3 files changed, 56 insertions, 16 deletions

diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
index 7cde3f46ad26..e996174cbfc0 100644
--- a/fs/binfmt_script.c
+++ b/fs/binfmt_script.c
@@ -14,13 +14,30 @@
 #include <linux/err.h>
 #include <linux/fs.h>
 
+static inline bool spacetab(char c) { return c == ' ' || c == '\t'; }
+static inline char *next_non_spacetab(char *first, const char *last)
+{
+        for (; first <= last; first++)
+                if (!spacetab(*first))
+                        return first;
+        return NULL;
+}
+static inline char *next_terminator(char *first, const char *last)
+{
+        for (; first <= last; first++)
+                if (spacetab(*first) || !*first)
+                        return first;
+        return NULL;
+}
+
 static int load_script(struct linux_binprm *bprm)
 {
         const char *i_arg, *i_name;
-        char *cp;
+        char *cp, *buf_end;
         struct file *file;
         int retval;
 
+        /* Not ours to exec if we don't start with "#!". */
         if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
                 return -ENOEXEC;
 
@@ -33,18 +50,40 @@ static int load_script(struct linux_binprm *bprm)
         if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
                 return -ENOENT;
 
-        /*
-         * This section does the #! interpretation.
-         * Sorta complicated, but hopefully it will work.  -TYT
-         */
-
+        /* Release since we are not mapping a binary into memory. */
         allow_write_access(bprm->file);
         fput(bprm->file);
         bprm->file = NULL;
 
-        bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
-        if ((cp = strchr(bprm->buf, '\n')) == NULL)
-                cp = bprm->buf+BINPRM_BUF_SIZE-1;
+        /*
+         * This section handles parsing the #! line into separate
+         * interpreter path and argument strings. We must be careful
+         * because bprm->buf is not yet guaranteed to be NUL-terminated
+         * (though the buffer will have trailing NUL padding when the
+         * file size was smaller than the buffer size).
+         *
+         * We do not want to exec a truncated interpreter path, so either
+         * we find a newline (which indicates nothing is truncated), or
+         * we find a space/tab/NUL after the interpreter path (which
+         * itself may be preceded by spaces/tabs). Truncating the
+         * arguments is fine: the interpreter can re-read the script to
+         * parse them on its own.
+         */
+        buf_end = bprm->buf + sizeof(bprm->buf) - 1;
+        cp = strnchr(bprm->buf, sizeof(bprm->buf), '\n');
+        if (!cp) {
+                cp = next_non_spacetab(bprm->buf + 2, buf_end);
+                if (!cp)
+                        return -ENOEXEC; /* Entire buf is spaces/tabs */
+                /*
+                 * If there is no later space/tab/NUL we must assume the
+                 * interpreter path is truncated.
+                 */
+                if (!next_terminator(cp, buf_end))
+                        return -ENOEXEC;
+                cp = buf_end;
+        }
+        /* NUL-terminate the buffer and any trailing spaces/tabs. */
         *cp = '\0';
         while (cp > bprm->buf) {
                 cp--;
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index f12cb31a41e5..d09c9f878141 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -238,9 +238,9 @@ out:
 }
 
 /* A writeback failed: mark the page as bad, and invalidate the page cache */
-static void nfs_set_pageerror(struct page *page)
+static void nfs_set_pageerror(struct address_space *mapping)
 {
-        nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
+        nfs_zap_mapping(mapping->host, mapping);
 }
 
 /*
@@ -994,7 +994,7 @@ static void nfs_write_completion(struct nfs_pgio_header *hdr)
                 nfs_list_remove_request(req);
                 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
                     (hdr->good_bytes < bytes)) {
-                        nfs_set_pageerror(req->wb_page);
+                        nfs_set_pageerror(page_file_mapping(req->wb_page));
                         nfs_context_set_write_error(req->wb_context, hdr->error);
                         goto remove_req;
                 }
@@ -1348,7 +1348,8 @@ int nfs_updatepage(struct file *file, struct page *page,
                 unsigned int offset, unsigned int count)
 {
         struct nfs_open_context *ctx = nfs_file_open_context(file);
-        struct inode    *inode = page_file_mapping(page)->host;
+        struct address_space *mapping = page_file_mapping(page);
+        struct inode    *inode = mapping->host;
         int             status = 0;
 
         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
@@ -1366,7 +1367,7 @@ int nfs_updatepage(struct file *file, struct page *page,
 
         status = nfs_writepage_setup(ctx, page, offset, count);
         if (status < 0)
-                nfs_set_pageerror(page);
+                nfs_set_pageerror(mapping);
         else
                 __set_page_dirty_nobuffers(page);
 out:
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index b33f9785b756..72a7681f4046 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1239,8 +1239,8 @@ static __net_init int nfsd_init_net(struct net *net)
         retval = nfsd_idmap_init(net);
         if (retval)
                 goto out_idmap_error;
-        nn->nfsd4_lease = 45;   /* default lease time */
-        nn->nfsd4_grace = 45;
+        nn->nfsd4_lease = 90;   /* default lease time */
+        nn->nfsd4_grace = 90;
         nn->somebody_reclaimed = false;
         nn->clverifier_counter = prandom_u32();
         nn->clientid_counter = prandom_u32();