[PATCH 4.14 111/157] UBIFS: Fix potential integer overflow in allocation

From: Greg Kroah-Hartman
Date: Sun Jul 01 2018 - 12:36:29 EST

4.14-stable review patch. If anyone has any objections, please let me know.


From: Silvio Cesare <silvio.cesare@xxxxxxxxx>

commit 353748a359f1821ee934afc579cf04572406b420 upstream.

There is potential for the size and len fields in ubifs_data_node to be
too large causing either a negative value for the length fields or an
integer overflow leading to an incorrect memory allocation. Likewise,
when the len field is small, an integer underflow may occur.

Signed-off-by: Silvio Cesare <silvio.cesare@xxxxxxxxx>
Fixes: 1e51764a3c2ac ("UBIFS: add new flash file system")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

fs/ubifs/journal.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -1283,10 +1283,11 @@ static int truncate_data_node(const stru
int *new_len)
void *buf;
- int err, dlen, compr_type, out_len, old_dlen;
+ int err, compr_type;
+ u32 dlen, out_len, old_dlen;

out_len = le32_to_cpu(dn->size);
- buf = kmalloc(out_len * WORST_COMPR_FACTOR, GFP_NOFS);
+ buf = kmalloc_array(out_len, WORST_COMPR_FACTOR, GFP_NOFS);
if (!buf)
return -ENOMEM;