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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2018-11-02 18:48:42 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-03 13:09:38 -0400
commit9f2df09a33aa2c76ce6385d382693f98d7f2f07e (patch)
tree1a4ccc927a92f7beaddd95b983ad1c2969200908
parent6f0483d1f91b612186abeaebf3ce43bf805eb9f7 (diff)
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>
-rw-r--r--fs/bfs/inode.c9
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)
350 350
351 s->s_magic = BFS_MAGIC; 351 s->s_magic = BFS_MAGIC;
352 352
353 if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) { 353 if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
354 le32_to_cpu(bfs_sb->s_start) < BFS_BSIZE) {
354 printf("Superblock is corrupted\n"); 355 printf("Superblock is corrupted\n");
355 goto out1; 356 goto out1;
356 } 357 }
@@ -359,9 +360,11 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
359 sizeof(struct bfs_inode) 360 sizeof(struct bfs_inode)
360 + BFS_ROOT_INO - 1; 361 + BFS_ROOT_INO - 1;
361 imap_len = (info->si_lasti / 8) + 1; 362 imap_len = (info->si_lasti / 8) + 1;
362 info->si_imap = kzalloc(imap_len, GFP_KERNEL); 363 info->si_imap = kzalloc(imap_len, GFP_KERNEL | __GFP_NOWARN);
363 if (!info->si_imap) 364 if (!info->si_imap) {
365 printf("Cannot allocate %u bytes\n", imap_len);
364 goto out1; 366 goto out1;
367 }
365 for (i = 0; i < BFS_ROOT_INO; i++) 368 for (i = 0; i < BFS_ROOT_INO; i++)
366 set_bit(i, info->si_imap); 369 set_bit(i, info->si_imap);
367 370