3.2.89-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Trond Myklebust <[email protected]> commit 21f498c2f73bd6150d82931f09965826dca0b5f2 upstream. Ensure that the user supplied buffer size doesn't cause us to overflow the 'pages' array. Also fix up some confusion between the use of PAGE_SIZE and PAGE_CACHE_SIZE when calculating buffer sizes. We're not using the page cache for anything here. Signed-off-by: Trond Myklebust <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- fs/nfs/nfs4proc.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3455,11 +3455,11 @@ static inline int nfs4_server_supports_a && (server->acl_bitmask & ACL4_SUPPORT_DENY_ACL); } -/* Assuming that XATTR_SIZE_MAX is a multiple of PAGE_CACHE_SIZE, and that - * it's OK to put sizeof(void) * (XATTR_SIZE_MAX/PAGE_CACHE_SIZE) bytes on +/* Assuming that XATTR_SIZE_MAX is a multiple of PAGE_SIZE, and that + * it's OK to put sizeof(void) * (XATTR_SIZE_MAX/PAGE_SIZE) bytes on * the stack. */ -#define NFS4ACL_MAXPAGES (XATTR_SIZE_MAX >> PAGE_CACHE_SHIFT) +#define NFS4ACL_MAXPAGES DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE) static int buf_to_pages_noslab(const void *buf, size_t buflen, struct page **pages, unsigned int *pgbase) @@ -3470,7 +3470,7 @@ static int buf_to_pages_noslab(const voi spages = pages; do { - len = min_t(size_t, PAGE_CACHE_SIZE, buflen); + len = min_t(size_t, PAGE_SIZE, buflen); newpage = alloc_page(GFP_KERNEL); if (newpage == NULL) @@ -3583,17 +3583,16 @@ static ssize_t __nfs4_get_acl_uncached(s .rpc_argp = &args, .rpc_resp = &res, }; - int ret = -ENOMEM, npages, i; + unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE); + int ret = -ENOMEM, i; size_t acl_len = 0; - npages = (buflen + PAGE_SIZE - 1) >> PAGE_SHIFT; /* As long as we're doing a round trip to the server anyway, * let's be prepared for a page of acl data. */ if (npages == 0) npages = 1; - - /* Add an extra page to handle the bitmap returned */ - npages++; + if (npages > ARRAY_SIZE(pages)) + return -ERANGE; for (i = 0; i < npages; i++) { pages[i] = alloc_page(GFP_KERNEL); @@ -3692,10 +3691,13 @@ static int __nfs4_proc_set_acl(struct in .rpc_argp = &arg, .rpc_resp = &res, }; + unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE); int ret, i; if (!nfs4_server_supports_acls(server)) return -EOPNOTSUPP; + if (npages > ARRAY_SIZE(pages)) + return -ERANGE; i = buf_to_pages_noslab(buf, buflen, arg.acl_pages, &arg.acl_pgbase); if (i < 0) return i;
