On Tue, 13 Nov 2018 at 05:52, Sasha Levin <sashal@xxxxxxxxxx> wrote: > 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 Hi Sasha, Thank you, but no, I am rejecting this patch as I have already submitted a much more robust and accurate (stronger check) patch to Andrew Morton a couple of days ago against 4.20-rc1. Andrew, if you would like me to make the same patch against 4.19.1 as well, please let me know. Kind regards, Tigran > > Link: http://lkml.kernel.org/r/1525862104-3407-1-git-send-email-penguin-kernel@xxxxxxxxxxxxxxxxxxx > Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> > Reported-by: syzbot <syzbot+71c6b5d68e91149fc8a4@xxxxxxxxxxxxxxxxxxxxxxxxx> > Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Tigran Aivazian <aivazian.tigran@xxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > 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 90bc079d9982..0ee38b284ad7 100644 > --- a/fs/bfs/inode.c > +++ b/fs/bfs/inode.c > @@ -349,7 +349,8 @@ 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; > } > @@ -358,9 +359,11 @@ 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); > > -- > 2.17.1 >
