| From 9f2df09a33aa2c76ce6385d382693f98d7f2f07e Mon Sep 17 00:00:00 2001 |
| From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> |
| Date: Fri, 2 Nov 2018 15:48:42 -0700 |
| Subject: bfs: add sanity check at bfs_fill_super() |
| |
| From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> |
| |
| commit 9f2df09a33aa2c76ce6385d382693f98d7f2f07e upstream. |
| |
| 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 |
| |
| Link: http://lkml.kernel.org/r/1525862104-3407-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp |
| Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> |
| Reported-by: syzbot <syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com> |
| Reviewed-by: Andrew Morton <akpm@linux-foundation.org> |
| Cc: Tigran Aivazian <aivazian.tigran@gmail.com> |
| Cc: Matthew Wilcox <willy@infradead.org> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/bfs/inode.c | 9 ++++++--- |
| 1 file changed, 6 insertions(+), 3 deletions(-) |
| |
| --- a/fs/bfs/inode.c |
| +++ b/fs/bfs/inode.c |
| @@ -350,7 +350,8 @@ static int bfs_fill_super(struct super_b |
| |
| 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_b |
| 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); |
| |
