Messages in this thread Patch in this message | | | From | Dongliang Mu <> | Subject | [PATCH] fs: jfs: fix shift-out-of-bounds in dbAllocAG | Date | Thu, 29 Sep 2022 13:44:59 +0800 |
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From: Dongliang Mu <mudongliangabcd@gmail.com>
Syzbot found a crash : UBSAN: shift-out-of-bounds in dbAllocAG. The underlying bug is the missing check of bmp->db_agl2size. The field can be greater than 32 and trigger the shift-out-of-bounds.
Fix this bug by adding a check of bmp->db_agl2size in dbMount since this field is used in many following functions. Note that, for maintainance, I reorganzie the error handling code of dbMount.
Reported-by: syzbot+15342c1aa6a00fb7a438@syzkaller.appspotmail.com Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> --- fs/jfs/jfs_dmap.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 6b838d3ae7c2..4c717f245920 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -155,7 +155,7 @@ int dbMount(struct inode *ipbmap) struct bmap *bmp; struct dbmap_disk *dbmp_le; struct metapage *mp; - int i; + int i, err; /* * allocate/initialize the in-memory bmap descriptor @@ -170,8 +170,8 @@ int dbMount(struct inode *ipbmap) BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage, PSIZE, 0); if (mp == NULL) { - kfree(bmp); - return -EIO; + err = -EIO; + goto err_kfree_bmp; } /* copy the on-disk bmap descriptor to its in-memory version. */ @@ -181,9 +181,8 @@ int dbMount(struct inode *ipbmap) bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage); bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag); if (!bmp->db_numag) { - release_metapage(mp); - kfree(bmp); - return -EINVAL; + err = -EINVAL; + goto err_release_metapage; } bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel); @@ -194,6 +193,10 @@ int dbMount(struct inode *ipbmap) bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth); bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart); bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size); + if (bmp->db_agl2size >= 32) { + err = -EINVAL; + goto err_release_metapage; + } for (i = 0; i < MAXAG; i++) bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]); bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize); @@ -214,6 +217,12 @@ int dbMount(struct inode *ipbmap) BMAP_LOCK_INIT(bmp); return (0); + +err_release_metapage: + release_metapage(mp); +err_kfree_bmp: + kfree(bmp); + return err; } -- 2.35.1
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