[PATCH] f2fs: early check broken symlink length in the encrypted case

From: Jaegeuk Kim
Date: Thu Dec 24 2015 - 20:00:15 EST


If link is broken, its len is zero, and we don't need to move forward.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/namei.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index fb41c80..5cc4128 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -931,7 +931,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
{
struct page *cpage = NULL;
char *caddr, *paddr = NULL;
- struct f2fs_str cstr;
+ struct f2fs_str cstr = FSTR_INIT(NULL, 0);
struct f2fs_str pstr = FSTR_INIT(NULL, 0);
struct inode *inode = d_inode(dentry);
struct f2fs_encrypted_symlink_data *sd;
@@ -952,6 +952,12 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
/* Symlink is encrypted */
sd = (struct f2fs_encrypted_symlink_data *)caddr;
cstr.len = le16_to_cpu(sd->len);
+
+ /* this is broken symlink case */
+ if (cstr.len == 0) {
+ res = -ENOENT;
+ goto errout;
+ }
cstr.name = kmalloc(cstr.len, GFP_NOFS);
if (!cstr.name) {
res = -ENOMEM;
@@ -960,7 +966,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
memcpy(cstr.name, sd->encrypted_path, cstr.len);

/* this is broken symlink case */
- if (cstr.name[0] == 0 && cstr.len == 0) {
+ if (cstr.name[0] == 0) {
res = -ENOENT;
goto errout;
}
--
2.5.4 (Apple Git-61)

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