_write_cached_acl(inode, pages, res.acl_data_offset, acl_len); if (buf) { ret = -ERANGE; diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index d7e6f7b..bdd5bdc 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c @@ -5003,7 +5003,7 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req, res->acl_len = attrlen; goto out; } - dprintk("NFS: acl reply: attrlen %zu > page_len %u\n", + dprintk("NFS: acl reply: attrlen %u > page_len %zu\n", attrlen, page_len); return -EINVAL; }