On a 32-bit system, below calculation may overflow the 32-bit unsigned
integer, allocating a buffer size that smaller than needed. A write on
the buffer will then trigger an out of boundary write.
1. MAIN_SEGS(sbi) * sizeof(struct seg_entry)
2. MAIN_SECS(sbi) * sizeof(struct sec_entry)
Fixes this by doing type cast before calculating.
This patch fixes CVE-2017-10662.
Signed-off-by: Chao Yu <yuch...@huawei.com>
---
fs/f2fs/segment.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 682ae68b9ef7..947674b5f466 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2997,8 +2997,9 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
SM_I(sbi)->sit_info = sit_i;
- sit_i->sentries = kvzalloc(MAIN_SEGS(sbi) *
- sizeof(struct seg_entry), GFP_KERNEL);
+ sit_i->sentries = kvzalloc((unsigned long long)MAIN_SEGS(sbi) *
+ (unsigned long long)sizeof(struct seg_entry),
+ GFP_KERNEL);
if (!sit_i->sentries)
return -ENOMEM;
@@ -3036,8 +3037,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
return -ENOMEM;
if (sbi->segs_per_sec > 1) {
- sit_i->sec_entries = kvzalloc(MAIN_SECS(sbi) *
- sizeof(struct sec_entry), GFP_KERNEL);
+ sit_i->sec_entries = kvzalloc(
+ (unsigned long long)MAIN_SECS(sbi) *
+ (unsigned long long)sizeof(struct sec_entry),
+ GFP_KERNEL);
if (!sit_i->sec_entries)
return -ENOMEM;
}
--
2.13.1.388.g69e6b9b4f4a9
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
