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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2018-11-02 15:48:42 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-11-03 10:09:38 -0700 |
| commit | 9f2df09a33aa2c76ce6385d382693f98d7f2f07e (patch) | |
| tree | 1a4ccc927a92f7beaddd95b983ad1c2969200908 /fs/bfs/inode.c | |
| parent | 6f0483d1f91b612186abeaebf3ce43bf805eb9f7 (diff) | |
| download | lwn-9f2df09a33aa2c76ce6385d382693f98d7f2f07e.tar.gz lwn-9f2df09a33aa2c76ce6385d382693f98d7f2f07e.zip | |
bfs: add sanity check at bfs_fill_super()
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>
Diffstat (limited to 'fs/bfs/inode.c')
| -rw-r--r-- | fs/bfs/inode.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c index 9a69392f1fb3..d81c148682e7 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); |