diff options
| author | Kenneth R Westerback <krw@cvs.openbsd.org> | 2008-01-24 12:23:36 +0000 |
|---|---|---|
| committer | Kenneth R Westerback <krw@cvs.openbsd.org> | 2008-01-24 12:23:36 +0000 |
| commit | 2bf42661c229ba8669629455704cf2dfa25f312d (patch) | |
| tree | 22546e814255124568c3d8c6d2579312bf9aa37d /sbin/disklabel | |
| parent | 573412fd7b9a8fe8e8a528839f7c9f91d9ca8f59 (diff) | |
"read(..., ..., sizeof Y) < sizeof Y" is a dangerous idiom because it
does an unsigned comparison and read() can return -1. Use '!=' instead
of '<' since read() can't return more than 'sizeof Y'. Not perfect
(that would require a separate test for -1) but a very common usage.
Do the same for a write(), and a couple of read() calls which are
probably ok but why be inconsistant?
This, as the last couple of commits, found by ian@ as a result of
poking around in fsck_msdos() when his new iPod had problems vs
OpenBSD.
Concept reviewed by miod@, beck@, otto@ and ian@.
Diffstat (limited to 'sbin/disklabel')
| -rw-r--r-- | sbin/disklabel/disklabel.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/sbin/disklabel/disklabel.c b/sbin/disklabel/disklabel.c index e25aad48ae1..5e074770b01 100644 --- a/sbin/disklabel/disklabel.c +++ b/sbin/disklabel/disklabel.c @@ -1,4 +1,4 @@ -/* $OpenBSD: disklabel.c,v 1.121 2008/01/21 20:07:11 sobrado Exp $ */ +/* $OpenBSD: disklabel.c,v 1.122 2008/01/24 12:23:35 krw Exp $ */ /* * Copyright (c) 1987, 1993 @@ -39,7 +39,7 @@ static const char copyright[] = #endif /* not lint */ #ifndef lint -static const char rcsid[] = "$OpenBSD: disklabel.c,v 1.121 2008/01/21 20:07:11 sobrado Exp $"; +static const char rcsid[] = "$OpenBSD: disklabel.c,v 1.122 2008/01/24 12:23:35 krw Exp $"; #endif /* not lint */ #include <sys/param.h> @@ -572,7 +572,7 @@ writelabel(int f, char *boot, struct disklabel *lp) for (i = 1; i < 11 && i < lp->d_nsectors; i += 2) { (void)lseek(f, (alt + i) * lp->d_secsize, SEEK_SET); if (!donothing) - if (write(f, boot, lp->d_secsize) < lp->d_secsize) + if (write(f, boot, lp->d_secsize) != lp->d_secsize) warn("alternate label %d write", i/2); } } @@ -624,7 +624,7 @@ readmbr(int f) */ dp = (struct dos_partition *)mbr; if (lseek(f, (off_t)DOSBBSECTOR * DEV_BSIZE, SEEK_SET) < 0 || - read(f, mbr, sizeof(mbr)) < sizeof(mbr)) + read(f, mbr, sizeof(mbr)) != sizeof(mbr)) return (NULL); signature = *((u_char *)mbr + DOSMBR_SIGNATURE_OFF) | (*((u_char *)mbr + DOSMBR_SIGNATURE_OFF + 1) << 8); @@ -694,7 +694,7 @@ readlabel(int f) sectoffset/DEV_BSIZE + (LABELSECTOR * DEV_BSIZE) + LABELOFFSET); if (lseek(f, sectoffset, SEEK_SET) < 0 || - read(f, bootarea, BBSIZE) < BBSIZE) + read(f, bootarea, BBSIZE) != BBSIZE) err(4, "%s", specname); lp = (struct disklabel *)(bootarea + @@ -782,7 +782,7 @@ makebootarea(char *boot, struct disklabel *dp, int f) if (!installboot) { #ifndef __i386__ if (rflag) { - if (read(f, boot, BBSIZE) < BBSIZE) + if (read(f, boot, BBSIZE) != BBSIZE) err(4, "%s", specname); memset(lp, 0, sizeof *lp); } |