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authorDavid Howells <dhowells@redhat.com>2009-08-27 13:09:06 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-27 12:22:08 -0700
commit9886e836a6a5dbd273dc55b17e713f0a188d137f (patch)
tree87f8e3d719ae43d5d5d5911d70d6c7b3aa66be32
parent1e23502cc57cef33455ac7cb9111e3c6d991a894 (diff)
downloadlinux-2.6.34-ux500-9886e836a6a5dbd273dc55b17e713f0a188d137f.tar.gz
AFS: Stop readlink() on AFS crashing due to NULL 'file' ptr
kAFS crashes when asked to read a symbolic link because page_getlink() passes a NULL file pointer to read_mapping_page(), but afs_readpage() expects a file pointer from which to extract a key. Modify afs_readpage() to request the appropriate key from the calling process's keyrings if a file struct is not supplied with one attached. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Anton Blanchard <anton@samba.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/afs/file.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 0149dab365e..681c2a7b013 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -134,9 +134,16 @@ static int afs_readpage(struct file *file, struct page *page)
inode = page->mapping->host;
- ASSERT(file != NULL);
- key = file->private_data;
- ASSERT(key != NULL);
+ if (file) {
+ key = file->private_data;
+ ASSERT(key != NULL);
+ } else {
+ key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error_nokey;
+ }
+ }
_enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
@@ -207,12 +214,17 @@ static int afs_readpage(struct file *file, struct page *page)
unlock_page(page);
}
+ if (!file)
+ key_put(key);
_leave(" = 0");
return 0;
error:
SetPageError(page);
unlock_page(page);
+ if (!file)
+ key_put(key);
+error_nokey:
_leave(" = %d", ret);
return ret;
}