From: Shigeru Yoshida syoshida@redhat.com
[ Upstream commit caad9dd8792a2622737b7273cb34835fd9536cd2 ]
syzbot reported UBSAN error as below:
[ 76.901829][ T6677] ================================================================================ [ 76.903908][ T6677] UBSAN: shift-out-of-bounds in fs/ntfs3/super.c:675:13 [ 76.905363][ T6677] shift exponent -247 is negative
This patch avoid this error.
Link: https://syzkaller.appspot.com/bug?id=b0299c09a14aababf0f1c862dd4ebc8ab9eb017... Fixes: a3b774342fa7 (fs/ntfs3: validate BOOT sectors_per_clusters) Cc: Author: Randy Dunlap rdunlap@infradead.org Reported-by: syzbot+35b87c668935bb55e666@syzkaller.appspotmail.com Signed-off-by: Shigeru Yoshida syoshida@redhat.com Signed-off-by: Konstantin Komarov almaz.alexandrovich@paragon-software.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ntfs3/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c index 47012c9bf505..adc4f73722b7 100644 --- a/fs/ntfs3/super.c +++ b/fs/ntfs3/super.c @@ -672,7 +672,7 @@ static u32 true_sectors_per_clst(const struct NTFS_BOOT *boot) if (boot->sectors_per_clusters <= 0x80) return boot->sectors_per_clusters; if (boot->sectors_per_clusters >= 0xf4) /* limit shift to 2MB max */ - return 1U << (0 - boot->sectors_per_clusters); + return 1U << -(s8)boot->sectors_per_clusters; return -EINVAL; }