ubifs: Don't leak kernel memory to the MTD

commit 4acadda74ff8b949c448c0282765ae747e088c87 upstream.

When UBIFS prepares data structures which will be written to the MTD it
ensues that their lengths are multiple of 8. Since it uses kmalloc() the
padded bytes are left uninitialized and we leak a few bytes of kernel
memory to the MTD.
To make sure that all bytes are initialized, let's switch to kzalloc().
Kzalloc() is fine in this case because the buffers are not huge and in
the IO path the performance bottleneck is anyway the MTD.

Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index 91bc76dc559e2f09d8318e784be8656a1bf33b60..7d764e3b6c795d74598cbe531a201474f8bc611a 100644 (file)
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -576,7 +576,7 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
        /* Make sure to also account for extended attributes */
        len += host_ui->data_len;
 
-       dent = kmalloc(len, GFP_NOFS);
+       dent = kzalloc(len, GFP_NOFS);
        if (!dent)
                return -ENOMEM;
 
@@ -952,7 +952,7 @@ int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
        if (twoparents)
                len += plen;
 
-       dent1 = kmalloc(len, GFP_NOFS);
+       dent1 = kzalloc(len, GFP_NOFS);
        if (!dent1)
                return -ENOMEM;
 
@@ -1102,7 +1102,7 @@ int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
        len = aligned_dlen1 + aligned_dlen2 + ALIGN(ilen, 8) + ALIGN(plen, 8);
        if (move)
                len += plen;
-       dent = kmalloc(len, GFP_NOFS);
+       dent = kzalloc(len, GFP_NOFS);
        if (!dent)
                return -ENOMEM;
 
@@ -1466,7 +1466,7 @@ int ubifs_jnl_delete_xattr(struct ubifs_info *c, const struct inode *host,
        hlen = host_ui->data_len + UBIFS_INO_NODE_SZ;
        len = aligned_xlen + UBIFS_INO_NODE_SZ + ALIGN(hlen, 8);
 
-       xent = kmalloc(len, GFP_NOFS);
+       xent = kzalloc(len, GFP_NOFS);
        if (!xent)
                return -ENOMEM;
 
@@ -1573,7 +1573,7 @@ int ubifs_jnl_change_xattr(struct ubifs_info *c, const struct inode *inode,
        aligned_len1 = ALIGN(len1, 8);
        aligned_len = aligned_len1 + ALIGN(len2, 8);
 
-       ino = kmalloc(aligned_len, GFP_NOFS);
+       ino = kzalloc(aligned_len, GFP_NOFS);
        if (!ino)
                return -ENOMEM;