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It is possible that number of sectors specified in the BPB

Browse Source 
will exceed FAT capacity. This will lead to kernel panic while other
systems just limit number of clusters.

PR:		4381, 15136
Reviewed by:	phk
This commit is contained in:
Boris Popov 1999-12-28 15:27:39 +00:00
parent b7e246cf9e
commit 499d3ffa94
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=55188
4 changed files with 28 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
sys/fs/msdosfs/msdosfs_vfsops.c
View File

@ -364,6 +364,7 @@ mountmsdosfs(devvp, mp, p, argp)
struct byte_bpb50 *b50;
struct byte_bpb710 *b710;
u_int8_t SecPerClust;
u_long clusters;
int ronly, error;
/*
@ -595,14 +596,13 @@ mountmsdosfs(devvp, mp, p, argp)
pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
}
pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
SecPerClust;
pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
SecPerClust + 1;
pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
#ifndef __FreeBSD__
if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
if ((pmp->pm_nmbrofclusters <= (0xff0 - 2))
if ((pmp->pm_maxcluster <= (0xff0 - 2))
&& ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
&& ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
) {
@ -633,6 +633,15 @@ mountmsdosfs(devvp, mp, p, argp)
pmp->pm_fatdiv = 1;
}
}
clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
if (pmp->pm_maxcluster >= clusters) {
printf("Warning: number of clusters (%ld) exceeds FAT "
"capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
pmp->pm_maxcluster = clusters - 1;
}
if (FAT12(pmp))
pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
else
@ -829,7 +838,7 @@ msdosfs_statfs(mp, sbp, p)
pmp = VFSTOMSDOSFS(mp);
sbp->f_bsize = pmp->pm_bpcluster;
sbp->f_iosize = pmp->pm_bpcluster;
sbp->f_blocks = pmp->pm_nmbrofclusters;
sbp->f_blocks = pmp->pm_maxcluster + 1;
sbp->f_bfree = pmp->pm_freeclustercount;
sbp->f_bavail = pmp->pm_freeclustercount;
sbp->f_files = pmp->pm_RootDirEnts; /* XXX */

1
sys/fs/msdosfs/msdosfsmount.h
View File

@ -73,7 +73,6 @@ struct msdosfsmount {
u_long pm_rootdirblk; /* block # (cluster # for FAT32) of root directory number */
u_long pm_rootdirsize; /* size in blocks (not clusters) */
u_long pm_firstcluster; /* block number of first cluster */
u_long pm_nmbrofclusters; /* # of clusters in filesystem */
u_long pm_maxcluster; /* maximum cluster number */
u_long pm_freeclustercount; /* number of free clusters */
u_long pm_cnshift; /* shift file offset right this amount to get a cluster number */

19
sys/msdosfs/msdosfs_vfsops.c
View File

@ -364,6 +364,7 @@ mountmsdosfs(devvp, mp, p, argp)
struct byte_bpb50 *b50;
struct byte_bpb710 *b710;
u_int8_t SecPerClust;
u_long clusters;
int ronly, error;
/*
@ -595,14 +596,13 @@ mountmsdosfs(devvp, mp, p, argp)
pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
}
pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
SecPerClust;
pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
SecPerClust + 1;
pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
#ifndef __FreeBSD__
if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
if ((pmp->pm_nmbrofclusters <= (0xff0 - 2))
if ((pmp->pm_maxcluster <= (0xff0 - 2))
&& ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
&& ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
) {
@ -633,6 +633,15 @@ mountmsdosfs(devvp, mp, p, argp)
pmp->pm_fatdiv = 1;
}
}
clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
if (pmp->pm_maxcluster >= clusters) {
printf("Warning: number of clusters (%ld) exceeds FAT "
"capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
pmp->pm_maxcluster = clusters - 1;
}
if (FAT12(pmp))
pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
else
@ -829,7 +838,7 @@ msdosfs_statfs(mp, sbp, p)
pmp = VFSTOMSDOSFS(mp);
sbp->f_bsize = pmp->pm_bpcluster;
sbp->f_iosize = pmp->pm_bpcluster;
sbp->f_blocks = pmp->pm_nmbrofclusters;
sbp->f_blocks = pmp->pm_maxcluster + 1;
sbp->f_bfree = pmp->pm_freeclustercount;
sbp->f_bavail = pmp->pm_freeclustercount;
sbp->f_files = pmp->pm_RootDirEnts; /* XXX */

1
sys/msdosfs/msdosfsmount.h
View File

@ -73,7 +73,6 @@ struct msdosfsmount {
u_long pm_rootdirblk; /* block # (cluster # for FAT32) of root directory number */
u_long pm_rootdirsize; /* size in blocks (not clusters) */
u_long pm_firstcluster; /* block number of first cluster */
u_long pm_nmbrofclusters; /* # of clusters in filesystem */
u_long pm_maxcluster; /* maximum cluster number */
u_long pm_freeclustercount; /* number of free clusters */
u_long pm_cnshift; /* shift file offset right this amount to get a cluster number */