All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] bfs: add sanity check at bfs_fill_super().
@ 2018-05-09 10:35 Tetsuo Handa
  2018-05-09 23:06 ` Andrew Morton
  2018-05-10  0:53 ` Matthew Wilcox
  0 siblings, 2 replies; 21+ messages in thread
From: Tetsuo Handa @ 2018-05-09 10:35 UTC (permalink / raw)
  To: akpm; +Cc: linux-fsdevel, Tetsuo Handa, Tigran Aivazian, syzbot

syzbot is reporting too large memory allocation at bfs_fill_super() [1].
Since file system image is corrupted such that bfs_sb->s_start == 0,
bfs_fill_super() is trying to allocate 8MB of continuous memory. Fix this
by adding a sanity check on bfs_sb->s_start, __GFP_NOWARN and printf().

[1] https://syzkaller.appspot.com/bug?id=16a87c236b951351374a84c8a32f40edbc034e96

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com>
Cc: Tigran Aivazian <aivazian.tigran@gmail.com>
---
 fs/bfs/inode.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index 9a69392..d81c148 100644
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -350,7 +350,8 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 
 	s->s_magic = BFS_MAGIC;
 
-	if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) {
+	if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
+	    le32_to_cpu(bfs_sb->s_start) < BFS_BSIZE) {
 		printf("Superblock is corrupted\n");
 		goto out1;
 	}
@@ -359,9 +360,11 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 					sizeof(struct bfs_inode)
 					+ BFS_ROOT_INO - 1;
 	imap_len = (info->si_lasti / 8) + 1;
-	info->si_imap = kzalloc(imap_len, GFP_KERNEL);
-	if (!info->si_imap)
+	info->si_imap = kzalloc(imap_len, GFP_KERNEL | __GFP_NOWARN);
+	if (!info->si_imap) {
+		printf("Cannot allocate %u bytes\n", imap_len);
 		goto out1;
+	}
 	for (i = 0; i < BFS_ROOT_INO; i++)
 		set_bit(i, info->si_imap);
 
-- 
1.8.3.1

^ permalink raw reply related	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2018-06-15 10:45 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-05-09 10:35 [PATCH] bfs: add sanity check at bfs_fill_super() Tetsuo Handa
2018-05-09 23:06 ` Andrew Morton
     [not found]   ` <201805092346.w49NkINl045657@www262.sakura.ne.jp>
2018-05-09 23:53     ` Andrew Morton
2018-06-13 13:33       ` Tetsuo Handa
2018-06-13 13:49         ` Tigran Aivazian
2018-06-13 16:00           ` Dmitry Vyukov
2018-06-14 12:23             ` Tigran Aivazian
2018-06-14 12:38               ` Dmitry Vyukov
2018-06-14 13:05                 ` Tigran Aivazian
2018-06-14 13:12                   ` Dmitry Vyukov
2018-06-14 13:28                   ` Tetsuo Handa
2018-06-14 15:13                     ` Tigran Aivazian
2018-06-14 16:15                       ` Tigran Aivazian
2018-06-14 19:00                         ` Tigran Aivazian
2018-06-14 22:18                           ` Tetsuo Handa
2018-06-15 10:45                             ` Tigran Aivazian
2018-06-13 22:09           ` Tetsuo Handa
2018-06-14  7:38             ` Tigran Aivazian
2018-06-14 10:45               ` Tetsuo Handa
2018-06-14 12:11                 ` Tigran Aivazian
2018-05-10  0:53 ` Matthew Wilcox

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.