From: Jan Kara Date: Sat, 6 Apr 2019 22:33:06 +0000 (-0400) Subject: ext4: make sanity check in mballoc more strict X-Git-Tag: v5.0.18~39 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7dfca4b97693ab8ae4a0953c0bd2be0b33f56f2e;p=thirdparty%2Fkernel%2Fstable.git ext4: make sanity check in mballoc more strict commit 31562b954b60f02acb91b7349dc6432d3f8c3c5f upstream. The sanity check in mb_find_extent() only checked that returned extent does not extend past blocksize * 8, however it should not extend past EXT4_CLUSTERS_PER_GROUP(sb). This can happen when clusters_per_group < blocksize * 8 and the tail of the bitmap is not properly filled by 1s which happened e.g. when ancient kernels have grown the filesystem. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index e2248083cdcae..459450e59a884 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1539,7 +1539,7 @@ static int mb_find_extent(struct ext4_buddy *e4b, int block, ex->fe_len += 1 << order; } - if (ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3))) { + if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) { /* Should never happen! (but apparently sometimes does?!?) */ WARN_ON(1); ext4_error(e4b->bd_sb, "corruption or bug in mb_find_extent "