From d4137251f8d762dc3469cd92cff7c66fce3752a9 Mon Sep 17 00:00:00 2001 From: Timo Warns Date: Tue, 13 Sep 2011 16:21:26 +0100 Subject: [PATCH] befs: Validate length of long symbolic links, CVE-2011-2928 Signed-off-by: Timo Warns Signed-off-by: Linus Torvalds (cherry picked from commit 338d0f0a6fbc82407864606f5b64b75aeb3c70f2) CVE-2011-2928 BugLink: http://bugs.launchpad.net/bugs/834124 Signed-off-by: Andy Whitcroft Signed-off-by: Tim Gardner --- fs/befs/linuxvfs.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c index b1d0c79..e8ff0d7 100644 --- a/fs/befs/linuxvfs.c +++ b/fs/befs/linuxvfs.c @@ -475,17 +475,22 @@ befs_follow_link(struct dentry *dentry, struct nameidata *nd) befs_data_stream *data = &befs_ino->i_data.ds; befs_off_t len = data->size; - befs_debug(sb, "Follow long symlink"); - - link = kmalloc(len, GFP_NOFS); - if (!link) { - link = ERR_PTR(-ENOMEM); - } else if (befs_read_lsymlink(sb, data, link, len) != len) { - kfree(link); - befs_error(sb, "Failed to read entire long symlink"); + if (len == 0) { + befs_error(sb, "Long symlink with illegal length"); link = ERR_PTR(-EIO); } else { - link[len - 1] = '\0'; + befs_debug(sb, "Follow long symlink"); + + link = kmalloc(len, GFP_NOFS); + if (!link) { + link = ERR_PTR(-ENOMEM); + } else if (befs_read_lsymlink(sb, data, link, len) != len) { + kfree(link); + befs_error(sb, "Failed to read entire long symlink"); + link = ERR_PTR(-EIO); + } else { + link[len - 1] = '\0'; + } } } else { link = befs_ino->i_data.symlink; -- 1.7.10.4