fs/xattr.c:setxattr(): improve handling of allocation failures

This allocation can be as large as 64k.

 - Add __GFP_NOWARN so the a falied kmalloc() is silent

 - Fall back to vmalloc() if the kmalloc() failed

Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: David Rientjes <rientjes@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 4 deletions

diff --git a/fs/xattr.c b/fs/xattr.c
index d14afbae3c13..3c8c1cc333c7 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -321,6 +321,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
 {
         int error;
         void *kvalue = NULL;
+        void *vvalue = NULL;    /* If non-NULL, we used vmalloc() */
         char kname[XATTR_NAME_MAX + 1];
 
         if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
@@ -335,13 +336,25 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
         if (size) {
                 if (size > XATTR_SIZE_MAX)
                         return -E2BIG;
-                kvalue = memdup_user(value, size);
-                if (IS_ERR(kvalue))
-                        return PTR_ERR(kvalue);
+                kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
+                if (!kvalue) {
+                        vvalue = vmalloc(size);
+                        if (!vvalue)
+                                return -ENOMEM;
+                        kvalue = vvalue;
+                }
+                if (copy_from_user(kvalue, value, size)) {
+                        error = -EFAULT;
+                        goto out;
+                }
         }
 
         error = vfs_setxattr(d, kname, kvalue, size, flags);
-        kfree(kvalue);
+out:
+        if (vvalue)
+                vfree(vvalue);
+        else
+                kfree(kvalue);
         return error;
 }