f2fs: fix several potential integer overflows in file offsets

commit 1cade98cf6415897bf9342ee451cc5b40b58c638 upstream.

When dealing with large extents and calculating file offsets by
summing up according extent offsets and lengths of unsigned int type,
one may encounter possible integer overflow if the values are
big enough.

Prevent this from happening by expanding one of the addends to
(pgoff_t) type.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: d323d005ac4a ("f2fs: support file defragment")
Cc: stable@vger.kernel.org
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index fd1fc06359eea3e0d67f7cbd88ac3911e4791749..62ac440d94168a452512274209fbf3d57cbbf59a 100644 (file)
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -366,7 +366,7 @@ static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
 static void __drop_largest_extent(struct extent_tree *et,
                                        pgoff_t fofs, unsigned int len)
 {
-       if (fofs < et->largest.fofs + et->largest.len &&
+       if (fofs < (pgoff_t)et->largest.fofs + et->largest.len &&
                        fofs + len > et->largest.fofs) {
                et->largest.len = 0;
                et->largest_updated = true;
@@ -456,7 +456,7 @@ static bool __lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 
        if (type == EX_READ &&
                        et->largest.fofs <= pgofs &&
-                       et->largest.fofs + et->largest.len > pgofs) {
+                       (pgoff_t)et->largest.fofs + et->largest.len > pgofs) {
                *ei = et->largest;
                ret = true;
                stat_inc_largest_node_hit(sbi);

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 5a9c5652776c2c1c17a72ba20f18e3102b2beb45..3ec00b0537f1dbc142408b8021f543fd66557163 100644 (file)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2719,7 +2719,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
         * block addresses are continuous.
         */
        if (f2fs_lookup_read_extent_cache(inode, pg_start, &ei)) {
-               if (ei.fofs + ei.len >= pg_end)
+               if ((pgoff_t)ei.fofs + ei.len >= pg_end)
                        goto out;
        }