The branch main has been updated by mckusick:
URL:
https://cgit.FreeBSD.org/src/commit/?id=f3f5368dfbef4514686ba2d67f01f314b275227e
commit f3f5368dfbef4514686ba2d67f01f314b275227e
Author: Kirk McKusick <mckus...@freebsd.org>
AuthorDate: 2022-07-06 20:28:07 +0000
Commit: Kirk McKusick <mckus...@freebsd.org>
CommitDate: 2022-07-06 21:45:29 +0000
Bug fix to UFS/FFS superblock integrity checks when reading a superblock.
The tests for number of cylinder groups (fs_ncg), inodes per cylinder
group (fs_ipg), and the size and layout of the cylinder group summary
information (fs_csaddr and fs_cssize) were overly restrictive and
would exclude some valid filesystems. These updates avoid precluding
valid fiesystems while still detecting rogue values that can crash or
hang the kernel.
Reported by: Chuck Silvers
Tested by: Peter Holm
MFC after: 1 month (with 076002f24d35)
Differential Revision: https://reviews.freebsd.org/D35219
---
sys/ufs/ffs/ffs_subr.c | 34 ++++++++++++++++------------------
1 file changed, 16 insertions(+), 18 deletions(-)
diff --git a/sys/ufs/ffs/ffs_subr.c b/sys/ufs/ffs/ffs_subr.c
index f4c854172fb3..438745f8eb49 100644
--- a/sys/ufs/ffs/ffs_subr.c
+++ b/sys/ufs/ffs/ffs_subr.c
@@ -330,8 +330,8 @@ readsuper(void *devfd, struct fs **fsp, off_t sblockloc,
int isaltsblk,
static int
validate_sblock(struct fs *fs, int isaltsblk)
{
- int i, sectorsize;
- u_int64_t maxfilesize, minfpg, sizepb;
+ u_long i, sectorsize, cgnum;
+ u_int64_t maxfilesize, sizepb;
sectorsize = dbtob(1);
if (fs->fs_magic == FS_UFS2_MAGIC) {
@@ -409,7 +409,6 @@ validate_sblock(struct fs *fs, int isaltsblk)
CHK(fs->fs_iblkno, !=, fs->fs_cblkno + fs->fs_frag, %jd);
CHK(fs->fs_dblkno, !=, fs->fs_iblkno + fs->fs_ipg / INOPF(fs), %jd);
CHK(fs->fs_cgsize, >, fs->fs_bsize, %jd);
- CHK(fs->fs_csaddr, !=, cgdmin(fs, 0), %jd);
CHK(fs->fs_cssize, !=,
fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
CHK(fs->fs_dsize, !=, fs->fs_size - fs->fs_sblkno -
@@ -429,24 +428,24 @@ validate_sblock(struct fs *fs, int isaltsblk)
* makes it hard to tightly bound them. So we can only check
* that they are within a broader possible range.
*
- * Calculate minfpg, the minimum number of fragments that can be
- * in a cylinder group. The value 12289 is calculated in newfs(8)
- * when creating the smallest block size UFS version 1 filesystem
- * (4096 block size) with no fragments (4096 fragment size). That
- * number may be depressed even further for very small filesystems
- * since newfs(8) strives to have at least four cylinder groups.
+ * The size cannot always be accurately determined, but ensure
+ * that it is consistent with the number of cylinder groups (fs_ncg)
+ * and the number of fragments per cylinder group (fs_fpg). Ensure
+ * that the summary information size is correct and that it starts
+ * and ends in the data area of the same cylinder group.
*/
- minfpg = MIN(12289, fs->fs_size / 4);
CHK(fs->fs_ncg, <, 1, %jd);
- CHK(fs->fs_ncg, >, (fs->fs_size / minfpg) + 1, %jd);
- CHK(fs->fs_fpg, <, minfpg, %jd);
- CHK(fs->fs_fpg, >, fs->fs_size, %jd);
- CHK(fs->fs_ipg * fs->fs_ncg, >, (((int64_t)(1)) << 32) - INOPB(fs),
- %jd);
- CHK(fs->fs_ipg, >, fs->fs_fpg, %jd);
CHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
CHK(fs->fs_size, <=, (fs->fs_ncg - 1) * fs->fs_fpg, %jd);
CHK(fs->fs_size, >, fs->fs_ncg * fs->fs_fpg, %jd);
+ CHK(fs->fs_cssize, !=,
+ fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
+ cgnum = dtog(fs, fs->fs_csaddr);
+ CHK(fs->fs_csaddr, <, cgdmin(fs, cgnum), %jd);
+ CHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize)), >,
+ cgnum, %jd);
+ CHK(fs->fs_ipg * fs->fs_ncg, >, (((int64_t)(1)) << 32) - INOPB(fs),
+ %jd);
/*
* With file system clustering it is possible to allocate
* many contiguous blocks. The kernel variable maxphys defines
@@ -466,9 +465,8 @@ validate_sblock(struct fs *fs, int isaltsblk)
* those (mostly 32-bit machines) can (very slowly) handle I/O
* requests that exceed maxphys.
*/
- CHK(fs->fs_maxcontig, <, 1, %jd);
- CHK(fs->fs_maxcontig, >, MAX(256, maxphys / fs->fs_bsize), %jd);
CHK(fs->fs_maxcontig, <, 0, %jd);
+ CHK(fs->fs_maxcontig, >, MAX(256, maxphys / fs->fs_bsize), %jd);
CHK2(fs->fs_maxcontig, ==, 0, fs->fs_contigsumsize, !=, 0, %jd);
CHK2(fs->fs_maxcontig, >, 1, fs->fs_contigsumsize, !=,
MIN(fs->fs_maxcontig, FS_MAXCONTIG), %jd);
