diff options
| author | Theo de Raadt <deraadt@cvs.openbsd.org> | 2009-05-15 01:57:17 +0000 |
|---|---|---|
| committer | Theo de Raadt <deraadt@cvs.openbsd.org> | 2009-05-15 01:57:17 +0000 |
| commit | ff9da047942c85af7190cee3beaaa678a8ceb800 (patch) | |
| tree | 4e2ffb9635a12564cfdc707d572d4e71e291796d | |
| parent | 2d24c9a96a160b4ef64056571be065e54741c9f1 (diff) | |
Validate the main MBR minimally; if it does not have the AA55 thingy we must
not read garbage values as partitions... which we then put into the spoofed
label... and which would lead disklabel -A to make surprising decisions.
earlier versions which did too much validation tested by many
| -rw-r--r-- | sys/kern/subr_disk.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c index a42e3e3ba09..65707d76ba9 100644 --- a/sys/kern/subr_disk.c +++ b/sys/kern/subr_disk.c @@ -1,4 +1,4 @@ -/* $OpenBSD: subr_disk.c,v 1.87 2009/05/13 01:14:19 deraadt Exp $ */ +/* $OpenBSD: subr_disk.c,v 1.88 2009/05/15 01:57:16 deraadt Exp $ */ /* $NetBSD: subr_disk.c,v 1.17 1996/03/16 23:17:08 christos Exp $ */ /* @@ -415,6 +415,16 @@ readdoslabel(struct buf *bp, void (*strat)(struct buf *), bcopy(bp->b_data + offset, dp, sizeof(dp)); + if (n == 0 && part_blkno == DOSBBSECTOR) { + u_int16_t fattest; + + /* Check the end of sector marker. */ + fattest = ((bp->b_data[510] << 8) & 0xff00) | + (bp->b_data[511] & 0xff); + if (fattest != 0x55aa) + goto notfat; + } + if (ourpart == -1) { /* Search for our MBR partition */ for (dp2=dp, i=0; i < NDOSPART && ourpart == -1; @@ -554,12 +564,6 @@ donot: if (fattest < 512 || fattest > 4096 || (fattest % 512 != 0)) goto notfat; - /* Check the end of sector marker. */ - fattest = ((bp->b_data[510] << 8) & 0xff00) | - (bp->b_data[511] & 0xff); - if (fattest != 0x55aa) - goto notfat; - /* Looks like a FAT filesystem. Spoof 'i'. */ DL_SETPSIZE(&lp->d_partitions['i' - 'a'], DL_GETPSIZE(&lp->d_partitions[RAW_PART])); |